@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().
Changes from v5:
* remove sem_out label.
Changes from v4:
* use ERR_PTR series instead of adding another parameter in sg_add_sfp
Signed-off-by: Vaughan Cao <vaughan.cao@xxxxxxxxxx>
---
drivers/scsi/sg.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index dcbd95f..6bffe52 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -295,10 +295,6 @@ 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;
@@ -309,16 +305,16 @@ sg_open(struct inode *inode, struct file *filp)
/* retval is already provably zero at this point because of the
* check after retval = scsi_autopm_get_device(sdp->device))
*/
- else
- retval = -ENOMEM;
-
- if (retval) {
-sem_out:
+ else {
+ retval = PTR_ERR(sfp);
if (flags & O_EXCL) {
sdp->exclude = 0; /* undo if error */
up_write(&sdp->o_sem);
} else
up_read(&sdp->o_sem);
+ }
+
+ if (retval) {
error_out:
scsi_autopm_put_device(sdp->device);
sdp_put:
@@ -2047,7 +2043,7 @@ 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);
@@ -2062,6 +2058,10 @@ 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));
--
1.8.3.1
--
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