Messages in this thread | | | Date | Tue, 23 Feb 2016 20:22:33 +0000 | From | Will Deacon <> | Subject | Re: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM) |
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On Tue, Feb 23, 2016 at 10:33:45PM +0300, Kirill A. Shutemov wrote: > On Tue, Feb 23, 2016 at 07:19:07PM +0100, Gerald Schaefer wrote: > > I'll check with Martin, maybe it is actually trivial, then we can > > do a quick test it to rule that one out. > > Oh. I found a bug in __split_huge_pmd_locked(). Although, not sure if it's > _the_ bug. > > pmdp_invalidate() is called for the wrong address :-/ > I guess that can be destructive on the architecture, right?
FWIW, arm64 ignores the address parameter for set_pmd_at, so this would only result in the TLBI nuking the wrong entries, which is going to be tricky to observe in practice given that we install a table entry immediately afterwards that maps the same pages. If s390 does more here (I see some magic asm using the address), that could be the answer...
Will
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