From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@ozlabs.org
Cc: anton@samba.org
Subject: Re: powerpc/crypto/crc32c-vpmsum: Fix missing preempt_disable()
Date: Wed, 12 Apr 2017 13:39:19 +1000 (AEST) [thread overview]
Message-ID: <3w2qRC5Svjz9sNJ@ozlabs.org> (raw)
In-Reply-To: <1491485678-3444-1-git-send-email-mpe@ellerman.id.au>
On Thu, 2017-04-06 at 13:34:38 UTC, Michael Ellerman wrote:
> In crc32c_vpmsum() we call enable_kernel_altivec() without first
> disabling preemption, which is not allowed:
>
> WARNING: CPU: 9 PID: 2949 at ../arch/powerpc/kernel/process.c:277 enable_kernel_altivec+0x100/0x120
> Modules linked in: dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c vmx_crypto ...
> CPU: 9 PID: 2949 Comm: docker Not tainted 4.11.0-rc5-compiler_gcc-6.3.1-00033-g308ac7563944 #381
> ...
> NIP [c00000000001e320] enable_kernel_altivec+0x100/0x120
> LR [d000000003df0910] crc32c_vpmsum+0x108/0x150 [crc32c_vpmsum]
> Call Trace:
> 0xc138fd09 (unreliable)
> crc32c_vpmsum+0x108/0x150 [crc32c_vpmsum]
> crc32c_vpmsum_update+0x3c/0x60 [crc32c_vpmsum]
> crypto_shash_update+0x88/0x1c0
> crc32c+0x64/0x90 [libcrc32c]
> dm_bm_checksum+0x48/0x80 [dm_persistent_data]
> sb_check+0x84/0x120 [dm_thin_pool]
> dm_bm_validate_buffer.isra.0+0xc0/0x1b0 [dm_persistent_data]
> dm_bm_read_lock+0x80/0xf0 [dm_persistent_data]
> __create_persistent_data_objects+0x16c/0x810 [dm_thin_pool]
> dm_pool_metadata_open+0xb0/0x1a0 [dm_thin_pool]
> pool_ctr+0x4cc/0xb60 [dm_thin_pool]
> dm_table_add_target+0x16c/0x3c0
> table_load+0x184/0x400
> ctl_ioctl+0x2f0/0x560
> dm_ctl_ioctl+0x38/0x50
> do_vfs_ioctl+0xd8/0x920
> SyS_ioctl+0x68/0xc0
> system_call+0x38/0xfc
>
> 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.
>
> 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: 6dd7a82cc54e ("crypto: powerpc - Add POWER8 optimised crc32c")
> Cc: stable@vger.kernel.org # v4.8+
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Applied to powerpc fixes.
https://git.kernel.org/powerpc/c/4749228f022893faf54a3dbc70796f
cheers
prev parent reply other threads:[~2017-04-12 3:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-06 13:34 [PATCH] powerpc/crypto/crc32c-vpmsum: Fix missing preempt_disable() Michael Ellerman
2017-04-07 1:00 ` Daniel Axtens
2017-04-12 3:39 ` Michael Ellerman [this message]
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