From: David Miller <davem@xxxxxxxxxxxxx>
Date: Mon, 29 Jul 2013 15:32:23 -0700 (PDT)
> Therefore I think the fix is going to involve adding a member to
> "struct esp_cmd_entry" called "->orig_tag[]" so that we can see what
> the original tag[] values were at esp_alloc_lun_tag() time.
Please try this patch:
====================
esp_scsi: Fix tag state corruption when autosensing.
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@xxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
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;
--
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