From: Ming Lei <ming.lei@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Ewan D. Milne <emilne@xxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
}
