This is a note to let you know that I've just added the patch titled
scsi: lpfc: Fix hard lockup when reading the rx_monitor from debugfs
to the 6.0-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-lpfc-fix-hard-lockup-when-reading-the-rx_monito.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b19c314c5776bbd982fe09a5a07ecefbc5d4d384
Author: Justin Tee <justin.tee@xxxxxxxxxxxx>
Date: Mon Oct 17 09:43:20 2022 -0700
scsi: lpfc: Fix hard lockup when reading the rx_monitor from debugfs
[ Upstream commit c44e50f4a0ec00c2298f31f91bc2c3e9bbd81c7e ]
During I/O and simultaneous cat of /sys/kernel/debug/lpfc/fnX/rx_monitor, a
hard lockup similar to the call trace below may occur.
The spin_lock_bh in lpfc_rx_monitor_report is not protecting from timer
interrupts as expected, so change the strength of the spin lock to _irq.
Kernel panic - not syncing: Hard LOCKUP
CPU: 3 PID: 110402 Comm: cat Kdump: loaded
exception RIP: native_queued_spin_lock_slowpath+91
[IRQ stack]
native_queued_spin_lock_slowpath at ffffffffb814e30b
_raw_spin_lock at ffffffffb89a667a
lpfc_rx_monitor_record at ffffffffc0a73a36 [lpfc]
lpfc_cmf_timer at ffffffffc0abbc67 [lpfc]
__hrtimer_run_queues at ffffffffb8184250
hrtimer_interrupt at ffffffffb8184ab0
smp_apic_timer_interrupt at ffffffffb8a026ba
apic_timer_interrupt at ffffffffb8a01c4f
[End of IRQ stack]
apic_timer_interrupt at ffffffffb8a01c4f
lpfc_rx_monitor_report at ffffffffc0a73c80 [lpfc]
lpfc_rx_monitor_read at ffffffffc0addde1 [lpfc]
full_proxy_read at ffffffffb83e7fc3
vfs_read at ffffffffb833fe71
ksys_read at ffffffffb83402af
do_syscall_64 at ffffffffb800430b
entry_SYSCALL_64_after_hwframe at ffffffffb8a000ad
Signed-off-by: Justin Tee <justin.tee@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221017164323.14536-2-justintee8345@xxxxxxxxx
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 03c21167fc85..c4960da4c1c4 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -8076,10 +8076,10 @@ u32 lpfc_rx_monitor_report(struct lpfc_hba *phba,
"IO_cnt", "Info", "BWutil(ms)");
}
- /* Needs to be _bh because record is called from timer interrupt
+ /* Needs to be _irq because record is called from timer interrupt
* context
*/
- spin_lock_bh(ring_lock);
+ spin_lock_irq(ring_lock);
while (*head_idx != *tail_idx) {
entry = &ring[*head_idx];
@@ -8123,7 +8123,7 @@ u32 lpfc_rx_monitor_report(struct lpfc_hba *phba,
if (cnt >= max_read_entries)
break;
}
- spin_unlock_bh(ring_lock);
+ spin_unlock_irq(ring_lock);
return cnt;
}
