Messages in this thread | | | Date | Wed, 3 Jan 2024 18:24:19 +0000 | From | Mark Brown <> | Subject | Re: [syzbot] [arm?] WARNING in do_sve_acc |
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On Wed, Jan 03, 2024 at 06:05:49PM +0000, Will Deacon wrote: > [+Broonie and Mark R as I'm sure we've seen this one before, possibly > in a report from Naresh? Was it a QEMU issue?]
It's been reported by the LKFT people, but it occurs with *extremely* low frequency, there's no reproducer and nothing showed up from code inspection by myself and Mark. The reports suggest it's been there since ~v5.15 (that's the oldest stable it was seen in and Linaro do still cover older), though Linaro's reports were conflating multiple potentially related symptoms so it's a little unclear what exactly was seen in what version.
I suspect to the extent it's qemu it's just that that's mostly where people are exercising SVE. This was shown with a userspace with SVE usage in glibc, I *think* that upgrading to a similar glibc version was what started Linaro seeing things too based on the release dates for the particular stable versions they mentioned but didn't get them to confirm yet.
I *might've* been able to show something with current code just before Christmas but the symptoms are a bit different, I was going to start looking when I get back.
> > Unfortunately, I don't have any reproducer for this issue yet.
Indeed...
> > compiler: aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> > pc : do_sve_acc+0x6c/0x10c arch/arm64/kernel/fpsimd.c:1394 > > lr : do_sve_acc+0x5c/0x10c arch/arm64/kernel/fpsimd.c:1391 [unhandled content-type:application/pgp-signature] | |