This patch fixes a reference count handling issue in the function
lpfc_bsg_hba_set_event(). In the branch
if (evt->reg_id == event_req->ev_reg_id), the function calls
lpfc_bsg_event_ref(), which increments the reference count of the
associated resource. However, in the subsequent branch
if (&evt->node == &phba->ct_ev_waiters), a new evt is allocated, but the
old evt should be released at this point. Failing to do so could lead to
issues.
To resolve this issue, we added a release instruction at the beginning of
the next branch if (&evt->node == &phba->ct_ev_waiters), ensuring that the
resources allocated in the previous branch are properly released, thereby
preventing a reference count leak.
This bug was identified by an experimental static analysis tool developed
by our team. The tool specializes in analyzing reference count operations
and detecting potential issues where resources are not properly managed.
In this case, the tool flagged the missing release operation as a
potential problem, which led to the development of this patch.
Fixes: 4cc0e56e977f ("[SCSI] lpfc 8.3.8: (BSG3) Modify BSG commands to operate asynchronously")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Qiu-ji Chen <chenqiuji666@xxxxxxxxx>
---
drivers/scsi/lpfc/lpfc_bsg.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/scsi/lpfc/lpfc_bsg.c b/drivers/scsi/lpfc/lpfc_bsg.c
index 85059b83ea6b..3a65270c5584 100644
--- a/drivers/scsi/lpfc/lpfc_bsg.c
+++ b/drivers/scsi/lpfc/lpfc_bsg.c
@@ -1200,6 +1200,9 @@ lpfc_bsg_hba_set_event(struct bsg_job *job)
spin_unlock_irqrestore(&phba->ct_ev_lock, flags);
if (&evt->node == &phba->ct_ev_waiters) {
+ spin_lock_irqsave(&phba->ct_ev_lock, flags);
+ lpfc_bsg_event_unref(evt);
+ spin_unlock_irqrestore(&phba->ct_ev_lock, flags);
/* no event waiting struct yet - first call */
dd_data = kmalloc(sizeof(struct bsg_job_data), GFP_KERNEL);
if (dd_data == NULL) {
--
2.34.1
