sym53c8xx: Fix NULL pointer dereference in slave_destroy

commit cced5041ed5a2d1352186510944b0ddfbdbe4c0b upstream.

sym53c8xx_slave_destroy unconditionally assumes that sym53c8xx_slave_alloc has
succesesfully allocated a sym_lcb. This can lead to a NULL pointer dereference
(exposed by commit 4e6c82b).

Signed-off-by: Stratos Psomadakis <psomas@gentoo.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index 45374d66d26a4268ae9a765d45687c8a0c02c29a..c19ca5e35baa164545a28fc7e2bc853c0b0740a6 100644 (file)
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -837,6 +837,10 @@ static void sym53c8xx_slave_destroy(struct scsi_device *sdev)
        struct sym_lcb *lp = sym_lp(tp, sdev->lun);
        unsigned long flags;
 
+       /* if slave_alloc returned before allocating a sym_lcb, return */
+       if (!lp)
+               return;
+
        spin_lock_irqsave(np->s.host->host_lock, flags);
 
        if (lp->busy_itlq || lp->busy_itl) {