* [PATCH] powerpc/crypto/crct10dif-vpmsum: Fix missing preempt_disable()
@ 2017-04-19 5:07 Michael Ellerman
2017-04-20 0:10 ` Daniel Axtens
0 siblings, 1 reply; 3+ messages in thread
From: Michael Ellerman @ 2017-04-19 5:07 UTC (permalink / raw)
To: herbert; +Cc: linuxppc-dev, dja
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")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/crypto/crct10dif-vpmsum_glue.c | 3 +++
1 file changed, 3 insertions(+)
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;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc/crypto/crct10dif-vpmsum: Fix missing preempt_disable()
2017-04-19 5:07 [PATCH] powerpc/crypto/crct10dif-vpmsum: Fix missing preempt_disable() Michael Ellerman
@ 2017-04-20 0:10 ` Daniel Axtens
2017-04-20 5:37 ` Michael Ellerman
0 siblings, 1 reply; 3+ messages in thread
From: Daniel Axtens @ 2017-04-20 0:10 UTC (permalink / raw)
To: Michael Ellerman, herbert; +Cc: linuxppc-dev
Hi Michael,
> Fixes: b01df1c16c9a ("crypto: powerpc - Add CRC-T10DIF acceleration")
Thank you very much for doing this! (and my apologies for not doing it
myself!)
It all looks good to me.
I think an Ack is appropriate in these circumstances?
Acked-by: Daniel Axtens <dja@axtens.net>
Regards,
Daniel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc/crypto/crct10dif-vpmsum: Fix missing preempt_disable()
2017-04-20 0:10 ` Daniel Axtens
@ 2017-04-20 5:37 ` Michael Ellerman
0 siblings, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2017-04-20 5:37 UTC (permalink / raw)
To: Daniel Axtens, herbert; +Cc: linuxppc-dev
Daniel Axtens <dja@axtens.net> writes:
> Hi Michael,
>
>> Fixes: b01df1c16c9a ("crypto: powerpc - Add CRC-T10DIF acceleration")
>
> Thank you very much for doing this! (and my apologies for not doing it
> myself!)
No worries, the enable_altivec() API is ridiculous, I'm surprised we
ever get it right.
> It all looks good to me.
>
> I think an Ack is appropriate in these circumstances?
> Acked-by: Daniel Axtens <dja@axtens.net>
Thanks I've added that to v2.
cheers
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-04-20 5:37 UTC | newest]
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2017-04-19 5:07 [PATCH] powerpc/crypto/crct10dif-vpmsum: Fix missing preempt_disable() Michael Ellerman
2017-04-20 0:10 ` Daniel Axtens
2017-04-20 5:37 ` Michael Ellerman
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