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`%ecx' not allowed with `orb' #961

Closed nickdesaulniers closed 4 years ago

nickdesaulniers commented 4 years ago

x86_64 defconfig linux-next

    /tmp/cpudeadline-106401.s:76: Error: `%ecx' not allowed with `orb'
ihalip commented 4 years ago

No error with clang 10+, only clang-9 seems to have this issue. I'm guessing it's a clang bug which was exposed by commit 1651e700664b.

https://godbolt.org/z/LKtvej

nathanchance commented 4 years ago

Can confirm (Letterkenny anyone?):

$ ./build-llvm.py --build-stage1-only --branch llvmorg-9.0.1 --install-stage1-only --install-folder ${PWD}/llvm-9.0.1
...

$ ./build-llvm.py --build-stage1-only --branch llvmorg-10.0.0 --install-stage1-only --install-folder ${PWD}/llvm-10.0.0
...

$ PATH=${PWD}/llvm-9.0.1/bin:${PATH} make -C "${SRC_FOLDER}"/linux-next -j$(nproc) -s CC=clang HOSTCC=clang O=out/x86_64 distclean defconfig all
/tmp/cpudeadline-0b2789.s: Assembler messages:
/tmp/cpudeadline-0b2789.s:76: Error: `%ecx' not allowed with `orb'
clang-9: error: assembler command failed with exit code 1 (use -v to see invocation)
...

$ PATH=${PWD}/llvm-10.0.0/bin:${PATH} make -C "${SRC_FOLDER}"/linux-next -j$(nproc) -s CC=clang HOSTCC=clang O=out/x86_64 distclean defconfig all
...

$ echo ${?}
0

I'll see if I can do a reverse bisect to figure out what commit fixed this, just to make sure it was an intentional fix rather than some sort of subtle change in behavior.

nathanchance commented 4 years ago 
$ git bisect log
git bisect start '--term-old' 'broken' '--term-new' 'fixed'
# broken: [c89a3d78f43d81b9cff7b9248772ddf14d21b749] [lldb][NFC] Format 'type' commands in Options.td
git bisect broken c89a3d78f43d81b9cff7b9248772ddf14d21b749
# fixed: [5852475e2c049ce29dcb1f0da3ac33035f8c9156] Bump the trunk major version to 11
git bisect fixed 5852475e2c049ce29dcb1f0da3ac33035f8c9156
# fixed: [7e1a3076419d4d453d71143a1e81409ea1db177c] [LLDB] [PECOFF] Don't crash in ReadImageDataByRVA for addresses out of range
git bisect fixed 7e1a3076419d4d453d71143a1e81409ea1db177c
# broken: [4e76f880723a4a1a25a94f556aea72f63da8f17a] [SimplifyCFG][NFC] Autogenerate PhiEliminate3.ll
git bisect broken 4e76f880723a4a1a25a94f556aea72f63da8f17a
# broken: [e0a398bf3195746d026d06721a5521d21cc23f3e] [process list] make the TRIPLE column wider
git bisect broken e0a398bf3195746d026d06721a5521d21cc23f3e
# fixed: [b65fa483058f1b4049c7201525779b4f49cceb80] [Alignment] Migrate Attribute::getWith(Stack)Alignment
git bisect fixed b65fa483058f1b4049c7201525779b4f49cceb80
# broken: [adc5043fa2749d2a38139e6429837651d4936569] TestIndirectSymbols: Modernize the Makefile
git bisect broken adc5043fa2749d2a38139e6429837651d4936569
# broken: [b3faa01ff9625cc00d98d5fffd597c64d494c349] IOHandler: fall back on File::Read if a FILE* isn't available.
git bisect broken b3faa01ff9625cc00d98d5fffd597c64d494c349
# broken: [b32e4664a7156830aa6a5c97d9074269574b1f98] [ConstantFold] fix inconsistent handling of extractelement with undef index (PR42689)
git bisect broken b32e4664a7156830aa6a5c97d9074269574b1f98
# fixed: [d5768e3d0e887ba75222c6ceda9c6fa2c93e00c1] Fix test breakage caused by r374424
git bisect fixed d5768e3d0e887ba75222c6ceda9c6fa2c93e00c1
# broken: [5a8db8496440b9d6ced91bd24f4b6b463acc7d55] DWARFExpression: Fix/add support for (v4) debug_loc base address selection entries
git bisect broken 5a8db8496440b9d6ced91bd24f4b6b463acc7d55
# fixed: [1385b27e92d906dbce9dd10431c8c210d1f7ef45] [CostModel][X86] Add CTLZ scalar costs
git bisect fixed 1385b27e92d906dbce9dd10431c8c210d1f7ef45
# broken: [a5ef3daf1d776384eff624725dfc1738e02ad018] [ARM] Add some VMOVN tests. NFC
git bisect broken a5ef3daf1d776384eff624725dfc1738e02ad018
# broken: [543236232c79221c4da261246e49888844697539] [ARM] Selection for MVE VMOVN
git bisect broken 543236232c79221c4da261246e49888844697539
# broken: [ee86804cf1bc7f9d9935261231b95e8f30dd7c03] [x86] adjust select to sra tests; NFC
git bisect broken ee86804cf1bc7f9d9935261231b95e8f30dd7c03
# fixed: [2cb43b45713daca087449e6f1b1aced95b895435] [ARM] Preserve fpu behaviour for '-crypto'
git bisect fixed 2cb43b45713daca087449e6f1b1aced95b895435
# fixed: [9681ea9560a00038a29ed368dfa32104b0597b26] Reapply r374743 with a fix for the ocaml binding
git bisect fixed 9681ea9560a00038a29ed368dfa32104b0597b26
# first fixed commit: [9681ea9560a00038a29ed368dfa32104b0597b26] Reapply r374743 with a fix for the ocaml binding

llvm/llvm-project@9681ea9560a00038a29ed368dfa32104b0597b26

nickdesaulniers commented 4 years ago

I guess that means clang-9 is going to stop working?

nathanchance commented 4 years ago

Unless we can convince them to fix that problem in another way (if that is indeed the commit that causes this error), it seems like it :/

nickdesaulniers commented 4 years ago

Maybe we can work around it in the kernel. We could see what registers GCC or a working clang choose, and use those in the input constraints, maybe, with a preprocessor check on the clang version.

Definitely calls into question #941 and what we want our support model to be.

nathanchance commented 4 years ago

Maybe we can work around it in the kernel. We could see what registers GCC or a working clang choose, and use those in the input constraints, maybe, with a preprocessor check on the clang version.

Depends on if upstream is going to be okay with working around a compiler bug. I wish LLVM had longer support periods like GCC but I guess that wouldn't really matter in this instance since the patch that fixes it is probably on the larger side for a stable release.

Definitely calls into question #941 and what we want our support model to be.

Yeah I agree... Maybe that conversation needs to be had sooner rather than later. This is part of the reason that I want to step up testing of stable LLVM releases.

ihalip commented 4 years ago

These come from https://github.com/ClangBuiltLinux/linux/blob/919dce24701f7b34681a6a1d3ef95c9f6c4fb1cc/arch/x86/include/asm/bitops.h#L52.

clang 10 & 11, and all versions of GCC I've tested on godbolt.org seem to always use the bts branch (when __builtin_constant_p(nr) != true). clang-9 on the other hand uses the orb branch in one case (in cpumask_set_cpu() to be more precise, but that's not really important):

$ grep orb kernel/sched/cpudeadline.s
    lock; orb %ecx,(%rdx,%r8)

So I tried to force both clang and GCC to use orb, by deleting some code in arch_set_bit():

static __always_inline void
arch_set_bit(long nr, volatile unsigned long *addr)
{
       asm volatile(LOCK_PREFIX "orb %1,%0"
               : CONST_MASK_ADDR(nr, addr)
               : "iq" (CONST_MASK(nr) & 0xff)
               : "memory");
}

There are similar errors (Error: %e[abcd]x' not allowed withorb') with both compilers.

nickdesaulniers commented 4 years ago

all versions of GCC I've tested on godbolt.org seem to always use the bts branch (when __builtin_constant_p(nr) != true)

So it sounds like Clang is more aggressive with the compile time constant here, but...

There are similar errors (Error: %e[abcd]x' not allowed with orb') with both compilers.

...the compile time constant branch is broken for both compilers?

Maybe it should be removed then, or the constraints fixed, or a different instruction used? Why doesn't orb allow GPRs? Does it require a memory operand? Or a literal value?

Actually, something seems funny. I know that "i" constraint means integer literal, so it doesn't make sense that operand %1 ends up as a register. I don't know what "q" is off the top of my head, but I wonder if that is problematic, and should be removed?

Or maybe we need to use a print modifier, orb %c1,%0 to force it to be a literal?

nathanchance commented 4 years ago

FYI, this will now affect mainline: f14a9532ee30c68a56ff502c382860f674cc180c

ihalip commented 4 years ago

...the compile time constant branch is broken for both compilers?

Yes.

Maybe it should be removed then, or the constraints fixed, or a different instruction used? Why doesn't orb allow GPRs? Does it require a memory operand? Or a literal value?

orb is or over byte, it accepts immediates, general registers, memory... but the input should be 1 byte long. If I re-add the cast to u8, like so:

diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 53f246e9df5a..213809fc8720 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -54,7 +54,7 @@ arch_set_bit(long nr, volatile unsigned long *addr)
        if (__builtin_constant_p(nr)) {
                asm volatile(LOCK_PREFIX "orb %1,%0"
                        : CONST_MASK_ADDR(nr, addr)
-                       : "iq" (CONST_MASK(nr) & 0xff)
+                       : "iq" ((u8)(CONST_MASK(nr) & 0xff))
                        : "memory");
        } else {
                asm volatile(LOCK_PREFIX __ASM_SIZE(bts) " %1,%0"
@@ -74,7 +74,7 @@ arch_clear_bit(long nr, volatile unsigned long *addr)
        if (__builtin_constant_p(nr)) {
                asm volatile(LOCK_PREFIX "andb %1,%0"
                        : CONST_MASK_ADDR(nr, addr)
-                       : "iq" (CONST_MASK(nr) ^ 0xff));
+                       : "iq" ((u8)(CONST_MASK(nr) ^ 0xff)));
        } else {
                asm volatile(LOCK_PREFIX __ASM_SIZE(btr) " %1,%0"
                        : : RLONG_ADDR(addr), "Ir" (nr) : "memory");

, this compiles nicely with both compilers. Inputs are now 8-bit registers:

$ grep "lock; orb" kernel/sched/cpudeadline.s # GCC
    lock; orb %al,(%rdx)    # tmp127, *_63
    lock; orb %al,0(%rbp)   # tmp142, *_63
    lock; orb %dl,(%rax)    # tmp101, *_10
$ grep "lock; orb" kernel/sched/cpudeadline.s # clang-11
    lock; orb %dil,(%rdx,%rsi)
    lock; orb %al,8(%rbx,%r15)
    lock; orb %dl,8(%rdi,%rax)

So we either this cast needs to be re-added, or change the inline assembly from orb to the more general or. Jesse, who originally submitted the patch, also added a test module for the change. Let me check if I can change that module to better expose this issue with GCC.

nathanchance commented 4 years ago

This actually appears to also be an issue with LLVM 11 with Linux at bef7b2a7be28... I can reproduce it with Arch Linux's config.

$ curl -LSso .config 'https://git.archlinux.org/svntogit/packages.git/plain/trunk/config?h=packages/linux'

$ make -j$(nproc) -s CC=clang LD=ld.lld olddefconfig drivers/staging/vt6656/key.o
/tmp/key-254602.s: Assembler messages:
/tmp/key-254602.s:380: Error: `%ebp' not allowed with `orb'
...

The casting patch works for this as well it seems like.

nathanchance commented 4 years ago 

$ cat key.i
void a() {
  long b;
  asm("orb %1,%0" : "+miq"(b));
}

$ gcc -O2 -c -o /dev/null key.i

$ clang -O2 -no-integrated-as -c -o /dev/null key.i
/tmp/key-f2d048.s: Assembler messages:
/tmp/key-f2d048.s:11: Error: `%rax' not allowed with `orb'
clang-11: error: assembler command failed with exit code 1 (use -v to see invocation)

$ clang -O2 -c -o /dev/null key.i
key.i:3:7: error: invalid operand for instruction
  asm("orb %1,%0" : "+miq"(b));
      ^
<inline asm>:1:6: note: instantiated into assembly here
        orb %rax,%rax
            ^~~~~
1 error generated.
dileks commented 4 years ago

Confirmed: I see this when compiling Linux v5.7-rc1 with clang-10 from llvm-toolchain-buster-10.

Any progress on this? Is there an official fix for Linux-kernel or LLVM/Clang?

Error lines from my build-log:

mycompiler -Wp,-MD,drivers/staging/vt6656/.key.o.d  -nostdinc -isystem /usr/lib/llvm-10/lib/clang/10.0.0/include -I./arch/x86/include -I./arch/x86/include/generated  -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -Qunused-arguments -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE -Werror=implicit-function-declaration -Werror=implicit-int -Wno-format-security -std=gnu89 -no-integrated-as -Werror=unknown-warning-option -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -m64 -mno-80387 -mstack-alignment=8 -mtune=generic -mno-red-zone -mcmodel=kernel -Wno-sign-compare -fno-asynchronous-unwind-tables -mretpoline-external-thunk -fno-delete-null-pointer-checks -Wno-address-of-packed-member -O2 -Wframe-larger-than=2048 -fstack-protector-strong -Wno-format-invalid-specifier -Wno-gnu -mno-global-merge -Wno-unused-const-variable -g -pg -mfentry -DCC_USING_FENTRY -Wdeclaration-after-statement -Wvla -Wno-pointer-sign -fno-strict-overflow -fno-merge-all-constants -fno-stack-check -Werror=date-time -Werror=incompatible-pointer-types -fmacro-prefix-map=./= -fcf-protection=none -Wno-initializer-overrides -Wno-format -Wno-sign-compare -Wno-format-zero-length -Wno-tautological-constant-out-of-range-compare -DLINUX -D__KERNEL__ -DEXPORT_SYMTAB -D__NO_VERSION__ -DHOSTAP  -DMODULE  -DKBUILD_BASENAME='"key"' -DKBUILD_MODNAME='"vt6656_stage"' -c -o drivers/staging/vt6656/key.o drivers/staging/vt6656/key.c
...
/tmp/key-5194ed.s: Assembler messages:
/tmp/key-5194ed.s:1574: Error: `%ebx' not allowed with `orb'
clang: error: assembler command failed with exit code 1 (use -v to see invocation)
make[6]: *** [scripts/Makefile.build:266: drivers/staging/vt6656/key.o] Error 1
make[5]: *** [scripts/Makefile.build:488: drivers/staging/vt6656] Error 2
make[4]: *** [scripts/Makefile.build:488: drivers/staging] Error 2

Patch from @ihalip seems to work, Thanks.

$ make CC=clang-10 drivers/staging/vt6656/key.o
...
CC [M]  drivers/staging/vt6656/key.o

UPDATE: Add Error lines from my build-log UPDATE-2: Feedback on patch from @ihalip

dileks commented 4 years ago

I am building with @ihalip patch and an adapted version of "[v6,2/2] lib: make a test module with set/clear bit ".

[1] has instructions on how to test with CONFIG_TEST_BITOPS=m.

I will report later.

[1] https://lore.kernel.org/patchwork/patch/1208077/

ihalip commented 4 years ago

For key.c in particular, clang unrolls the loop at line 54, so set_bit is called with known values for i, which is why the orb branch is selected.

I'm pretty sure the (u8) cast should be re-added, I just need to build a strong enough case to put in the commit message.

nickdesaulniers commented 4 years ago

I think the cast and the mask should be fine. (Mask then cast, to satisfy sparse warning and compiler codegen)

dileks commented 4 years ago

BTW, we have also u8 cast in arch_change_bit():

arch/x86/include/asm/bitops.h-static __always_inline void
arch/x86/include/asm/bitops.h-arch_change_bit(long nr, volatile unsigned long *addr)
arch/x86/include/asm/bitops.h-{
arch/x86/include/asm/bitops.h-  if (__builtin_constant_p(nr)) {
arch/x86/include/asm/bitops.h-          asm volatile(LOCK_PREFIX "xorb %1,%0"
arch/x86/include/asm/bitops.h:                  : CONST_MASK_ADDR(nr, addr)
arch/x86/include/asm/bitops.h:                  : "iq" ((u8)CONST_MASK(nr)));
arch/x86/include/asm/bitops.h-  } else {
arch/x86/include/asm/bitops.h-          asm volatile(LOCK_PREFIX __ASM_SIZE(btc) " %1,%0"
arch/x86/include/asm/bitops.h-                  : : RLONG_ADDR(addr), "Ir" (nr) : "memory");
arch/x86/include/asm/bitops.h-  }
arch/x86/include/asm/bitops.h-}
dileks commented 4 years ago

Updated my local llvm-toolchain from release/10.x Git branch with tc-build.

Still building with attached two patches.

x86-bitops-clang-Fix-CBL-issue-961_patch.txt lib-make-a-test-module-with-set-clear-bit_patch.txt

ihalip commented 4 years ago

The generated assembly for key.c where this error happens looks like this:

1.  movl    %esi, %ecx  // nr
2.  andb    $7, %cl
3.  movl    $1, %ebx
4.  shll    %cl, %ebx   // (1 << ((nr) & 7))
5.  movzbl  %bl, %ecx
6.  lock; orb %ecx,2792(%rdi,%r14)

So this does seem like a combination of 1) clang using a GPR for nr (a consequence of loop unrolling?) 2) integer promotion at line 5

@dileks may I add your Tested-by in a patch?

dileks commented 4 years ago

@ihalip Yes for the patch.

I was able to build successfully and boot on bare metal with above 2 patches.

$ cat /proc/version 
Linux version 5.7.0-rc1-4-amd64-clang (sedat.dilek@gmail.com@iniza) (ClangBuiltLinux clang version 10.0.1 (https://github.com/ClangBuiltLinux/tc-build.git 61b6007157600d8080b87361397bb61ffbcfb196), LLD 10.0.1 (https://github.com/ClangBuiltLinux/tc-build.git 61b6007157600d8080b87361397bb61ffbcfb196)) #4~bullseye+dileks1 SMP 2020-04-14

No warnings on load/unload of test_bitops module:

$ dmesg | tail

[  853.830098] test_bitops: Loaded test module
[  945.504070] test_bitops: Unloaded test module

Objdump attached:

$ objdump -S -d lib/test_bitops.ko

lib/test_bitops.ko:     file format elf64-x86-64

Disassembly of section .init.text:

0000000000000000 <init_module>:

static DECLARE_BITMAP(g_bitmap, BITOPS_LENGTH);

static int __init test_bitops_startup(void)
{
        pr_warn("Loaded test module\n");
   0:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
   7:   31 c0                   xor    %eax,%eax
   9:   e8 00 00 00 00          callq  e <init_module+0xe>

static __always_inline void
arch_set_bit(long nr, volatile unsigned long *addr)
{
        if (__builtin_constant_p(nr)) {
                asm volatile(LOCK_PREFIX "orb %1,%0"
   e:   f0 80 0d 00 00 00 00    lock orb $0x10,0x0(%rip)        # 16 <init_module+0x16>
  15:   10 
  16:   f0 80 0d 00 00 00 00    lock orb $0x80,0x0(%rip)        # 1e <init_module+0x1e>
  1d:   80 
  1e:   f0 80 0d 00 00 00 00    lock orb $0x8,0x0(%rip)        # 26 <init_module+0x26>
  25:   08 
  26:   f0 80 0d 00 00 00 00    lock orb $0x80,0x0(%rip)        # 2e <init_module+0x2e>
  2d:   80 
  2e:   f0 80 0d 00 00 00 00    lock orb $0x1,0x0(%rip)        # 36 <init_module+0x36>
  35:   01 
        set_bit(BITOPS_4, g_bitmap);
        set_bit(BITOPS_7, g_bitmap);
        set_bit(BITOPS_11, g_bitmap);
        set_bit(BITOPS_31, g_bitmap);
        set_bit(BITOPS_88, g_bitmap);
        return 0;
  36:   31 c0                   xor    %eax,%eax
  38:   c3                      retq   

Disassembly of section .exit.text:

0000000000000000 <cleanup_module>:

static __always_inline void
arch_clear_bit(long nr, volatile unsigned long *addr)
{
        if (__builtin_constant_p(nr)) {
                asm volatile(LOCK_PREFIX "andb %1,%0"
   0:   f0 80 25 00 00 00 00    lock andb $0xef,0x0(%rip)        # 8 <cleanup_module+0x8>
   7:   ef 
   8:   f0 80 25 00 00 00 00    lock andb $0x7f,0x0(%rip)        # 10 <cleanup_module+0x10>
   f:   7f 
  10:   f0 80 25 00 00 00 00    lock andb $0xf7,0x0(%rip)        # 18 <cleanup_module+0x18>
  17:   f7 
  18:   f0 80 25 00 00 00 00    lock andb $0x7f,0x0(%rip)        # 20 <cleanup_module+0x20>
  1f:   7f 
  20:   f0 80 25 00 00 00 00    lock andb $0xfe,0x0(%rip)        # 28 <cleanup_module+0x28>
  27:   fe 
        clear_bit(BITOPS_7, g_bitmap);
        clear_bit(BITOPS_11, g_bitmap);
        clear_bit(BITOPS_31, g_bitmap);
        clear_bit(BITOPS_88, g_bitmap);

        bit_set = find_first_bit(g_bitmap, BITOPS_LAST);
  28:   be ff 00 00 00          mov    $0xff,%esi
  2d:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  34:   e8 00 00 00 00          callq  39 <cleanup_module+0x39>
        if (bit_set != BITOPS_LAST)
  39:   3d ff 00 00 00          cmp    $0xff,%eax
  3e:   74 10                   je     50 <cleanup_module+0x50>
                pr_err("ERROR: FOUND SET BIT %d\n", bit_set);
  40:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  47:   89 c6                   mov    %eax,%esi
  49:   31 c0                   xor    %eax,%eax
  4b:   e8 00 00 00 00          callq  50 <cleanup_module+0x50>

        pr_warn("Unloaded test module\n");
  50:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  57:   31 c0                   xor    %eax,%eax
  59:   e9 00 00 00 00          jmpq   5e <__UNIQUE_ID_description38+0x1d>

objdump-S-d_test_bitops_ko.txt

dileks commented 4 years ago

Objdump of vt6656_stage.ko attached (fixed version):

$ objdump -S -d drivers/staging/vt6656/vt6656_stage.ko

objdump-S-d_vt6656_stage_ko.txt

dileks commented 4 years ago

Objdump of drivers/staging/vt6656/key.o (fixed version):

MAKE="make V=1"
MAKE_OPTS="CC=mycompiler LD=mylinker HOSTCC=mycompiler HOSTLD=mylinker"

$MAKE $MAKE_OPTS defconfig
scripts/config -m VT6656

$MAKE $MAKE_OPTS drivers/staging/vt6656/key.o

objdump -S -d drivers/staging/vt6656/key.o > /tmp/objdump-S-d_vt6656-key_o.txt

objdump-S-d_vt6656-key_o.txt

dileks commented 4 years ago

@ihalip

Please CC me on any progress: Sedat Dilek sedat.dilek@gmail.com

Thanks.

nickdesaulniers commented 4 years ago

Hi @ihalip , can you please send your patch? KernelCI has been reporting this breakage daily.

dileks commented 4 years ago

Maybe contact the folks from [1] like Jesse Brandeburg?

I have the two patches from [2] in my local Git queue.

As said we have also u8 cast in arch_change_bit() in arch/x86/include/asm/bitops.h, too.

The test_bitops module from Jesse Brandeburg would also be nice to have in the Linux-kernel.

root# modprobe -v test_bitops
insmod /lib/modules/5.7.0-rc3-1-amd64-clang/kernel/lib/test_bitops.ko 
root# modprobe -r -v test_bitops
rmmod test_bitops
root# dmesg | tail
[ 2963.190417] test_bitops: Loaded test module
[ 2968.190282] test_bitops: Unloaded test module

[1] https://git.kernel.org/linus/1651e700664b4597ddf4f8adfe435252a0d11277

[2] https://github.com/ClangBuiltLinux/linux/issues/961#issuecomment-613207374

nickdesaulniers commented 4 years ago

x86_64 defconfig + CONFIG_STAGING=y + CONFIG_VT6656=m. reported upstream: https://lore.kernel.org/lkml/20200504193524.GA221287@google.com/

jbrandeb commented 4 years ago

Thanks guys for this report. That was good investigative work! When you add back the cast I think we're basically going to back to where we started, with the sparse warning, did you check to see if sparse (make C=1) still warns?

nickdesaulniers commented 4 years ago

Probably could have both the mask then cast.

On Mon, May 4, 2020, 3:57 PM Jesse Brandeburg notifications@github.com wrote:

Thanks guys for this report. That was good investigative work! When you add back the cast I think we're basically going to back to where we started, with the sparse warning, did you check to see if sparse (make C=1) still warns?

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/ClangBuiltLinux/linux/issues/961#issuecomment-623750994, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAN5IX24JFQSM5EJD3P5QWTRP5B53ANCNFSM4LXX75TQ .

dileks commented 4 years ago

@nickdesaulniers Thanks for reporting upstream. @jbrandeb Thanks for taking care.

With my two patches from above applied:

$ clang-10 --version 
ClangBuiltLinux clang version 10.0.1 (https://github.com/llvm/llvm-project 92d5c1be9ee93850c0a8903f05f36a23ee835dc2)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/dileks/src/llvm-toolchain/install/bin

$ ld.lld-10 --version
LLD 10.0.1 (https://github.com/llvm/llvm-project 92d5c1be9ee93850c0a8903f05f36a23ee835dc2) (compatible with GNU linkers)

MAKE="make"
MAKE_OPTS="CC=clang-10 LD=ld.lld-10 HOSTCC=clang-10 HOSTLD=ld.lld-10"

$MAKE distclean

$MAKE $MAKE_OPTS defconfig
scripts/config -m TEST_BITOPS

$MAKE $MAKE_OPTS C=1 W=1 lib/test_bitops.ko
scripts/kconfig/conf  --syncconfig Kconfig
  SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
  SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_32.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_64.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_x32.h
  HOSTCC  arch/x86/tools/relocs_32.o
  HOSTCC  arch/x86/tools/relocs_64.o
  HOSTCC  arch/x86/tools/relocs_common.o
  HOSTLD  arch/x86/tools/relocs
  HOSTCC  scripts/selinux/genheaders/genheaders
  HOSTCC  scripts/selinux/mdp/mdp
  HOSTCC  scripts/kallsyms
  HOSTCC  scripts/sorttable
  HOSTCC  scripts/asn1_compiler
  HOSTCC  scripts/extract-cert
  WRAP    arch/x86/include/generated/uapi/asm/bpf_perf_event.h
  WRAP    arch/x86/include/generated/uapi/asm/errno.h
  WRAP    arch/x86/include/generated/uapi/asm/fcntl.h
  WRAP    arch/x86/include/generated/uapi/asm/ioctl.h
  WRAP    arch/x86/include/generated/uapi/asm/ioctls.h
  WRAP    arch/x86/include/generated/uapi/asm/ipcbuf.h
  WRAP    arch/x86/include/generated/uapi/asm/param.h
  WRAP    arch/x86/include/generated/uapi/asm/poll.h
  WRAP    arch/x86/include/generated/uapi/asm/resource.h
  WRAP    arch/x86/include/generated/uapi/asm/socket.h
  WRAP    arch/x86/include/generated/uapi/asm/sockios.h
  WRAP    arch/x86/include/generated/uapi/asm/termbits.h
  WRAP    arch/x86/include/generated/uapi/asm/termios.h
  WRAP    arch/x86/include/generated/uapi/asm/types.h
  WRAP    arch/x86/include/generated/asm/early_ioremap.h
  WRAP    arch/x86/include/generated/asm/export.h
  WRAP    arch/x86/include/generated/asm/mcs_spinlock.h
  WRAP    arch/x86/include/generated/asm/dma-contiguous.h
  WRAP    arch/x86/include/generated/asm/mm-arch-hooks.h
  WRAP    arch/x86/include/generated/asm/mmiowb.h
  UPD     include/config/kernel.release
  UPD     include/generated/uapi/linux/version.h
  UPD     include/generated/utsrelease.h
  CHECK   scripts/mod/empty.c
  CC      scripts/mod/empty.o
  HOSTCC  scripts/mod/mk_elfconfig
  MKELF   scripts/mod/elfconfig.h
  HOSTCC  scripts/mod/modpost.o
  CC      scripts/mod/devicetable-offsets.s
  UPD     scripts/mod/devicetable-offsets.h
  HOSTCC  scripts/mod/file2alias.o
  HOSTCC  scripts/mod/sumversion.o
  HOSTLD  scripts/mod/modpost
  CC      kernel/bounds.s
  UPD     include/generated/bounds.h
  UPD     include/generated/timeconst.h
  CC      arch/x86/kernel/asm-offsets.s
  UPD     include/generated/asm-offsets.h
  CALL    scripts/checksyscalls.sh
  CALL    scripts/atomic/check-atomics.sh
  DESCEND  objtool
  HOSTCC   /home/dileks/src/linux-kernel/linux/tools/objtool/fixdep.o
  HOSTLD   /home/dileks/src/linux-kernel/linux/tools/objtool/fixdep-in.o
  LINK     /home/dileks/src/linux-kernel/linux/tools/objtool/fixdep
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/exec-cmd.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/help.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/pager.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/parse-options.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/run-command.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/sigchain.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/subcmd-config.o
  LD       /home/dileks/src/linux-kernel/linux/tools/objtool/libsubcmd-in.o
  AR       /home/dileks/src/linux-kernel/linux/tools/objtool/libsubcmd.a
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/arch/x86/decode.o
  LD       /home/dileks/src/linux-kernel/linux/tools/objtool/arch/x86/objtool-in.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/builtin-check.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/builtin-orc.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/check.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/orc_gen.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/orc_dump.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/elf.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/special.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/objtool.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/libstring.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/libctype.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/str_error_r.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/librbtree.o
  LD       /home/dileks/src/linux-kernel/linux/tools/objtool/objtool-in.o
  LINK     /home/dileks/src/linux-kernel/linux/tools/objtool/objtool
  CHECK   lib/test_bitops.c
/home/dileks/src/llvm-toolchain/install/lib/clang/10.0.1/include/stdarg.h:26:5: warning: undefined preprocessor identifier '__STDC_VERSION__'
/home/dileks/src/llvm-toolchain/install/lib/clang/10.0.1/include/stdarg.h:26:36: warning: undefined preprocessor identifier '__cplusplus'
  CC [M]  lib/test_bitops.o
  MODPOST 1 modules
  CC [M]  lib/test_bitops.mod.o
  LD [M]  lib/test_bitops.ko
dileks commented 4 years ago

@jbrandeb 

$ objdump -S -d lib/test_bitops.ko  

lib/test_bitops.ko:     file format elf64-x86-64

Disassembly of section .init.text:

0000000000000000 <init_module>:
   0:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
   7:   31 c0                   xor    %eax,%eax
   9:   e8 00 00 00 00          callq  e <init_module+0xe>
   e:   f0 80 0d 00 00 00 00    lock orb $0x10,0x0(%rip)        # 16 <init_module+0x16>
  15:   10 
  16:   f0 80 0d 00 00 00 00    lock orb $0x80,0x0(%rip)        # 1e <init_module+0x1e>
  1d:   80 
  1e:   f0 80 0d 00 00 00 00    lock orb $0x8,0x0(%rip)        # 26 <init_module+0x26>
  25:   08 
  26:   f0 80 0d 00 00 00 00    lock orb $0x80,0x0(%rip)        # 2e <init_module+0x2e>
  2d:   80 
  2e:   f0 80 0d 00 00 00 00    lock orb $0x1,0x0(%rip)        # 36 <init_module+0x36>
  35:   01 
  36:   31 c0                   xor    %eax,%eax
  38:   c3                      retq   

Disassembly of section .exit.text:

0000000000000000 <cleanup_module>:
   0:   f0 80 25 00 00 00 00    lock andb $0xef,0x0(%rip)        # 8 <cleanup_module+0x8>
   7:   ef 
   8:   f0 80 25 00 00 00 00    lock andb $0x7f,0x0(%rip)        # 10 <cleanup_module+0x10>
   f:   7f 
  10:   f0 80 25 00 00 00 00    lock andb $0xf7,0x0(%rip)        # 18 <cleanup_module+0x18>
  17:   f7 
  18:   f0 80 25 00 00 00 00    lock andb $0x7f,0x0(%rip)        # 20 <cleanup_module+0x20>
  1f:   7f 
  20:   f0 80 25 00 00 00 00    lock andb $0xfe,0x0(%rip)        # 28 <cleanup_module+0x28>
  27:   fe 
  28:   be ff 00 00 00          mov    $0xff,%esi
  2d:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  34:   e8 00 00 00 00          callq  39 <cleanup_module+0x39>
  39:   3d ff 00 00 00          cmp    $0xff,%eax
  3e:   74 10                   je     50 <cleanup_module+0x50>
  40:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  47:   89 c6                   mov    %eax,%esi
  49:   31 c0                   xor    %eax,%eax
  4b:   e8 00 00 00 00          callq  50 <cleanup_module+0x50>
  50:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  57:   31 c0                   xor    %eax,%eax
  59:   e9 00 00 00 00          jmpq   5e <__UNIQUE_ID_description39+0x1d>
nickdesaulniers commented 4 years ago

ah, sorry, I missed them @dileks

Can you please send them upstream? I'll test out the first. "x86: bitops: clang: Fix CBL issue #961" Looks like what I had in mind, and I suspect it satisfies both Clang and sparse.

nickdesaulniers commented 4 years ago

Also, for patch 1, you can add:

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>

(I checked with C=1 as well).

Please let me know if you can't send them soon and I'll send your first patch ASAP. I would like to unbreak the x86_64 allyesconfig build ASAP.

dileks commented 4 years ago

@nickdesaulniers

Dear Nick,

I leave it to you - you might have the better wording and explanations as I am not an English native and a real concern/request.

I apologize for being not upstream-friendly the last weeks.

Feel free to add my: Reported-by: Sedat Dilek sedat.dilek@gmail.com Tested-by: Sedat Dilek sedat.dilek@gmail.com Acked-by: Sedat Dilek sedat.dilek@gmail.com (or whatever fits here)

Please give appropriate credits to people involved in this issue like @ihalip etc.

In times of Corona you never know what happens or happened to people and/or their families.

dileks commented 4 years ago

@jbrandeb @nickdesaulniers

I highly appreciate test-cases/test-suites and encourage you to send patch 2/2 (see my polished up version above).

nickdesaulniers commented 4 years ago

@dileks , may I also add your: Signed-off-by: tag?

dileks commented 4 years ago

@nickdesaulniers Yes.

nickdesaulniers commented 4 years ago

submitted: https://lore.kernel.org/lkml/20200505174423.199985-1-ndesaulniers@google.com/T/#u thanks @dileks . Also, you and @jbrandeb should discuss your second patch more.

dileks commented 4 years ago

[v2] x86: bitops: fix build regression

https://lore.kernel.org/patchwork/patch/1237213/

nickdesaulniers commented 4 years ago

v3: https://lore.kernel.org/lkml/20200508180549.212957-1-ndesaulniers@google.com/T/#u

jbrandeb commented 4 years ago

the v5: https://lore.kernel.org/lkml/20200508183230.229464-1-ndesaulniers@google.com/ and I Reviewed-by: on it.

Thanks again!

nickdesaulniers commented 4 years ago

great, thanks for the reviews + testing!

dileks commented 4 years ago

Testing with v5:

dileks@iniza:~/src/linux-kernel/linux$ MAKE="make"
dileks@iniza:~/src/linux-kernel/linux$ MAKE_OPTS="CC=clang-10 LD=ld.lld-10 HOSTCC=clang-10 HOSTLD=ld.lld-10"

dileks@iniza:~/src/linux-kernel/linux$ $MAKE distclean
  CLEAN   arch/x86/entry/vdso
  CLEAN   arch/x86/realmode/rm
  CLEAN   certs
  CLEAN   usr
  CLEAN   arch/x86/tools
  CLEAN   scripts/basic
  CLEAN   scripts/genksyms
  CLEAN   scripts/kconfig
  CLEAN   scripts/mod
  CLEAN   scripts/selinux/genheaders
  CLEAN   scripts/selinux/mdp
  CLEAN   scripts
  CLEAN   include/config include/generated arch/x86/include/generated debian/
  CLEAN   .config

dileks@iniza:~/src/linux-kernel/linux$ $MAKE $MAKE_OPTS defconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  HOSTCC  scripts/kconfig/confdata.o
  HOSTCC  scripts/kconfig/expr.o
  LEX     scripts/kconfig/lexer.lex.c
  YACC    scripts/kconfig/parser.tab.[ch]
  HOSTCC  scripts/kconfig/lexer.lex.o
  HOSTCC  scripts/kconfig/parser.tab.o
  HOSTCC  scripts/kconfig/preprocess.o
  HOSTCC  scripts/kconfig/symbol.o
  HOSTCC  scripts/kconfig/util.o
  HOSTLD  scripts/kconfig/conf
*** Default configuration is based on 'x86_64_defconfig'
#
# configuration written to .config
#

dileks@iniza:~/src/linux-kernel/linux$ scripts/config -m TEST_BITOPS

dileks@iniza:~/src/linux-kernel/linux$ $MAKE $MAKE_OPTS C=1 W=1 lib/test_bitops.ko
scripts/kconfig/conf  --syncconfig Kconfig
  SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
  SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_32.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_64.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_x32.h
  HOSTCC  arch/x86/tools/relocs_32.o
  HOSTCC  arch/x86/tools/relocs_64.o
  HOSTCC  arch/x86/tools/relocs_common.o
  HOSTLD  arch/x86/tools/relocs
  HOSTCC  scripts/selinux/genheaders/genheaders
  HOSTCC  scripts/selinux/mdp/mdp
  HOSTCC  scripts/kallsyms
  HOSTCC  scripts/sorttable
  HOSTCC  scripts/asn1_compiler
  HOSTCC  scripts/extract-cert
  WRAP    arch/x86/include/generated/uapi/asm/bpf_perf_event.h
  WRAP    arch/x86/include/generated/uapi/asm/errno.h
  WRAP    arch/x86/include/generated/uapi/asm/fcntl.h
  WRAP    arch/x86/include/generated/uapi/asm/ioctl.h
  WRAP    arch/x86/include/generated/uapi/asm/ioctls.h
  WRAP    arch/x86/include/generated/uapi/asm/ipcbuf.h
  WRAP    arch/x86/include/generated/uapi/asm/param.h
  WRAP    arch/x86/include/generated/uapi/asm/poll.h
  WRAP    arch/x86/include/generated/uapi/asm/resource.h
  WRAP    arch/x86/include/generated/uapi/asm/socket.h
  WRAP    arch/x86/include/generated/uapi/asm/sockios.h
  WRAP    arch/x86/include/generated/uapi/asm/termbits.h
  WRAP    arch/x86/include/generated/uapi/asm/termios.h
  WRAP    arch/x86/include/generated/uapi/asm/types.h
  WRAP    arch/x86/include/generated/asm/early_ioremap.h
  WRAP    arch/x86/include/generated/asm/export.h
  WRAP    arch/x86/include/generated/asm/mcs_spinlock.h
  WRAP    arch/x86/include/generated/asm/dma-contiguous.h
  WRAP    arch/x86/include/generated/asm/mm-arch-hooks.h
  WRAP    arch/x86/include/generated/asm/mmiowb.h
  UPD     include/config/kernel.release
  UPD     include/generated/uapi/linux/version.h
  UPD     include/generated/utsrelease.h
  CHECK   scripts/mod/empty.c
  CC      scripts/mod/empty.o
  HOSTCC  scripts/mod/mk_elfconfig
  MKELF   scripts/mod/elfconfig.h
  HOSTCC  scripts/mod/modpost.o
  CC      scripts/mod/devicetable-offsets.s
  UPD     scripts/mod/devicetable-offsets.h
  HOSTCC  scripts/mod/file2alias.o
  HOSTCC  scripts/mod/sumversion.o
  HOSTLD  scripts/mod/modpost
  CC      kernel/bounds.s
  UPD     include/generated/bounds.h
  UPD     include/generated/timeconst.h
  CC      arch/x86/kernel/asm-offsets.s
  UPD     include/generated/asm-offsets.h
  CALL    scripts/checksyscalls.sh
  CALL    scripts/atomic/check-atomics.sh
  DESCEND  objtool
  HOSTCC   /home/dileks/src/linux-kernel/linux/tools/objtool/fixdep.o
  HOSTLD   /home/dileks/src/linux-kernel/linux/tools/objtool/fixdep-in.o
  LINK     /home/dileks/src/linux-kernel/linux/tools/objtool/fixdep
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/exec-cmd.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/help.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/pager.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/parse-options.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/run-command.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/sigchain.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/subcmd-config.o
  LD       /home/dileks/src/linux-kernel/linux/tools/objtool/libsubcmd-in.o
  AR       /home/dileks/src/linux-kernel/linux/tools/objtool/libsubcmd.a
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/arch/x86/decode.o
  LD       /home/dileks/src/linux-kernel/linux/tools/objtool/arch/x86/objtool-in.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/builtin-check.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/builtin-orc.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/check.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/orc_gen.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/orc_dump.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/elf.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/special.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/objtool.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/libstring.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/libctype.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/str_error_r.o
  CC       /home/dileks/src/linux-kernel/linux/tools/objtool/librbtree.o
  LD       /home/dileks/src/linux-kernel/linux/tools/objtool/objtool-in.o
  LINK     /home/dileks/src/linux-kernel/linux/tools/objtool/objtool
  CHECK   lib/test_bitops.c
/home/dileks/src/llvm-toolchain/install/lib/clang/10.0.1/include/stdarg.h:26:5: warning: undefined preprocessor identifier '__STDC_VERSION__'
/home/dileks/src/llvm-toolchain/install/lib/clang/10.0.1/include/stdarg.h:26:36: warning: undefined preprocessor identifier '__cplusplus'
  CC [M]  lib/test_bitops.o
  MODPOST 1 modules
  CC [M]  lib/test_bitops.mod.o
  LD [M]  lib/test_bitops.ko

dileks@iniza:~/src/linux-kernel/linux$ objdump -S -d lib/test_bitops.ko

lib/test_bitops.ko:     file format elf64-x86-64

Disassembly of section .init.text:

0000000000000000 <init_module>:
   0:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
   7:   31 c0                   xor    %eax,%eax
   9:   e8 00 00 00 00          callq  e <init_module+0xe>
   e:   f0 80 0d 00 00 00 00    lock orb $0x10,0x0(%rip)        # 16 <init_module+0x16>
  15:   10 
  16:   f0 80 0d 00 00 00 00    lock orb $0x80,0x0(%rip)        # 1e <init_module+0x1e>
  1d:   80 
  1e:   f0 80 0d 00 00 00 00    lock orb $0x8,0x0(%rip)        # 26 <init_module+0x26>
  25:   08 
  26:   f0 80 0d 00 00 00 00    lock orb $0x80,0x0(%rip)        # 2e <init_module+0x2e>
  2d:   80 
  2e:   f0 80 0d 00 00 00 00    lock orb $0x1,0x0(%rip)        # 36 <init_module+0x36>
  35:   01 
  36:   31 c0                   xor    %eax,%eax
  38:   c3                      retq   

Disassembly of section .exit.text:

0000000000000000 <cleanup_module>:
   0:   f0 80 25 00 00 00 00    lock andb $0xef,0x0(%rip)        # 8 <cleanup_module+0x8>
   7:   ef 
   8:   f0 80 25 00 00 00 00    lock andb $0x7f,0x0(%rip)        # 10 <cleanup_module+0x10>
   f:   7f 
  10:   f0 80 25 00 00 00 00    lock andb $0xf7,0x0(%rip)        # 18 <cleanup_module+0x18>
  17:   f7 
  18:   f0 80 25 00 00 00 00    lock andb $0x7f,0x0(%rip)        # 20 <cleanup_module+0x20>
  1f:   7f 
  20:   f0 80 25 00 00 00 00    lock andb $0xfe,0x0(%rip)        # 28 <cleanup_module+0x28>
  27:   fe 
  28:   be ff 00 00 00          mov    $0xff,%esi
  2d:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  34:   e8 00 00 00 00          callq  39 <cleanup_module+0x39>
  39:   3d ff 00 00 00          cmp    $0xff,%eax
  3e:   74 10                   je     50 <cleanup_module+0x50>
  40:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  47:   89 c6                   mov    %eax,%esi
  49:   31 c0                   xor    %eax,%eax
  4b:   e8 00 00 00 00          callq  50 <cleanup_module+0x50>
  50:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
  57:   31 c0                   xor    %eax,%eax
  59:   e9 00 00 00 00          jmpq   5e <__UNIQUE_ID_description39+0x1d>
dileks commented 4 years ago

Tested v5 on Debian/testing AMD64 with selfmade llvm-toolchain (LLVM/Clang/LLD) v10.0.1+git92d5c1be9ee9

Please add: Tested-by: Sedat Dilek sedat.dilek@gmail.com

For details see < https://github.com/ClangBuiltLinux/linux/issues/961#issuecomment-626104287>

Thanks to all involved people.

On Sat, May 9, 2020 at 2:42 AM Nick Desaulniers notifications@github.com wrote:

great, thanks for the reviews + testing!

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/ClangBuiltLinux/linux/issues/961#issuecomment-626076928, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAFQTSC5XQ7HARRJ2XWIG3TRQSRIXANCNFSM4LXX75TQ .

nickdesaulniers commented 4 years ago

accepted: https://ozlabs.org/~akpm/mmots/broken-out/x86-bitops-fix-build-regression.patch

dileks commented 4 years ago

Patch entered linux-next (next-20200518).

[1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20200518&id=21635de44da73491c34a8e7d710c363a95147aac

dileks commented 4 years ago

Now upstream.

[1] https://git.kernel.org/linus/c071b0f11e7fb944525b12c80e728af69648d967

dileks commented 4 years ago

@jbrandeb

Now upstream:

"lib: make a test module with set/clear bit" https://git.kernel.org/linus/c348c16305280fe3e6c1186378f96c8634c149f9