| Message ID | 1492666509-4568-1-git-send-email-mpe@ellerman.id.au (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
On Thu, Apr 20, 2017 at 03:35:09PM +1000, Michael Ellerman wrote: > In crct10dif_vpmsum() we call enable_kernel_altivec() without first > disabling preemption, which is not allowed. > > It used to be sufficient just to call pagefault_disable(), because that > also disabled preemption. But the two were decoupled in commit 8222dbe21e79 > ("sched/preempt, mm/fault: Decouple preemption from the page fault > logic") in mid 2015. > > The crct10dif-vpmsum code inherited this bug from the crc32c-vpmsum code > on which it was modelled. > > So add the missing preempt_disable/enable(). We should also call > disable_kernel_fp(), although it does nothing by default, there is a > debug switch to make it active and all enables should be paired with > disables. > > Fixes: b01df1c16c9a ("crypto: powerpc - Add CRC-T10DIF acceleration") > Acked-by: Daniel Axtens <dja@axtens.net> > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Patch applied. Thanks.
diff --git a/arch/powerpc/crypto/crct10dif-vpmsum_glue.c b/arch/powerpc/crypto/crct10dif-vpmsum_glue.c index bebfc329f746..02ea277863d1 100644 --- a/arch/powerpc/crypto/crct10dif-vpmsum_glue.c +++ b/arch/powerpc/crypto/crct10dif-vpmsum_glue.c @@ -44,10 +44,13 @@ static u16 crct10dif_vpmsum(u16 crci, unsigned char const *p, size_t len) if (len & ~VMX_ALIGN_MASK) { crc <<= 16; + preempt_disable(); pagefault_disable(); enable_kernel_altivec(); crc = __crct10dif_vpmsum(crc, p, len & ~VMX_ALIGN_MASK); + disable_kernel_altivec(); pagefault_enable(); + preempt_enable(); crc >>= 16; }
In crct10dif_vpmsum() we call enable_kernel_altivec() without first disabling preemption, which is not allowed. It used to be sufficient just to call pagefault_disable(), because that also disabled preemption. But the two were decoupled in commit 8222dbe21e79 ("sched/preempt, mm/fault: Decouple preemption from the page fault logic") in mid 2015. The crct10dif-vpmsum code inherited this bug from the crc32c-vpmsum code on which it was modelled. So add the missing preempt_disable/enable(). We should also call disable_kernel_fp(), although it does nothing by default, there is a debug switch to make it active and all enables should be paired with disables. Fixes: b01df1c16c9a ("crypto: powerpc - Add CRC-T10DIF acceleration") Acked-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- arch/powerpc/crypto/crct10dif-vpmsum_glue.c | 3 +++ 1 file changed, 3 insertions(+) v2: No change to the patch. Add dja's ack. Add linux-crypto to Cc.