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authorMing Lei <ming.lei@redhat.com>2019-07-12 04:08:19 +0200
committerMartin K. Petersen <martin.petersen@oracle.com>2019-07-17 04:39:24 +0200
commitf9b0530fa02e0c73f31a49ef743e8f44eb8e32cc (patch)
treeca8a8951347a3b5bbba448d80269476271ed064b /drivers
parentscsi: sd_zbc: Fix compilation warning (diff)
downloadlinux-f9b0530fa02e0c73f31a49ef743e8f44eb8e32cc.tar.xz
linux-f9b0530fa02e0c73f31a49ef743e8f44eb8e32cc.zip
scsi: core: Fix race on creating sense cache
When scsi_init_sense_cache(host) is called concurrently from different hosts, each code path may find that no cache has been created and allocate a new one. The lack of locking can lead to potentially overriding a cache allocated by a different host. Fix the issue by moving 'mutex_lock(&scsi_sense_cache_mutex)' before scsi_select_sense_cache(). Fixes: 0a6ac4ee7c21 ("scsi: respect unchecked_isa_dma for blk-mq") Cc: Stable <stable@vger.kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Ewan D. Milne <emilne@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/scsi/scsi_lib.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index ae1c989ef08e..420e2354b36b 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -84,11 +84,11 @@ int scsi_init_sense_cache(struct Scsi_Host *shost)
struct kmem_cache *cache;
int ret = 0;
+ mutex_lock(&scsi_sense_cache_mutex);
cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
if (cache)
- return 0;
+ goto exit;
- mutex_lock(&scsi_sense_cache_mutex);
if (shost->unchecked_isa_dma) {
scsi_sense_isadma_cache =
kmem_cache_create("scsi_sense_cache(DMA)",
@@ -104,7 +104,7 @@ int scsi_init_sense_cache(struct Scsi_Host *shost)
if (!scsi_sense_cache)
ret = -ENOMEM;
}
-
+ exit:
mutex_unlock(&scsi_sense_cache_mutex);
return ret;
}