[SCSI] fix race in scsi_target_reap
This patch (as1357) fixes a race in SCSI target allocation and
release. Putting a target in the STARGET_DEL state isn't protected by
the host lock, so an old target structure could be reused by a new
device even though it's about to be deleted. The cure is to change
the state while still holding the host lock.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index c992ecf..a77468c 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -492,19 +492,20 @@
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
unsigned long flags;
enum scsi_target_state state;
- int empty;
+ int empty = 0;
spin_lock_irqsave(shost->host_lock, flags);
state = starget->state;
- empty = --starget->reap_ref == 0 &&
- list_empty(&starget->devices) ? 1 : 0;
+ if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
+ empty = 1;
+ starget->state = STARGET_DEL;
+ }
spin_unlock_irqrestore(shost->host_lock, flags);
if (!empty)
return;
BUG_ON(state == STARGET_DEL);
- starget->state = STARGET_DEL;
if (state == STARGET_CREATED)
scsi_target_destroy(starget);
else