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Emscripten: An LLVM-to-WebAssembly Compiler
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memory alignment issue that only occurs with specific buffer sizes (image dimensions) and results in leaks #14459

Open CetinSert opened 3 years ago

CetinSert commented 3 years ago

In a project compiled with emscripten (em++) to WASM, calls to a function with some image dimensions keep triggering

  memalign memset free
  memalign memset free
  memalign memset

repeatedly on every function call. When the function eventually returns a memory reference, this works as expected when probed with image-related functions for height, width, etc. BUT it cannot be deallocated and leak completely.

Other image dimensions both work and deallocate just fine; calling the function with such good dimensions do NOT keep triggering the above memalign โ‹ฏ repeatedly.

The behavior persists across

Please

Investigation Details ๐Ÿ•ต๐Ÿปโ€โ™‚๏ธ

https://github.com/paulo-coutinho/pdfium-lib/issues/33#issuecomment-861669272 paulo-coutinho/pdfium-lib/blob/master/modules/wasm.py (how the project uses emscripten)

Single-line Reproduction ๐Ÿ”ฌ

  1. Go to https://pdfviewer.github.io/
  2. Open developer console F12
  3. Evaluate the following in the console:
_PDFium_Init();
  1. Evaluate the following line several times and watch the memory grow:
var w = 496, h = 496; for (let i = 0; i < 5; i++) _FPDFBitmap_Destroy(FPDF.Bitmap_CreateEx(w, h, 4)); [ wasmMemory, wasmMemory.buffer.byteLength ] // โŒ
๐Ÿ‘‰๐Ÿป 496 ร— 496 ร— 4 โŒ memalign โ‹ฏ trigger on each iteration ๐Ÿ‘ˆ๐Ÿป (CLICK/TAP HERE TO REVIEW EXECUTION) ``` CreateEx memalign memset free memalign memset free memalign memset Destroy CreateEx memalign memset free memalign memset free memalign memset Destroy CreateEx memalign memset free memalign memset free memalign memset Destroy CreateEx memalign memset free memalign memset free memalign memset Destroy CreateEx memalign memset free memalign memset free memalign memset Destroy ```

image

  1. Note that this one is totally fine and does not leak:
var w = 495, h = 495; for (let i = 0; i < 5; i++) _FPDFBitmap_Destroy(FPDF.Bitmap_CreateEx(w, h, 4)); [ wasmMemory, wasmMemory.buffer.byteLength ] // โœ”๏ธ
๐Ÿ‘‰๐Ÿป 496 ร— 496 ร— 4 โœ”๏ธ memalign โ‹ฏ trigger only once ๐Ÿ‘ˆ๐Ÿป (CLICK/TAP HERE TO REVIEW EXECUTION) ``` CreateEx memalign memset free memalign memset free memalign memset Destroy CreateEx Destroy CreateEx Destroy CreateEx Destroy CreateEx Destroy ```

I kindly ask emscripten experts for their help in finding how to compile the said project in a way that resolves this issue.

Investigation Details ๐Ÿ•ต๐Ÿปโ€โ™‚๏ธ

https://github.com/paulo-coutinho/pdfium-lib/issues/33#issuecomment-861669272 paulo-coutinho/pdfium-lib/blob/master/modules/wasm.py (how the project uses emscripten)

FPDFBitmap_CreateEx call tree

kripken commented 3 years ago

To investigate this, the first thing I'd do is find out if this is fragmentation or leaking. Fragmentation may be caused when doing many allocations and frees, after which it cannot find contiguous chunks and so ends up growing the total size of memory. dlmalloc mentions that aligned memory may be more vulnerable to that,

https://github.com/emscripten-core/emscripten/blob/320532825edd967d2811b74b5c96779cab48cb28/system/lib/dlmalloc.c#L971

To verify that, I'd instrument malloc, memalign, and free (and also realloc etc. if used). Just counting the bytes allocated and freed. One way to instrument it is to compile with WASM=0 and add some code in JS. Or, use mallinfo(), see https://emscripten.org/docs/porting/Debugging.html#memory (the memory profiler mentioned there can also help).

If you find that the codebase you are compiling allocates more than it frees, then it would be a leak in the code. If instead it frees everything it allocates, then I'd guess the problem is fragmentation.

If it is fragmentation in fact, then the codebase might benefit from reusing buffers, using an arena, etc.

CetinSert commented 3 years ago

@kripken โ€“ can increasing the wasmMemory page size from 64KB to something higher also help with fragmentation?

I will answer myself: this is not even possible as 64KB is a constant โ€“ https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/Memory/Memory#parameters.

CetinSert commented 3 years ago

To verify that, I'd instrument malloc, memalign, and free (and also realloc etc. if used). Just counting the bytes allocated and freed. One way to instrument it is to compile with WASM=0 ...

Instrumentation seemed easy even without WASM=0.

(() => {
  const ins = (f, n) => (...a) => { const v = f(...a); console.warn(n, f, v, '<-', a); return v; };
  const { malloc, memalign, memset, free, realloc } = Module.asm;
  Module.asm = { ...Module.asm,
    malloc:   ins(malloc,   'malloc  '),
    memalign: ins(memalign, 'memalign'),
    memset:   ins(memset,   'memset  '),
    free:     ins(free,     'free    '),
    realloc:  ins(realloc,  'realloc ')
  };
})();

image

but the instrumented functions only get called when the now infamous memalign โ‹ฏ trio triggers. So we get limited improved vision.

CetinSert commented 3 years ago

@kripken โ€“ updated the original issue with more data from the instrumentation (which does trigger repeatedly on every time as it is a new known bad case and bad cases trigger the memalign โ‹ฏ pattern in a way (at a layer) that also triggers the instrumentation), please take a look at the new comment linked below to see if it reminds you of any pattern you or other developers of emscripten recognize.

https://github.com/paulo-coutinho/pdfium-lib/issues/33#issuecomment-863587472

kripken commented 3 years ago

Instrumenting Module.asm like that will just affect calls that go through JS. Direct calls inside the wasm would not be noticed.

If that is not a problem, then the logging does show a leak in the codebase, as there is no free for the third memalign. To investigate that you could get a stack trace for that allocation, then try to figure out where the free should be, etc.

CetinSert commented 3 years ago

If it is fragmentation in fact, then the codebase might benefit from reusing buffers, using an arena, etc.

I assume there is no way to compact / vacuum the memory.

To investigate that you could get a stack trace for that allocation, then try to figure out where the free should be, etc.

  1. Is there a compile/run-time option to reduce/eliminate these memalign โ‹ฏ calls to test if codebase still works?
  2. What would do a memalign(65535, โ‹ฏ)? Should 65535 not be a small number that is more like 4 because WASM is 32-bit?
  3. Get a stack trace in JS or C++ or via an emscripten compilation option?
    (I have not compiled this module myself, have been treating it as a blackbox so far.)
CetinSert commented 3 years ago

If that is not a problem, then the logging does show a leak in the codebase, as there is no free for the third memalign. To investigate that you could get a stack trace for that allocation, then try to figure out where the free should be, etc.

The original C++ codebase was checked and found to not suffer from memory leaks:

Here is how em++ is being called: https://github.com/paulo-coutinho/pdfium-lib/blob/c95bc4a72502251bd3ee770d57907812945c6a2d/modules/wasm.py#L674.

Here is how the WASM builds are being made by the repository owner.

PDFium build steps ๐Ÿ‘ˆ๐Ÿป (dockerized short version)

Docker

You can use docker to build and test on local machine before deploy.

Build the image with command:

docker build -t pdfium-wasm -f docker/wasm/Dockerfile docker/wasm

Test with command:

docker run -v ${PWD}:/app -it pdfium-wasm echo "test"

Now you can execute any command with pattern:

docker run -v ${PWD}:/app -it pdfium-wasm [COMMAND]

Obs: This is the recommended way to build and is used on CD server.

Run on browser

You can test the sample using commands:

โ‹ฎ

docker run -v ${PWD}:/app -it pdfium-wasm python3 make.py run test-wasm
python3 -m http.server --directory sample-wasm/build

Run on terminal

You can test the sample using commands:

โ‹ฎ

docker run -v ${PWD}:/app -it pdfium-wasm python3 make.py run test-wasm
docker run -v ${PWD}:/app -it pdfium-wasm node sample-wasm/build/index.js

Web demo

You can test pdfium on web browser here:

https://pdfviewer.github.io/

References Quoted

  1. https://github.com/paulo-coutinho/pdfium-lib/blob/master/README.md
  2. https://github.com/paulo-coutinho/pdfium-lib/blob/master/docs/BUILD_WASM.md

CetinSert commented 3 years ago

Further improved the instrumentation in https://github.com/paulo-coutinho/pdfium-lib/issues/33#issuecomment-863707842 to keep counts and added screenshots.

(() => {

  M = new Map();
  M.sum = () => [...M.values()].reduce((a, c) => a + c, 0);
  M.cnt = { malloc: 0, free: 0, sum: 0 };
  M.fn  = { malloc: 0, memalign: 1 };
  M.add = (n, a) => { M.   set(a, n); M.cnt.malloc++; M.cnt.sum += n; };
  M.sub =     a  => { M.delete(a   ); M.cnt.free++;                   };

  const ins = (f, n) => (...a) => {
    const v =  f(...a), d = a[M.fn[n]] ?? 0;
    if (d   >      0) M.add(d, v);
    if (n === 'free') M.sub(a[0]);
    console.warn(n.padEnd(8), f, `${v}`.padStart(20), '<-', (a.length == 1 ? [...a, '-'] : a).map(a => `${a}`.padStart(20)).join(' '), '|', `${wasmMemory.buffer.byteLength}`.padStart(20), '|', `${M.sum()}`.padStart(20), 'M', M.size); return v;
  };

  const { malloc, memalign, memset, free, realloc } = Module.asm;
  Module.asm = { ...Module.asm,
    malloc:   ins(malloc,   'malloc'),
    memalign: ins(memalign, 'memalign'/*.length == 8*/),
  //memset:   ins(memset,   'memset'),
    free:     ins(free,     'free'),
    realloc:  ins(realloc,  'realloc')
  };

})();

image

  1. Why would/might only some arguments to Bitmap_CreateEx cause repeated memalign โ‹ฏ calls?
    After testing again, it does indeed seem that going beyond 495 ร— 495 ร— 4 triggers memalign โ‹ฏ reliably.
    So, size seems to play a role here but why?
  2. The Bitmap_Destroy(Bitmap_CreateEx(โ‹ฏ)) calls were tested in C++ by me and Google as linked above and were found to not leak in that environment at any size. (see https://github.com/emscripten-core/emscripten/issues/14459#issuecomment-863656321)
  3. Is em++ generating/placing the memalign โ‹ฏ calls into the compiled WASM binary?
  4. How can we avoid these? Can we re-compile in a different way, with a different configuration / flags to avoid them?
    I have noticed we are building with -O3 on which the manual page of em++ reads
       -O3    As -O2, plus dangerous optimizations that may break the generated
              code! This adds

              -s FORCE_ALIGNED_MEMORY=1 -s DOUBLE_MODE=0 -s PRECISE_I64_MATH=0
              --closure 1 --llvm-lto 1

              This is not recommended at all. A better idea is to try each of
              these separately on top of -O2 to see what works. See the wiki and
              src/settings.js (for the -s options) for more information.

Testing with -O2 seems to not help. Re-confirming with an independent build soon ...

kripken commented 3 years ago

I assume there is no way to compact / vacuum the memory.

Correct. That is a general issue with languages using linear memory. On native platforms this is also a problem, mostly on 32-bit (as on 64-bit virtual memory can be used to work around it).

You can get a stack trace programmatically by console.log(new Error().stack) for example. Or you can get a trace running in the debugger.

em++ may call memalign in some cases for internal reasons (like if you call mmap). The stack trace should help figure that out.

CetinSert commented 3 years ago

You can get a stack trace programmatically by console.log(new Error().stack) for example. Or you can get a trace running in the debugger.

image

Here is the stack trace.

kripken commented 3 years ago

Thanks, ok, then the allocation happens here in mmap:

https://github.com/emscripten-core/emscripten/blob/7192647ca6d3add7291338b735a166fd3409edca/src/library_syscall.js#L248

and the free should happen here in munmap:

https://github.com/emscripten-core/emscripten/blob/7192647ca6d3add7291338b735a166fd3409edca/src/library_syscall.js#L302

I don't see anything obviously wrong there, and in our test suite the tests pass (and I verified we check that free is called on the right pointer).

Is it possible the codebase you are compiling does not call munmap on what it mmaps?

CetinSert commented 3 years ago

Is it possible the codebase you are compiling does not call munmap on what it mmaps?

checking now ... (as a note, other target / compiler pairs have no such issues as tested twice here: https://github.com/emscripten-core/emscripten/issues/14459#issuecomment-863656321)

I have also tried other mallocs emscripten ships with ... nothing helped there either. (TODO: add data)

Also tried all sanitizer, debug options and the only leaks that get detected is when we run out of 2GB WASM memory a mere 48 bytes (TODO: add data).

CetinSert commented 3 years ago

Is it possible the codebase you are compiling does not call munmap on what it mmaps?

Found the culprit I believe:

  1. No, the codebase clearly calls munmap on what it mmaps โœ”๏ธ (see below)
  2. munmap sometimes (with a regular pattern) fails to call free โŒ (see below)
    ๐Ÿ’ก
    This turned out to be because munmap is getting called with a shorter length than how much was mmaped to that address.
    This was discovered further below in this separate comment: https://github.com/emscripten-core/emscripten/issues/14459#issuecomment-864400904 .

Immediate Reproduction Link

Please review this link where I have done a lot to get as much ready-to-see info out as possible!

https://pdf.ist/em/14459/ (ready to produce the below screenshot)

  1. navigate to https://pdf.ist/em/14459/
  2. open the developer console (F12)
  3. evaluate the following one line at a time in the developer console

    (This will reproduce the exact Screenshot of the Issue below,
    which I have also annotated here with โœ”๏ธ โŒ marks for your convenience.)

1 time

_PDFium_Init(); clear();

3 times

_PDFium_Init(); var w = 496, h = 496; for (let i = 0; i < 1; i++) _FPDFBitmap_Destroy(_FPDFBitmap_CreateEx(w, h, 4)); [ wasmMemory, wasmMemory.buffer.byteLength ] // โŒ

Screenshot of the Issue

โœ”๏ธ munmap calls free โœ”๏ธ munmap calls free โŒ munmap does not call free

Is it possible the codebase you are compiling does not call munmap on what it mmaps?

No, at all 3 times, munmap is called with the output from mmap (visible in the screenshot).

image

๐Ÿ‘‰๐Ÿป instrumentation code ๐Ÿ‘ˆ๐Ÿป ```js (() => { M = new Map(); M.sum = () => [...M.values()].reduce((a, c) => a + c, 0); M.cnt = { malloc: 0, free: 0, sum: 0 }; M.fn = { malloc: 0, memalign: 1 }; M.add = (n, a) => { M. set(a, n); M.cnt.malloc++; M.cnt.sum += n; }; M.sub = a => { M.delete(a ); M.cnt.free++; }; const ins = (f, n) => (...a) => { const v = f(...a), d = a[M.fn[n]] ?? 0; if (d > 0) M.add(d, v); if (n === 'free') M.sub(a[0]); console.warn(n.padEnd(8), f, `${v}`.padStart(20), '<-', (a.length == 1 ? [...a, '-'] : a).map(a => `${a}`.padStart(20)).join(' '), '|', `${wasmMemory.buffer.byteLength}`.padStart(20), '|', `${M.sum()}`.padStart(20), 'M', M.size); return v; }; const { malloc, memalign, memset, free, realloc } = Module.asm; Module.asm = { ...Module.asm, malloc: ins(malloc, 'malloc'), memalign: ins(memalign, 'memalign'/*.length == 8*/), //memset: ins(memset, 'memset'), free: ins(free, 'free'), realloc: ins(realloc, 'realloc') }; })(); ```
๐Ÿ‘‰๐Ÿป instrumentation output legend ๐Ÿ‘ˆ๐Ÿป ``` function โ‹ฏ return arguments wasmMemory tracked memory L =============== โ‹ฏ ========= ========================================= =============== ==================== = malloc ฦ’ 4497 โ‹ฏ 16584728 <- 16 - | 44040192 | 16 M 1 free ฦ’ 4498 โ‹ฏ undefined <- 16584728 - | 44040192 | 0 M 0 ```
๐Ÿ‘‰๐Ÿป console output copy / paste ๐Ÿ‘ˆ๐Ÿป ``` pdfium.js?v=4543:4924 syscall! __sys_mmap2: [0,1007616,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.729 VM1972:14 memalign ฦ’ 8416() { [native code] } 339804160 <- 65536 1007616 | 1073741824 | 1007616 M 1 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.729 pdfium.js?v=4543:4939 syscall return: 339804160 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.729 pdfium.js?v=4543:4979 syscall! __sys_munmap: [339804160,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.730 VM1972:14 free ฦ’ 8409() { [native code] } undefined <- 339804160 - | 1073741824 | 0 M 0 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMunmap @ pdfium.js?v=4543:4972 (anonymous) @ pdfium.js?v=4543:4983 ___sys_munmap @ pdfium.js?v=4543:4990 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.730 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.730 pdfium.js?v=4543:4924 syscall! __sys_mmap2: [341835776,1007616,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.731 VM1972:14 memalign ฦ’ 8416() { [native code] } 341114880 <- 65536 1007616 | 1073741824 | 1007616 M 1 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.731 pdfium.js?v=4543:4939 syscall return: 341114880 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.731 pdfium.js?v=4543:4979 syscall! __sys_munmap: [341114880,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.731 VM1972:14 free ฦ’ 8409() { [native code] } undefined <- 341114880 - | 1073741824 | 0 M 0 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMunmap @ pdfium.js?v=4543:4972 (anonymous) @ pdfium.js?v=4543:4983 ___sys_munmap @ pdfium.js?v=4543:4990 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.731 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.731 pdfium.js?v=4543:4924 syscall! __sys_mmap2: [0,3100672,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.733 VM1972:14 memalign ฦ’ 8416() { [native code] } 342425600 <- 65536 3100672 | 1073741824 | 3100672 M 1 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.733 pdfium.js?v=4543:4939 syscall return: 342425600 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.733 pdfium.js?v=4543:4979 syscall! __sys_munmap: [342425600,1507328] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.733 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.733 pdfium.js?v=4543:4979 syscall! __sys_munmap: [344940544,585728] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.733 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.734 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [343932928,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.734 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.734 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [343932928,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.734 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.734 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [344915968,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.734 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.734 pdfium.js?v=4543:4979 syscall! __sys_munmap: [343932928,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::FreePages(void*, unsigned long) @ sstream:887 pdfium::base::internal::DeferredUnmap::Unmap() @ sstream:887 FX_Free(void*) @ custom.cpp:27 CFX_DIBitmap::~CFX_DIBitmap().1 @ locale:1425 FPDFBitmap_Destroy @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.734 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::FreePages(void*, unsigned long) @ sstream:887 pdfium::base::internal::DeferredUnmap::Unmap() @ sstream:887 FX_Free(void*) @ custom.cpp:27 CFX_DIBitmap::~CFX_DIBitmap().1 @ locale:1425 FPDFBitmap_Destroy @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1980:1 17:06:00.738 (2)ย [Memory(16384), 1073741824] 17:06:03.370 _PDFium_Init(); var w = 496, h = 496; for (let i = 0; i < 1; i++) _FPDFBitmap_Destroy(_FPDFBitmap_CreateEx(w, h, 4)); [ wasmMemory, wasmMemory.buffer.byteLength ] // โŒ 17:06:03.370 pdfium.js?v=4543:4924 syscall! __sys_mmap2: [0,1007616,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.371 VM1972:14 memalign ฦ’ 8416() { [native code] } 345833472 <- 65536 1007616 | 1073741824 | 4108288 M 2 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.371 pdfium.js?v=4543:4939 syscall return: 345833472 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.371 pdfium.js?v=4543:4979 syscall! __sys_munmap: [345833472,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.372 VM1972:14 free ฦ’ 8409() { [native code] } undefined <- 345833472 - | 1073741824 | 3100672 M 1 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMunmap @ pdfium.js?v=4543:4972 (anonymous) @ pdfium.js?v=4543:4983 ___sys_munmap @ pdfium.js?v=4543:4990 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.372 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.372 pdfium.js?v=4543:4924 syscall! __sys_mmap2: [346030080,1007616,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.373 VM1972:14 memalign ฦ’ 8416() { [native code] } 347144192 <- 65536 1007616 | 1073741824 | 4108288 M 2 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.373 pdfium.js?v=4543:4939 syscall return: 347144192 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.373 pdfium.js?v=4543:4979 syscall! __sys_munmap: [347144192,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.373 VM1972:14 free ฦ’ 8409() { [native code] } undefined <- 347144192 - | 1073741824 | 3100672 M 1 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMunmap @ pdfium.js?v=4543:4972 (anonymous) @ pdfium.js?v=4543:4983 ___sys_munmap @ pdfium.js?v=4543:4990 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.373 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.373 pdfium.js?v=4543:4924 syscall! __sys_mmap2: [4096,3100672,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 VM1972:14 memalign ฦ’ 8416() { [native code] } 348454912 <- 65536 3100672 | 1073741824 | 6201344 M 2 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4939 syscall return: 348454912 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4979 syscall! __sys_munmap: [348454912,1769472] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4979 syscall! __sys_munmap: [351232000,323584] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [350224384,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [350224384,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.375 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [351207424,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.376 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.376 pdfium.js?v=4543:4979 syscall! __sys_munmap: [350224384,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::FreePages(void*, unsigned long) @ sstream:887 pdfium::base::internal::DeferredUnmap::Unmap() @ sstream:887 FX_Free(void*) @ custom.cpp:27 CFX_DIBitmap::~CFX_DIBitmap().1 @ locale:1425 FPDFBitmap_Destroy @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.376 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::FreePages(void*, unsigned long) @ sstream:887 pdfium::base::internal::DeferredUnmap::Unmap() @ sstream:887 FX_Free(void*) @ custom.cpp:27 CFX_DIBitmap::~CFX_DIBitmap().1 @ locale:1425 FPDFBitmap_Destroy @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1985:1 17:06:03.391 (2)ย [Memory(16384), 1073741824] 17:06:05.043 _PDFium_Init(); var w = 496, h = 496; for (let i = 0; i < 1; i++) _FPDFBitmap_Destroy(_FPDFBitmap_CreateEx(w, h, 4)); [ wasmMemory, wasmMemory.buffer.byteLength ] // โŒ 17:06:05.043 pdfium.js?v=4543:4924 syscall! __sys_mmap2: [0,1007616,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.044 VM1972:14 memalign ฦ’ 8416() { [native code] } 351862784 <- 65536 1007616 | 1073741824 | 7208960 M 3 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.044 pdfium.js?v=4543:4939 syscall return: 351862784 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.044 pdfium.js?v=4543:4979 syscall! __sys_munmap: [351862784,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.044 VM1972:14 free ฦ’ 8409() { [native code] } undefined <- 351862784 - | 1073741824 | 6201344 M 2 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMunmap @ pdfium.js?v=4543:4972 (anonymous) @ pdfium.js?v=4543:4983 ___sys_munmap @ pdfium.js?v=4543:4990 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.044 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.044 pdfium.js?v=4543:4924 syscall! __sys_mmap2: [352321536,1007616,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.046 VM1972:14 memalign ฦ’ 8416() { [native code] } 353173504 <- 65536 1007616 | 1073741824 | 7208960 M 3 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.046 pdfium.js?v=4543:4939 syscall return: 353173504 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.046 pdfium.js?v=4543:4979 syscall! __sys_munmap: [353173504,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.046 VM1972:14 free ฦ’ 8409() { [native code] } undefined <- 353173504 - | 1073741824 | 6201344 M 2 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMunmap @ pdfium.js?v=4543:4972 (anonymous) @ pdfium.js?v=4543:4983 ___sys_munmap @ pdfium.js?v=4543:4990 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.046 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.046 pdfium.js?v=4543:4924 syscall! __sys_mmap2: [4096,3100672,3,34,-1,0] ___sys_mmap2 @ pdfium.js?v=4543:4924 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.048 VM1972:14 memalign ฦ’ 8416() { [native code] } 354484224 <- 65536 3100672 | 1073741824 | 9302016 M 3 (anonymous) @ VM1972:14 (anonymous) @ pdfium.js?v=4543:1222 syscallMmap2 @ pdfium.js?v=4543:4900 (anonymous) @ pdfium.js?v=4543:4928 ___sys_mmap2 @ pdfium.js?v=4543:4935 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4939 syscall return: 354484224 ___sys_mmap2 @ pdfium.js?v=4543:4939 __mmap @ mmap.c:29 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4979 syscall! __sys_munmap: [354484224,2031616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4979 syscall! __sys_munmap: [357523456,61440] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4994 syscall return: 0 ___sys_munmap @ pdfium.js?v=4543:4994 __munmap @ munmap.c:11 pdfium::base::AllocPages(void*, unsigned long, unsigned long, pdfium::base::PageAccessibilityConfiguration, pdfium::base::PageTag, bool) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [356515840,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [356515840,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4944 syscall! __sys_mprotect: [357498880,65536,0] ___sys_mprotect @ pdfium.js?v=4543:4944 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4952 syscall return: 0 ___sys_mprotect @ pdfium.js?v=4543:4952 __mprotect @ mprotect.c:10 pdfium::base::SetSystemPagesAccess(void*, unsigned long, pdfium::base::PageAccessibilityConfiguration) @ sstream:887 pdfium::base::internal::PartitionBucket::SlowPathAlloc(pdfium::base::internal::PartitionRootBase*, int, unsigned long, bool*) @ sstream:887 pdfium::internal::Calloc(unsigned long, unsigned long) @ custom.cpp:27 CFX_DIBitmap::Create(int, int, FXDIB_Format, unsigned char*, unsigned int) @ locale:1425 FPDFBitmap_CreateEx @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4979 syscall! __sys_munmap: [356515840,1007616] ___sys_munmap @ pdfium.js?v=4543:4979 __munmap @ munmap.c:11 pdfium::base::FreePages(void*, unsigned long) @ sstream:887 pdfium::base::internal::DeferredUnmap::Unmap() @ sstream:887 FX_Free(void*) @ custom.cpp:27 CFX_DIBitmap::~CFX_DIBitmap().1 @ locale:1425 FPDFBitmap_Destroy @ sstream:887 (anonymous) @ pdfium.js?v=4543:1222 (anonymous) @ VM1990:1 17:06:05.049 pdfium.js?v=4543:4994 syscall return: 0 ``` 
โ‹ฎ
  if (len === info.len) { // โŒ this check fails on the 3rd call
โ‹ฎ

image

https://pdf.ist/em/14459/ โ€“ further instrumented for your convenience.

function syscallMmap2(addr, len, prot, flags, fd, off) {
 โ‹ฎ
 console.warn('๐Ÿ•ต๐Ÿปโ€โ™‚๏ธ๐Ÿ“–', 'mmap2 ', { addr, len, prot, fd, off }, "โ†’", ptr, "โ†’", SYSCALLS.mappings[ptr]);
 return ptr;
}
function syscallMunmap(addr, len) {
 if ((addr | 0) === -1 || len === 0) {
  return -28;
 }
 var info = SYSCALLS.mappings[addr];
 console.warn('๐Ÿ•ต๐Ÿปโ€โ™‚๏ธ๐Ÿ“˜', 'munmap', { addr, len }, "โ†’", { ...info }, { 'len ===': len === info?.len ? 'โœ”๏ธ' : 'โŒ' });
 โ‹ฎ
}

image

CetinSert commented 3 years ago

image Is it not safe to change this

if (len === info.len)

to this

if (len <=  info.len)

assuming emscripten bookkeeps the memory block from info.malloc to info.malloc + info.len as reserved anyway?

References

https://pubs.opengroup.org/onlinepubs/9699919799/ (๐Ÿ” munmap, mmap) https://pubs.opengroup.org/onlinepubs/9699919799/functions/munmap.html

sbc100 commented 3 years ago

Is the code in question trying to partial unmapping of anonymous regions?

We don't support that, and I don't think there is any easy way to fake it. We should really be asserting in that case. We also don't support mprotect at all. We should assert there too.

Is the code in question doing anonymous mapping or file-backed mappings?

If its just anonymous mappings then I best thing to do is to find a way to tell the upstream code the we don't really support mmap at all. Is there perhaps a HAS_MMAP macro that you can turn off?

CetinSert commented 3 years ago

@sbc100 โ€“ thank you for the prompt response. I am only blackbox probing the codebase for a personal project.

@paulo-coutinho โ€“ can you please review these issues and discuss them with the PDFium group like you have done in the past here, https://github.com/paulo-coutinho/pdfium-lib/issues/22 for a way out?

@paulo-coutinho โ€“ https://groups.google.com/g/pdfium/c/cDkppTy9mEc (posted here with references to related issues)

paulocoutinhox commented 3 years ago

Ok, i will check it.

CetinSert commented 3 years ago

@kripken does that mean the latest PDFium can no longer be compiled with em++ without source code modifications?

It does seem like you were involved with a commercial project compiling PDFium with emscripten (https://pspdfkit.com/blog/2019/webassembly-emscripten-chat-alon-zakai/). Would you mind sharing with the open source community here what you already know or could learn from that company by asking them so that their limited commercial interests are not the only thing that benefits from the combined power of PDFium and emscripten?

(Whether PDFium actually does partial munmap when built with other compilers for other targets is not yet confirmed. I have asked one of their developers if they could answer that question for us. Should that not result in a clear answer, I will try instrumenting the C++ codebase by whatever means necessary to get the answer. (Not sure of LD_LIBRARY_PATH will be of value for munmap, although I have already used it to replace malloc, free in a Linux system successfully.)

CetinSert commented 3 years ago

Please note: https://github.com/emscripten-core/emscripten/pull/14504#issuecomment-865648164

CetinSert commented 3 years ago

For reference, per https://groups.google.com/g/pdfium/c/cDkppTy9mEc/m/2_4sjSdqAwAJ, PDFium calls both munmap and mmap only in 1 file (re-confirmed with source code search tools).

The corresponding Windows implementation in โ‹ฏ_win.h

  1. suggests that the โ‹ฏ_posix.h implementation does actually perform partial munmaps
  2. demonstrates a potential solution for a short patch for targeting WASM with emscripten

https://pdfium.googlesource.com/pdfium.git/+/refs/heads/chromium/4543/third_party/base/allocator/partition_allocator/page_allocator_internals_win.h#52

void* TrimMappingInternal(โ‹ฏ
โ‹ฎ
    // We cannot resize the allocation run. Free it and retry at the aligned
    // address within the freed range.
โ‹ฎ
}

@kripken โ€“ do you see anything else in https://pdfium.googlesource.com/pdfium.git/+/refs/heads/chromium/4543/third_party/base/allocator/partition_allocator/page_allocator_internals_posix.h that emscripten/em++ does not implement that we should be aware of?

(It is the only file with posix in the name in PDFium code base (except for 2 other files related to file access which do not apply in WASM builds).)

sbc100 commented 3 years ago

Reading to code briefly it seems like the current codebase has has issues under emscirpten both before and after #14459. Please tell my if my understanding not correct here: PDFium is always trying to allocate memory with 2Mb alignment (kSuperPageSize). To do this it is calling mmap with a suggested address (arg0 which is the hint) which it aligns to 2Mb. This hint is completely ignored by emscripten so the result will pretty much always fail to be 2Mb aligned. When the result is not 2Mb aligned PDFium will then over-allocates by 2Mb and then try to trim the result by munmaping the regions at the start and the end. This munmap'ing will silently fail on emscripten prior to #14459 and abort after #14459.

However, one key observation is that when the munmap would previously silently fail pdfium can then never free the aligned result. See TrimMappingInternal:

  if (pre_slack) {                                                               
    int res = munmap(base, pre_slack);                                           
    CHECK(!res);                                                                                                               
    ret = reinterpret_cast<char*>(base) + pre_slack;                                
  }

When mmunamp silently fails here PDFium adjusts the resulting pointer to form a new pointer that is now un-freeable. This is no longer a pointer that can be passed to munmap in the future since the underlying malloc implementation is not tracking it.

I think the ultimate solution here is to patch PDFium such that under emscripten is simply calls posix_memalign(kSuperPageSize, ...); to get it aligned memory.

CetinSert commented 3 years ago

I think the ultimate solution here is to patch PDFium such that under emscripten is simply calls posix_memalign(kSuperPageSize, ...); to get it aligned memory.

@sbc100 โ€“ umm, where in which file?

References

kSuperPageSize โ€“ https://pdfium.googlesource.com/pdfium.git/+/refs/heads/chromium/4543/third_party/base/allocator/partition_allocator/partition_alloc_constants.h

CetinSert commented 3 years ago

I am trying replacing

https://pdfium.googlesource.com/pdfium.git/+/refs/heads/chromium/4543/third_party/base/allocator/partition_allocator/page_allocator_internals_posix.h#129

void* TrimMappingInternal(void* base,
                          size_t base_length,
                          size_t trim_length,
                          PageAccessibilityConfiguration accessibility,
                          bool commit,
                          size_t pre_slack,
                          size_t post_slack) {
  void* ret = base;
  // We can resize the allocation run. Release unneeded memory before and after
  // the aligned range.
  if (pre_slack) {
    int res = munmap(base, pre_slack);
    CHECK(!res);
    ret = reinterpret_cast<char*>(base) + pre_slack;
  }
  if (post_slack) {
    int res = munmap(reinterpret_cast<char*>(ret) + trim_length, post_slack);
    CHECK(!res);
  }
  return ret;
}

with

https://pdfium.googlesource.com/pdfium.git/+/refs/heads/chromium/4543/third_party/base/allocator/partition_allocator/page_allocator_internals_win.h#52

void* TrimMappingInternal(void* base,
                          size_t base_length,
                          size_t trim_length,
                          PageAccessibilityConfiguration accessibility,
                          bool commit,
                          size_t pre_slack,
                          size_t post_slack) {
  void* ret = base;
  if (pre_slack || post_slack) {
    // We cannot resize the allocation run. Free it and retry at the aligned
    // address within the freed range.
    ret = reinterpret_cast<char*>(base) + pre_slack;
    FreePages(base, base_length);
    ret = SystemAllocPages(ret, trim_length, accessibility, PageTag::kChromium,
                           commit);
  }
  return ret;
}

as we speak.

Seems to help in the most basic cases such as;

_PDFium_Init(); var s = 496; for (let i = 0; i < 1; i++) FPDF.Bitmap_Destroy(FPDF.Bitmap_CreateEx(s, s, 4)); [ wasmMemory.buffer.byteLength ]

but fails when more stuff is happening such as when actually rendering pages:

image

it tends to hang when attempting a new render after the above error.

sbc100 commented 3 years ago

I think that the entire TrimMappingInternal and TrimMapping should not be included in the emscripten build. Trimming an existing mapping is not really possible with a malloc-backed mmap. I think we should instead just use posix_memalign to get an allocation that is already aligned (as opposed to using the hint parameter to mmap which seems like strictly less precise way to express the intent to the underlying allocator).

In other words, on systems which don't have real mmap support lets avoid mmap completely.

CetinSert commented 3 years ago

@sbc100 โ€“ That would suggest we would need a new file like page_allocator_internals_em.h. As my C experience is not up to speed to create one, can you or anyone else come up with the necessary changes / a complete example? If you want compensation because this is beyond the scope of emscripten, please write to me at work@pdf.ist and we can discuss the conditions. (The resulting work can from my point of view be licensed as BSD3 (the same license the rest of PDFium uses).)

sbc100 commented 3 years ago

I don't think I will have the time to add this myself, but I suggest we/you reach out to folks who work on PDFium and see if we can persuade them to add (or at least accept) a no-mmap version of that codepath.

kripken commented 3 years ago

@cetinsert

Thanks for the feedback on that PR. Let's iterate there to find the right solution.

It does seem like you were involved with a commercial project compiling PDFium with emscripten

I think that was just a friendly chat about wasm that I did on their blog. I don't know anything about their codebase.

CetinSert commented 3 years ago

@kripken โ€“ thank you for the friendly response! I have just learned how to compile the WASM builds without missing a step re-using a stale file and am now testing the โ‹ฏ_win.h approach described here https://github.com/emscripten-core/emscripten/issues/14459#issuecomment-866066268 which was considered worth a try by someone from Google too (https://groups.google.com/g/pdfium/c/cDkppTy9mEc/m/EIK5_FGIAwAJ).

CetinSert commented 3 years ago

@sbc100 โ€“ trying โ‹ฏ_win.h approach as described here https://github.com/emscripten-core/emscripten/issues/14459#issuecomment-866066268

seems to help in the most basic cases such as;

_PDFium_Init(); var s = 496; for (let i = 0; i < 1; i++) FPDF.Bitmap_Destroy(FPDF.Bitmap_CreateEx(s, s, 4)); [ wasmMemory.buffer.byteLength ]

but fails when more stuff is happening such as when actually rendering pages:

image

it tends to hang when attempting a new render after the above error.

sbc100 commented 3 years ago

I don't think that will work. The main reason is that the hint argument which is the first argument to SystemAllocPages is ignored under emscripten. As I said, I think you are going to want a more specific, higher level, solution that avoids SystemAllocPages completely and uses something like posix_memalign instead. Hopefully this can be done upstream: https://groups.google.com/g/pdfium/c/cDkppTy9mEc.

CetinSert commented 3 years ago

Any chance of this https://github.com/emscripten-core/emscripten/blob/7192647ca6d3add7291338b735a166fd3409edca/src/library_syscall.js#L282

getting done in emscripten?

sbc100 commented 3 years ago

Any chance of this

https://github.com/emscripten-core/emscripten/blob/7192647ca6d3add7291338b735a166fd3409edca/src/library_syscall.js#L282

getting done in emscripten?

Since WebAssembly doesn't have access the virtual memory subsystem its hard to see a useful/sensible way to implement this. I suppose these is the possibility of writing a separate page allocator that operates on a different chunk of memory to the malloc heap? But we have no plans to do that. Its also something that could just as well be implemented in user space. i.e. we don't any system primitives that make sense here.

CetinSert commented 3 years ago

Lei Zhang from PDFium has signaled willingness in accepting a WASM-only memory management patch upstream: https://groups.google.com/g/pdfium/c/cDkppTy9mEc/m/k976It-QAwAJ

@sbc100 @kripken โ€“ the best I can do (with my active knowledge of C/C++) is extend this approach https://github.com/emscripten-core/emscripten/issues/14459#issuecomment-866066268 by doing a full translation of โ‹ฏ_win.h and use that for WASM. If you look at the โ‹ฏwin.h linked in that comment, do you still see problems remaining because of hint or is Windows behaving like WASM in SystemAllocPages too? Should a different approach be needed altogether, how/where can we find a developer willing to deliver a solution here?

sbc100 commented 3 years ago

I'm talking to some folks who work on PDFium about getting a upstream patch.

CetinSert commented 3 years ago

@sbc100 โ€“ hello!

Is anyone making any progress on this? Can you provide us (@paulo-coutinho, @cetinsert) links and contacts where / with whom we can follow up?

sbc100 commented 3 years ago

Sorry I haven't had any time to look into it. We have approval to make an emscripten-specific version of the page allocator in PDFium but I don't think I will have time to do it myself.

paulocoutinhox commented 3 years ago

@cetinsert

Do you have knowledge to do it?

CetinSert commented 3 years ago

@paulo-coutinho โ€“ I have limited experience with memory allocators. The fanciest thing I have ever done is LD_LIBRARY_PATH= a different malloc library to replace the glibc one which had been the cause of incessant segfaults in a Linux installation that was half-apt upgraded; no changes in legacy code, fix working like a charm: no segfaults ever happening again, no memory corruption either.

It would speed things up if we connect with the right people as any output from me will likely take weeks at best. Perhaps @sbc100 or @kripken could briefly sketch out in pseudo-code or plaintext what needs to be replaced and how so we can give it a try!

CetinSert commented 3 years ago

@paulo-coutinho โ€“ ffmpeg was recently ported to WebAssembly (a few months ago); perhaps their community might have had to deal with / get past similar issues.

paulocoutinhox commented 3 years ago

Hi,

Any solution for this?

Thanks.

stale[bot] commented 2 years ago

This issue has been automatically marked as stale because there has been no activity in the past year. It will be closed automatically if no further activity occurs in the next 30 days. Feel free to re-open at any time if this issue is still relevant.

paulocoutinhox commented 2 years ago

Any news on this?