From 21af8107f27878813d0364733c0b08813c2c192a Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Thu, 1 Aug 2013 18:08:34 -0700 Subject: [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 Tested-by: Meelis Roos Signed-off-by: David S. Miller --- 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 34552bf1c023..55548dc5cec3 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 28e22acf87ea..cd68805e8d78 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; -- 2.20.1