lkml.org 
[lkml]   [2013]   [Oct]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3.8 58/81] esp_scsi: Fix tag state corruption when autosensing.
Date
3.8.13.12 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: "David S. Miller" <davem@davemloft.net>

[ Upstream commit 21af8107f27878813d0364733c0b08813c2c192a ]

Meelis Roos reports a crash in esp_free_lun_tag() in the presense
of a disk which has died.

The issue is that when we issue an autosense command, we do so by
hijacking the original command that caused the check-condition.

When we do so we clear out the ent->tag[] array when we issue it via
find_and_prep_issuable_command(). This is so that the autosense
command is forced to be issued non-tagged.

That is problematic, because it is the value of ent->tag[] which
determines whether we issued the original scsi command as tagged
vs. non-tagged (see esp_alloc_lun_tag()).

And that, in turn, is what trips up the sanity checks in
esp_free_lun_tag(). That function needs the original ->tag[] values
in order to free up the tag slot properly.

Fix this by remembering the original command's tag values, and
having esp_alloc_lun_tag() and esp_free_lun_tag() use them.

Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
drivers/scsi/esp_scsi.c | 14 ++++++++------
drivers/scsi/esp_scsi.h | 1 +
2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index 34552bf..55548dc 100644
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -530,7 +530,7 @@ static int esp_need_to_nego_sync(struct esp_target_data *tp)
static int esp_alloc_lun_tag(struct esp_cmd_entry *ent,
struct esp_lun_data *lp)
{
- if (!ent->tag[0]) {
+ if (!ent->orig_tag[0]) {
/* Non-tagged, slot already taken? */
if (lp->non_tagged_cmd)
return -EBUSY;
@@ -564,9 +564,9 @@ static int esp_alloc_lun_tag(struct esp_cmd_entry *ent,
return -EBUSY;
}

- BUG_ON(lp->tagged_cmds[ent->tag[1]]);
+ BUG_ON(lp->tagged_cmds[ent->orig_tag[1]]);

- lp->tagged_cmds[ent->tag[1]] = ent;
+ lp->tagged_cmds[ent->orig_tag[1]] = ent;
lp->num_tagged++;

return 0;
@@ -575,9 +575,9 @@ static int esp_alloc_lun_tag(struct esp_cmd_entry *ent,
static void esp_free_lun_tag(struct esp_cmd_entry *ent,
struct esp_lun_data *lp)
{
- if (ent->tag[0]) {
- BUG_ON(lp->tagged_cmds[ent->tag[1]] != ent);
- lp->tagged_cmds[ent->tag[1]] = NULL;
+ if (ent->orig_tag[0]) {
+ BUG_ON(lp->tagged_cmds[ent->orig_tag[1]] != ent);
+ lp->tagged_cmds[ent->orig_tag[1]] = NULL;
lp->num_tagged--;
} else {
BUG_ON(lp->non_tagged_cmd != ent);
@@ -667,6 +667,8 @@ static struct esp_cmd_entry *find_and_prep_issuable_command(struct esp *esp)
ent->tag[0] = 0;
ent->tag[1] = 0;
}
+ ent->orig_tag[0] = ent->tag[0];
+ ent->orig_tag[1] = ent->tag[1];

if (esp_alloc_lun_tag(ent, lp) < 0)
continue;
diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h
index 28e22ac..cd68805 100644
--- a/drivers/scsi/esp_scsi.h
+++ b/drivers/scsi/esp_scsi.h
@@ -271,6 +271,7 @@ struct esp_cmd_entry {
#define ESP_CMD_FLAG_AUTOSENSE 0x04 /* Doing automatic REQUEST_SENSE */

u8 tag[2];
+ u8 orig_tag[2];

u8 status;
u8 message;
--
1.8.1.2


\
 
 \ /
  Last update: 2013-10-29 21:21    [W:0.249 / U:4.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site