This is a note to let you know that I've just added the patch titled
scsi: libfc: Skip additional kref updating work event
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-libfc-skip-additional-kref-updating-work-event.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2d588689106934aab2ad191c283f34c6042d415c
Author: Javed Hasan <jhasan@xxxxxxxxxxx>
Date: Fri Jun 26 02:49:59 2020 -0700
scsi: libfc: Skip additional kref updating work event
[ Upstream commit 823a65409c8990f64c5693af98ce0e7819975cba ]
When an rport event (RPORT_EV_READY) is updated without work being queued,
avoid taking an additional reference.
This issue was leading to memory leak. Trace from KMEMLEAK tool:
unreferenced object 0xffff8888259e8780 (size 512):
comm "kworker/2:1", jiffies 4433237386 (age 113021.971s)
hex dump (first 32 bytes):
58 0a ec cf 83 88 ff ff 00 00 00 00 00 00 00 00
01 00 00 00 08 00 00 00 13 7d f0 1e 0e 00 00 10
backtrace:
[<000000006b25760f>] fc_rport_recv_req+0x3c6/0x18f0 [libfc]
[<00000000f208d994>] fc_lport_recv_els_req+0x120/0x8a0 [libfc]
[<00000000a9c437b8>] fc_lport_recv+0xb9/0x130 [libfc]
[<00000000a9c437b8>] fc_lport_recv+0xb9/0x130 [libfc]
[<00000000ad5be37b>] qedf_ll2_process_skb+0x73d/0xad0 [qedf]
[<00000000e0eb6893>] process_one_work+0x382/0x6c0
[<000000002dfd9e21>] worker_thread+0x57/0x5c0
[<00000000b648204f>] kthread+0x1a0/0x1c0
[<0000000072f5ab20>] ret_from_fork+0x35/0x40
[<000000001d5c05d8>] 0xffffffffffffffff
Below is the log sequence which leads to memory leak. Here we get the
RPORT_EV_READY and RPORT_EV_STOP back to back, which lead to overwrite the
event RPORT_EV_READY by event RPORT_EV_STOP. Because of this, kref_count
gets incremented by 1.
kernel: host0: rport fffce5: Received PLOGI request
kernel: host0: rport fffce5: Received PLOGI in INIT state
kernel: host0: rport fffce5: Port is Ready
kernel: host0: rport fffce5: Received PRLI request while in state Ready
kernel: host0: rport fffce5: PRLI rspp type 8 active 1 passive 0
kernel: host0: rport fffce5: Received LOGO request while in state Ready
kernel: host0: rport fffce5: Delete port
kernel: host0: rport fffce5: Received PLOGI request
kernel: host0: rport fffce5: Received PLOGI in state Delete - send busy
kernel: host0: rport fffce5: work event 3
kernel: host0: rport fffce5: lld callback ev 3
kernel: host0: rport fffce5: work delete
Link: https://lore.kernel.org/r/20200626094959.32151-1-jhasan@xxxxxxxxxxx
Reviewed-by: Girish Basrur <gbasrur@xxxxxxxxxxx>
Reviewed-by: Saurav Kashyap <skashyap@xxxxxxxxxxx>
Reviewed-by: Shyam Sundar <ssundar@xxxxxxxxxxx>
Signed-off-by: Javed Hasan <jhasan@xxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
index f39d2d62b002f..2b3239765c249 100644
--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c
@@ -495,10 +495,11 @@ static void fc_rport_enter_delete(struct fc_rport_priv *rdata,
fc_rport_state_enter(rdata, RPORT_ST_DELETE);
- kref_get(&rdata->kref);
- if (rdata->event == RPORT_EV_NONE &&
- !queue_work(rport_event_queue, &rdata->event_work))
- kref_put(&rdata->kref, fc_rport_destroy);
+ if (rdata->event == RPORT_EV_NONE) {
+ kref_get(&rdata->kref);
+ if (!queue_work(rport_event_queue, &rdata->event_work))
+ kref_put(&rdata->kref, fc_rport_destroy);
+ }
rdata->event = event;
}
