lkml.org 
[lkml]   [2014]   [Dec]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] 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>

---

I encountered this problem with a QLogic QLE2672 FC HBA using qla2xxx.
On my system, this would trigger BUG_ON(atomic_read(&bio->bi_remaining) <= 0)
in bio_endio(), or a general protection fault in __sg_free_table()
trying to free prot_sdb, or any number of other weird random problems.
All of this was caused by cmd->prot_sdb pointing to the wrong memory.
To see how the memory is allocated, refer to scsi_mq_setup_tags() in
scsi_lib.c.

For inclusion in 3.19, 3.18.x, and 3.17.x.

--- linux-3.18.0/drivers/scsi/scsi_lib.c.orig 2014-12-08 16:23:28.000000000 -0500
+++ linux-3.18.0/drivers/scsi/scsi_lib.c 2014-12-08 16:24:00.000000000 -0500
@@ -1829,7 +1829,9 @@ static int scsi_mq_prep_fn(struct reques

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 =


\
 
 \ /
  Last update: 2014-12-09 00:01    [W:0.054 / U:1.068 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site