[core] More vertex buffer validation

[sagudev]

Connections
Fix #6799

Testing
CTS run in servo:

OK /_webgpu/webgpu/cts.https.html?q=webgpu:api,validation,capability_checks,limits,maxVertexAttributes:createRenderPipeline,at_over:*

    PASS [expected FAIL] subtest: :limitTest="atDefault";testValueName="overLimit";async=false
    PASS [expected FAIL] subtest: :limitTest="atDefault";testValueName="overLimit";async=true
    PASS [expected FAIL] subtest: :limitTest="underDefault";testValueName="overLimit";async=false
    PASS [expected FAIL] subtest: :limitTest="underDefault";testValueName="overLimit";async=true
    PASS [expected FAIL] subtest: :limitTest="betweenDefaultAndMaximum";testValueName="overLimit";async=false
    PASS [expected FAIL] subtest: :limitTest="betweenDefaultAndMaximum";testValueName="overLimit";async=true
    PASS [expected FAIL] subtest: :limitTest="atMaximum";testValueName="overLimit";async=false
    PASS [expected FAIL] subtest: :limitTest="atMaximum";testValueName="overLimit";async=true

Checklist

• Run cargo fmt.
• Run taplo format.
• Run cargo clippy. If applicable, add:
  • --target wasm32-unknown-unknown
  • --target wasm32-unknown-emscripten
• Run cargo xtask test to run tests.
• Add change to CHANGELOG.md. See simple instructions inside file.

[sagudev]

@abey79 could you test if this raises error where you expected to?

[abey79]

TL;DR: yes, my offending code now panics 👍🏻

edit: on second thought, that message seems wrong: the stride is 8 bytes and the attributes are 32 bytes in total, which is indeed non-compliant (the stride is allowed to be greater, not smaller).

Can be reproduced with this branch (https://github.com/abey79/vsvg/tree/antoine/wgpu-fix-test), which patches wgpu to this commit.

❯ cargo run -p whiskers-web-demo             
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.11s
     Running `target/debug/whiskers-web-demo`
thread 'main' panicked at /Users/hhip/.cargo/git/checkouts/wgpu-53e70f8674b08dd4/b92e624/wgpu/src/backend/wgpu_core.rs:1302:26:
wgpu error: Validation Error

Caused by:
  In Device::create_render_pipeline, label = 'line pipeline'
    Vertex buffer 0 stride 32 exceeds the limit 8


note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread 'main' panicked at library/core/src/panicking.rs:221:5:
panic in a function that cannot unwind
stack backtrace:
   0:        0x1015b9e8c - std::backtrace_rs::backtrace::libunwind::trace::hbebc8679d47bdc2c
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/../../backtrace/src/backtrace/libunwind.rs:116:5
   1:        0x1015b9e8c - std::backtrace_rs::backtrace::trace_unsynchronized::h3a2e9637943241aa
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:        0x1015b9e8c - std::sys::backtrace::_print_fmt::he430849680584674
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/sys/backtrace.rs:65:5
   3:        0x1015b9e8c - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h243268f17d714c7f
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/sys/backtrace.rs:40:26
   4:        0x1015da168 - core::fmt::rt::Argument::fmt::h0d339881c25f3c31
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/core/src/fmt/rt.rs:173:76
   5:        0x1015da168 - core::fmt::write::hb3cfb8a30e72d7ff
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/core/src/fmt/mod.rs:1182:21
   6:        0x1015b6e8c - std::io::Write::write_fmt::hfb2314975de9ecf1
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/io/mod.rs:1827:15
   7:        0x1015bafec - std::sys::backtrace::BacktraceLock::print::he14461129ccbfef5
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/sys/backtrace.rs:43:9
   8:        0x1015bafec - std::panicking::default_hook::{{closure}}::h14c7718ccf39d316
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/panicking.rs:269:22
   9:        0x1015bac10 - std::panicking::default_hook::hc62e60da3be2f352
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/panicking.rs:296:9
  10:        0x1015bbab0 - std::panicking::rust_panic_with_hook::h09e8a656f11e82b2
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/panicking.rs:800:13
  11:        0x1015bb3d8 - std::panicking::begin_panic_handler::{{closure}}::h1230eb3cc91b241c
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/panicking.rs:667:13
  12:        0x1015ba318 - std::sys::backtrace::__rust_end_short_backtrace::hc3491307aceda2c2
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/sys/backtrace.rs:168:18
  13:        0x1015bb0c8 - rust_begin_unwind
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/std/src/panicking.rs:665:5
  14:        0x10164dbbc - core::panicking::panic_nounwind_fmt::runtime::h5290ab2b4897aadc
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/core/src/panicking.rs:112:18
  15:        0x10164dbbc - core::panicking::panic_nounwind_fmt::h91ee161184879b56
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/core/src/panicking.rs:122:5
  16:        0x10164dc34 - core::panicking::panic_nounwind::heab7ebe7a6cd845c
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/core/src/panicking.rs:221:5
  17:        0x10164ddac - core::panicking::panic_cannot_unwind::hedc43d82620205bf
                               at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library/core/src/panicking.rs:309:5
  18:        0x1008ff94c - winit::platform_impl::macos::app_state::ApplicationDelegate::app_did_finish_launching::h26a705a9210618bb
                               at /Users/hhip/.cargo/registry/src/index.crates.io-6f17d22bba15001f/objc2-0.5.2/src/macros/declare_class.rs:981:25
  19:        0x18767d360 - <unknown>
  20:        0x18770e20c - <unknown>
  21:        0x18770e154 - <unknown>
  22:        0x18764bf9c - <unknown>
  23:        0x188805fd4 - <unknown>
  24:        0x18b1f9c78 - <unknown>
  25:        0x18b1f9a28 - <unknown>
  26:        0x18b1f7e88 - <unknown>
  27:        0x18b1f7a90 - <unknown>
  28:        0x18882ec8c - <unknown>
  29:        0x18882ea84 - <unknown>
thread caused non-unwinding panic. aborting.
zsh: abort      cargo run -p whiskers-web-demo

[abey79]

Repeating my edit above for visibility: on second thought, that message seems wrong. The stride is 8 bytes and the attributes are 32 bytes in total, which is indeed non-compliant (the stride is allowed to be greater, not smaller).

[cwfitzgerald]

Looks good, some comments

[cwfitzgerald]

Nice!