| From 8ec3265f11ee910f8b66a4743cb2327fb1e32dcf Mon Sep 17 00:00:00 2001 |
| From: Michael Ellerman <mpe@ellerman.id.au> |
| Date: Thu, 6 Apr 2017 23:34:38 +1000 |
| Subject: [PATCH] powerpc/crypto/crc32c-vpmsum: Fix missing preempt_disable() |
| |
| commit 4749228f022893faf54a3dbc70796f78b7d4f342 upstream. |
| |
| 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> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/arch/powerpc/crypto/crc32c-vpmsum_glue.c b/arch/powerpc/crypto/crc32c-vpmsum_glue.c |
| index 411994551afc..f058e0c3e4d4 100644 |
| --- a/arch/powerpc/crypto/crc32c-vpmsum_glue.c |
| +++ b/arch/powerpc/crypto/crc32c-vpmsum_glue.c |
| @@ -33,10 +33,13 @@ static u32 crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len) |
| } |
| |
| if (len & ~VMX_ALIGN_MASK) { |
| + preempt_disable(); |
| pagefault_disable(); |
| enable_kernel_altivec(); |
| crc = __crc32c_vpmsum(crc, p, len & ~VMX_ALIGN_MASK); |
| + disable_kernel_altivec(); |
| pagefault_enable(); |
| + preempt_enable(); |
| } |
| |
| tail = len & VMX_ALIGN_MASK; |
| -- |
| 2.12.0 |
| |