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authorVaughan Cao <vaughan.cao@oracle.com>2013-08-29 06:00:38 +0400
committerJames Bottomley <JBottomley@Parallels.com>2013-09-03 18:28:09 +0400
commite32c9e6300e3af659cbfe45e90a1e7dcd3572ada (patch)
tree2e924a5838335cbfca0cf52a0add8e38801773e2 /drivers/scsi/sg.c
parent00b2d9d6d05b56fc1d77071ff8ccbd2c65b48dec (diff)
downloadlinux-e32c9e6300e3af659cbfe45e90a1e7dcd3572ada.tar.xz
[SCSI] sg: checking sdp->detached isn't protected when open
@detached is set under the protection of sg_index_lock. Without getting the lock, new sfp will be added during sg removal and there is no chance for it to be picked out. So check with sg_index_lock held in sg_add_sfp(). Signed-off-by: Vaughan Cao <vaughan.cao@oracle.com> Acked-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi/sg.c')
-rw-r--r--drivers/scsi/sg.c17
1 files changed, 9 insertions, 8 deletions
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index d4af13269e85..64df1ab141e5 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -295,23 +295,20 @@ sg_open(struct inode *inode, struct file *filp)
if (flags & O_EXCL)
sdp->exclude = 1; /* used by release lock */
- if (sdp->detached) {
- retval = -ENODEV;
- goto sem_out;
- }
if (sfds_list_empty(sdp)) { /* no existing opens on this device */
sdp->sgdebug = 0;
q = sdp->device->request_queue;
sdp->sg_tablesize = queue_max_segments(q);
}
- if ((sfp = sg_add_sfp(sdp, dev)))
+ sfp = sg_add_sfp(sdp, dev);
+ if (!IS_ERR(sfp))
filp->private_data = sfp;
/* retval is already provably zero at this point because of the
* check after retval = scsi_autopm_get_device(sdp->device))
*/
else {
- retval = -ENOMEM;
-sem_out:
+ retval = PTR_ERR(sfp);
+
if (flags & O_EXCL) {
sdp->exclude = 0; /* undo if error */
up_write(&sdp->o_sem);
@@ -2045,7 +2042,7 @@ sg_add_sfp(Sg_device * sdp, int dev)
sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
if (!sfp)
- return NULL;
+ return ERR_PTR(-ENOMEM);
init_waitqueue_head(&sfp->read_wait);
rwlock_init(&sfp->rq_list_lock);
@@ -2060,6 +2057,10 @@ sg_add_sfp(Sg_device * sdp, int dev)
sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
sfp->parentdp = sdp;
write_lock_irqsave(&sg_index_lock, iflags);
+ if (sdp->detached) {
+ write_unlock_irqrestore(&sg_index_lock, iflags);
+ return ERR_PTR(-ENODEV);
+ }
list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
write_unlock_irqrestore(&sg_index_lock, iflags);
SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));