Re: [PATCH] x86emul: V{,P}{COMPRESS,EXPAND}* can (wrongly) trigger assertion
Andrew Cooper <[email protected]>
| Newsgroups | org.xenproject.lists.xen-devel |
|---|---|
| Message-ID | <[email protected]> |
On 16/07/2026 11:43 am, Jan Beulich wrote:
> AFL has pointed out that the op_bytes-is-not-0 assertion in common SIMD
> handling can trigger for these insns. Indeed when the (relevant part of)
> the controlling mask register is 0, no memory is accessed at all. Leave
> op_bytes unaltered in this case, to engage the short-circuiting in common
> SIMD handling when fault_suppression is true and op_bytes is 0.
>
> While there also correct a related typo in the test harness.
>
> Fixes: 65f82d4ce1ea ("x86emul: support AVX512{F,_VBMI2} compress/expand insns")
> Signed-off-by: Jan Beulich <[email protected]>
Acked-by: Andrew Cooper <[email protected]>
Is this local AFL testing? I'm slightly surprised that OSS-Fuzz hasn't
found this.