Messages in this thread | | | Date | Tue, 3 Oct 2023 09:28:33 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86/boot: Move x86_cache_alignment initialization to correct spot |
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* Nathan Chancellor <nathan@kernel.org> wrote:
> On Mon, Oct 02, 2023 at 03:00:45PM -0700, Dave Hansen wrote: > > c->x86_cache_alignment is initialized from c->x86_clflush_size. > > However, commit fbf6449f84bf moved c->x86_clflush_size initialization > > to later in boot without moving the c->x86_cache_alignment assignment. > > > > This presumably left c->x86_cache_alignment set to zero for longer > > than it should be. > > > > The result was an oops on 32-bit kernels while accessing a pointer > > at 0x20. The 0x20 came from accessing a structure member at offset > > 0x10 (buffer->cpumask) from a ZERO_SIZE_PTR=0x10. kmalloc() can > > evidently return ZERO_SIZE_PTR when it's given 0 as its alignment > > requirement. > > > > Move the c->x86_cache_alignment initialization to be after > > c->x86_clflush_size has an actual value. > > > > Fixes: fbf6449f84bf ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach") > > Cc: Adam Dunlap <acdunlap@google.com> > > Cc: Ingo Molnar <mingo@kernel.org> > > Cc: Jacob Xu <jacobhxu@google.com> > > Link: https://lore.kernel.org/all/20231002200426.GA4127272@dev-arch.thelio-3990X/ > > Tested-by: Nathan Chancellor <nathan@kernel.org> > > Thanks for the quick fix!
Thanks for the quick testing - I've applied this fix on top of fbf6449f84bf in tip:x86/mm.
Dave, I've added your SOB - let me know if that's not OK:
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Thanks,
Ingo
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