Dear Maintainer,

While using proxmox 8 (arm64 port) and viewing the console of a kvm session in novnc the kvm
process regularly terminates.  Using gdb and installing symbols I have traced this to
libpixman-1-0

Thread 15 "SPICE Worker" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xfffab37ea3e0 (LWP 238200)]
0x0000fffff7ef913c in pixman_composite_src_8888_8888_asm_neon ()
    at ../../pixman/pixman-arma64-neon-asm.S:1331
Downloading source file /build/pixman-phIJcH/pixman-0.42.2/build/pixman/../../pixman/pixman-arma64-neon-asm.S
1331    ../../pixman/pixman-arma64-neon-asm.S: Directory not empty.


I am making the assumption that libpixman should not cause the segfault and the bug should be
reported here; if I should raise against kvm please advise

I experience this problem too.  In my case, I'm running Debian 12.9 and using virt-manager to view the VNC console of the VM.

I don't know who should own the bug, but I have also filed a bug report on pixman, where I included details of my findings.  It appears to be an out-of-bounds memory access on the source buffer, possibly in function arm_neon_blt.  https://gitlab.freedesktop.org/pixman/pixman/-/issues/119

I was able to work around the problem by removing the Spice display from my VM.  My VM had both Spice and VNC displays.  Even though I was using VNC, the presence of the Spice display seemed to cause the problem.

I fixed this upstream and it's now released in upstream version 0.46.0.
https://gitlab.freedesktop.org/pixman/pixman/-/commit/106323bc15c7eb89a033cf8ff38f52bca8a4b53c

Can we pull this fix from upstream?

Thanks,
--Joel

Hearing nothing from the maintainers, I've gone ahead and opened an MR with the upstream patch backported.

https://salsa.debian.org/xorg-team/lib/pixman/-/merge_requests/3

I hope this is helpful and gets us a step closer to closing this bug.

Thanks,
--Joel

I don't know if it's possible to get 0.46.0 (or 0.46.2) into Trixie, but
otherwise an update with MR 3 merged, would be appreciated :-)

While I don't use proxmox, for me (good) arm64 is important and that's
what an update would bring.
See also https://gitlab.freedesktop.org/pixman/pixman/-/issues/119
titled "Segfault in pixman_composite_src_8888_8888_asm_neon:1331".

Cheers,
  Diederik

Hello maintainers,

this segfault issue caused me a lot of headaches trying to run trixie on aarch64, and only after rebuilding the package on my own with the patch applied mentioned in this thread, the unreliability and constant crashing simply went away since.

It is unintelligible to me why this patch has not already been applied and propagated to trixie-backports for the benefit of all aarch64 users.

Please apply this patch to version 0.44.0-3 and provide updated packages to Debian users.

Thanks and regards,
Paul Seelig

Control: fixed -1 0.46.4-1

This bug was fixed with the upload of version 0.46.4-1, so update the
bug metadata accordingly.

I'm not closing this bug as a fix for Trixie, via a Stable update or
indeed via backports, sounds like 'a good idea'.