scsi: fix random memory corruption with scsi-mq + T10 PI
This fixes random memory corruption triggered when all three of the
following are true:
* scsi-mq enabled
* T10 Protection Information (DIF) enabled
* SCSI host with sg_tablesize > SCSI_MAX_SG_SEGMENTS (128)
The symptoms of this bug are unpredictable memory corruption, BUG()s,
oopses, lockups, etc., any of which may appear to be completely
unrelated to the root cause.
Cc: <stable@vger.kernel.org> # 3.17.x, 3.18.x
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 43318d5..9ea95dd 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1918,7 +1918,9 @@
if (scsi_host_get_prot(shost)) {
cmd->prot_sdb = (void *)sg +
- shost->sg_tablesize * sizeof(struct scatterlist);
+ min_t(unsigned int,
+ shost->sg_tablesize, SCSI_MAX_SG_SEGMENTS) *
+ sizeof(struct scatterlist);
memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
cmd->prot_sdb->table.sgl =
