On Thu, Nov 07, 2019 at 18:08:40 +0100, Kamil Rytarowski wrote: > On 07.11.2019 16:45, Kamil Rytarowski wrote: > > On 07.11.2019 16:26, Martin Husemann wrote: > >> On Thu, Nov 07, 2019 at 02:53:08PM +0100, Kamil Rytarowski wrote: > >>> On 07.11.2019 14:25, Valery Ushakov wrote: > >>>> If the sanitizer does complain about other uses, there is little point > >>>> in fixing one instance and not the others. > >>> > >>> We already agreed with Christos that this is appeasing of GCC. If you > >>> want to scan the whole kernel (or whole C) file for more occurrences of > >>> violations - please go for it. > >> > >> No. The commit needs to be reverted, and then > >> > >> a) either the root cause for the unaligned address be fixed or > >> b) some other means be found to make the sanitizer shut up > >> > >> As uwe said: papering over a tiny detail that *never* hits in the real > >> world but potentialy hiding a real issue is not the way to go. > >> > > > > I don't have a readily available reproducer locally but it was breaking > > syzbot from booting after the switch to gcc8. I will fix it differently > > aligning the whole struct (so the same approach as we use in userland) > > and backout this change. > > > > Please review: > > http://netbsd.org/~kamil/patch-00194-disklabel-alignment.txt > > This patch works for me.
What happens if you change check_label_magic() to use direct member accesses (as the code did before xtos change it) instead of memcmp? Does that shup up the sanitizer? I assume it should as it doesn't complain about other member accesses. I'd strongly prefer this change for now. -uwe