On 2022-09-25 00:35, debian-bug-rep...@p0358.net wrote: > Hello, sorry for delayed response, I've managed to collect and analyze a few > coredump files with valid symbols (I installed libc6-dbg and dpkg-dev, and > pointed gdb at Debian's debuginfod server, also used apt-get source to get > the sources for libc6).
Thanks a lot for your work. With more data, it's way easier to understand the issue. > It seems there are at least 3-4 distinct places it crashes at, two places at > memchr-avx2.S, one at strlen-avx2.S, and potentially one at > syscall-template.S, although that last one may be just some kind of kill > signal redirect. The failing places in memchr-avx2.S and strlen-avx2.S points to BMI2 (bit manipulation instructions) which have been introduced in the AVX2 code, which should not have happened. The syscall-template.S is likely code that catches the signal to display a message and then re-emit it. > It does seem in case of this SIGILL there's no additional stack trace, also > the path containing ".." seems to cause the source code resolution to fail, > but still the debug symbols seem to show the file source and line, so it > should hopefully help see what exactly fails. > > I'm yet to try rebooting with microcode package installed though (I'll soon > check it and update on whether it helps, but even if it does, one without > bootable system first won't get a chance to install it; I'm a bit curious > how these changes did trigger this, given all these years it didn't happen > to occur before) I agree with you that this should be fixed without a microcode update, I am going to report that issue upstream and we'll get the fix in the Debian package. Now that we understood the bug, I actually find strange that the microcode update is fixing this, it looks like that the BMI2 instructions support has been added in a microcode update. Would it be possible to give the output of /proc/cpuinfo with and without the microcode update applied? Regards Aurelien -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurel...@aurel32.net http://www.aurel32.net
