[wayland] crash in eglTerminate on program exit

[mcclure]

A test program that uses many wgpu features, but otherwise is fairly simple, segfaults on exit when run with winit 0.29. I don't know if this is a winit problem or a wgpu problem but wgpu_hal is in the gdb backtrace. I'm filing here first.

The GDB backtrace looks like

(gdb) bt

#0  0x00007ffff7fb1845 in ?? () from /lib/x86_64-linux-gnu/libwayland-client.so.0
#1  0x00007ffff7fb19a3 in ?? () from /lib/x86_64-linux-gnu/libwayland-client.so.0
#2  0x00007ffff7fb34d2 in wl_proxy_marshal_array_flags () from /lib/x86_64-linux-gnu/libwayland-client.so.0
#3  0x00007ffff7fb3f59 in wl_proxy_marshal_flags () from /lib/x86_64-linux-gnu/libwayland-client.so.0
#4  0x00007ffff46d9937 in ?? () from /lib/x86_64-linux-gnu/libEGL_mesa.so.0
#5  0x00007ffff46ce988 in ?? () from /lib/x86_64-linux-gnu/libEGL_mesa.so.0
#6  0x00007ffff46cee80 in ?? () from /lib/x86_64-linux-gnu/libEGL_mesa.so.0
#7  0x00007ffff46bc97c in ?? () from /lib/x86_64-linux-gnu/libEGL_mesa.so.0
#8  0x0000555556b7d8e2 in khronos_egl::{impl#98}::eglTerminate<libloading::safe::Library> (self=0x5555575d2cb0, 
    display=0x5555575dfc80)
    at /home/mcc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/khronos-egl-6.0.0/src/lib.rs:2321
#9  khronos_egl::Instance<khronos_egl::Dynamic<libloading::safe::Library, khronos_egl::EGL1_4>>::terminate<khronos_egl::Dynamic<libloading::safe::Library, khronos_egl::EGL1_4>> (self=0x5555575d2cb0, display=...)
    at /home/mcc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/khronos-egl-6.0.0/src/lib.rs:1181
#10 0x0000555556bfbbd4 in wgpu_hal::gles::egl::{impl#10}::drop (self=0x5555575dd9d8) at src/gles/egl.rs:621
#11 0x0000555556bc3177 in core::ptr::drop_in_place<wgpu_hal::gles::egl::Inner> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#12 0x0000555556acb27b in core::ptr::drop_in_place<core::cell::UnsafeCell<wgpu_hal::gles::egl::Inner>> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#13 0x0000555556ac893f in core::ptr::drop_in_place<lock_api::mutex::Mutex<parking_lot::raw_mutex::RawMutex, wgpu_hal::gles::egl::Inner>> () at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#14 0x0000555556ac9e0c in core::ptr::drop_in_place<wgpu_hal::gles::egl::Instance> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
--Type <RET> for more, q to quit, c to continue without paging--c

#15 0x0000555556acb3f3 in core::ptr::drop_in_place<core::option::Option<wgpu_hal::gles::egl::Instance>> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#16 0x000055555696e436 in core::ptr::drop_in_place<wgpu_core::instance::Instance> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#17 0x0000555556978a17 in core::ptr::drop_in_place<wgpu_core::global::Global<wgpu_core::identity::IdentityManagerFactory>> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#18 0x000055555696e634 in core::ptr::drop_in_place<wgpu::backend::direct::Context> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#19 0x000055555696ec70 in core::ptr::drop_in_place<dyn wgpu::context::DynContext> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#20 0x000055555686ea1a in alloc::sync::Arc<dyn wgpu::context::DynContext, alloc::alloc::Global>::drop_slow<dyn wgpu::context::DynContext, alloc::alloc::Global> (self=0x7ffffffeef10)
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/alloc/src/sync.rs:1749
#21 0x00005555568700d3 in alloc::sync::{impl#33}::drop<dyn wgpu::context::DynContext, alloc::alloc::Global> (
    self=0x7ffffffeef10) at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/alloc/src/sync.rs:2405
#22 0x0000555556972c8b in core::ptr::drop_in_place<alloc::sync::Arc<dyn wgpu::context::DynContext, alloc::alloc::Global>> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#23 0x0000555555a8ea47 in core::ptr::drop_in_place<wgpu::PipelineLayout> ()
    at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497
#24 0x0000555555b030a3 in wgpu_hello::run::{async_fn#0} () at src/main.rs:742
#25 0x0000555555a859e3 in pollster::block_on<wgpu_hello::run::{async_fn_env#0}> (fut=...)
    at /home/mcc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/pollster-0.3.0/src/lib.rs:128
#26 0x0000555555afc6fb in wgpu_hello::main () at src/main.rs:758

DETAILS/REPRO

I have a project https://github.com/mcclure/webgpu-tutorial-rs . As the name suggests, it is a (mostly finished) WebGPU tutorial application. It is based on the hello-triangle example.

As of a few days ago, commit a8e1516 was running wgpu 0.16 and winit 0.29-beta (a very early 0.29 beta, so that it had still the 0.28 API surface). This week, I attempted to upgrade. In commit 50c079e I upgraded to winit 0.29 final (while keeping wgpu fixed at 0.16). This had the effect of making the application segfault at close time. Because 0.16 is old, I upgraded to wgpu 0.18. This lead to a different problem #4630, fixed in PR #4635. Because I am trying to test with 0.18 I backported to 0.18 in PR #4649 which you can find the example code for in branch webgpu-tutorial-0.18-fork. You can test by checking out the webgpu-tutorial-0.18-fork branch and running cargo run (or commit 50c079e for the 0.16 version). Warning: When run successfully, this example has audio which currently may be somewhat loud.

Notice I select rwh_05 in Cargo.toml as directed by the wgpu matrix channel.

Platform

I am running with Rust 1.73.0 on Ubuntu 23.10 with Wayland and an almost entirely stock desktop environment. I am on a "Lenovo ThinkPad T14 Gen 3" with gpu "AMD Ryzen™ 5 PRO 6650U with Radeon™ Graphics × 12". The failure occurs 100% of the time. I have not tested on other platforms.

Both the 0.16 and 0.18 wgpu branch implicated wgpu_hal in the bt, though I don't think they were the same bt.

Expected behavior

In Rust, even if I do something wrong, I should get a panic with a clear error message rather than a segfault.

Note

I would be happy to file this bug on winit instead (since it was upgrading winit, not upgrading wgpu, that caused the problem) but I need to be able to plausibly say "I asked wgpu and they said it's not their fault (even though their frames are all over the gdb stack)".

[SludgePhD]

I've also observed these for a while. They can be avoided by requesting an instance with Backends::PRIMARY instead of the default Backends::all(), since they are caused by the GL backend.

[mcclure]

I tested and this problem is Wayland exclusive. If I log out, log back in to "Ubuntu with xorg", and repeat the tests, I do not get the crash in either 0.16 or 0.18.

[mcclure]

They can be avoided by requesting an instance with Backends::PRIMARY instead of the default Backends::all(), since they are caused by the GL backend.

Since not all systems have Vulkan, surely you want to include support for the GL backend?

[SludgePhD]

Since not all systems have Vulkan, surely you want to include support for the GL backend?

Yeah, YMMV. All systems I care about do support Vulkan, and I believe the GL backend has some other bugs too, so turning it off made sense.

[Wumpf]

Issue still happens in 0.20:

• https://github.com/gfx-rs/wgpu/issues/5655

Didn't happen in 0.19 because of another bug :/