From: Ming Lei ming.lei@redhat.com
commit f9b0530fa02e0c73f31a49ef743e8f44eb8e32cc upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/scsi/scsi_lib.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -71,11 +71,11 @@ int scsi_init_sense_cache(struct Scsi_Ho 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)", @@ -91,7 +91,7 @@ int scsi_init_sense_cache(struct Scsi_Ho if (!scsi_sense_cache) ret = -ENOMEM; } - + exit: mutex_unlock(&scsi_sense_cache_mutex); return ret; }