Bug 222805 – Crash with "invalid opcode" if the CPU does not support SSE4

• Component: JavaScriptCore
• Status: RESOLVED DUPLICATE

[Alberto Garcia]

A user reported this crash with WebKitGTK 2.30.5 after opening www.avito.ru , selecting "Вход и регистрация" on the upper right corner and simply waiting for a few seconds.

(gdb) layout asm
>│0x7f00eb999254 <wasm_entry+56936>       roundss $0x2,%xmm0,%xmm1     │
 │0x7f00eb99925a <wasm_entry+56942>       movsbq 0x1(%r13,%r8,1),%r9   │
 │0x7f00eb999260 <wasm_entry+56948>       movss  %xmm1,0x0(%rbp,%r9,8) │
 │0x7f00eb999267 <wasm_entry+56955>       add    $0x3,%r8              │

This is a 64-bit build but the CPU is an old Intel Core 2 without SSE4 instructions. Disabling the JIT ("JavaScriptCoreUseJIT=0") seems to solve the problem.

I assume that there is no plan to support such old hardware, but is this simply a WONTFIX or should WebKit disable the JIT conditionally in these cases?

[Radar WebKit Bug Importer]

<rdar://problem/75363426>

[Carlos Garcia Campos]

Is this a duplicate of bug #222358?

[Michael Catanzaro]

(In reply to Alberto Garcia from comment #0)
> should WebKit disable the JIT conditionally in these cases?

That would be ideal.

[Michael Catanzaro]

*** Bug 222358 has been marked as a duplicate of this bug. ***

[Carlos Garcia Campos]

Can we just disable JIT when SSE4 is not available?

[Jernej Jakob]

JSC_useBaselineJIT=0 also fixes it for me. I have that exported in my environment .

[Michael Catanzaro]

(In reply to Carlos Garcia Campos from comment #5)
> Can we just disable JIT when SSE4 is not available?

Please, though I'm not sure how to test for that easily.

I checked and Fedora's baseline is SSE2. I guess Debian's is probably the same, so we would want to check for SSE3 really.

[Alberto Garcia]

(In reply to Michael Catanzaro from comment #7)
> I checked and Fedora's baseline is SSE2. I guess Debian's is probably the
> same, so we would want to check for SSE3 really.

It is, according to https://wiki.debian.org/ArchitectureSpecificsMemo#amd64:

"x86_64 with no optional extensions. The core specification includes MMX, SSE and SSE2 so these are OK, but SSE3 and up are not guaranteed."

[Michael Catanzaro]

This issue is basically the same as bug #220889 and there is a patch there with review feedback, so let's treat this one as the duplicate.

*** This bug has been marked as a duplicate of bug 220889 ***

[Michael Catanzaro]

Well, one possibility not contemplated in bug #220889 would be to automatically disable the JIT if the system does not support SSE4. If somebody wants to attempt that, we could reopen this one.