[PATCH AUTOSEL 5.15 025/109] scsi: lpfc: Fix SCSI I/O completion and abort handler deadlock

Sasha Levin
2022-05-30T14:09:09Z

From: James Smart <jsmart2021@gmail.com>

[ Upstream commit 03cbbd7c2f5ee288f648f4aeedc765a181188553 ]

During stress I/O tests with 500+ vports, hard LOCKUP call traces are
observed.

CPU A:
native_queued_spin_lock_slowpath+0x192
_raw_spin_lock_irqsave+0x32
lpfc_handle_fcp_err+0x4c6
lpfc_fcp_io_cmd_wqe_cmpl+0x964
lpfc_sli4_fp_handle_cqe+0x266
__lpfc_sli4_process_cq+0x105
__lpfc_sli4_hba_process_cq+0x3c
lpfc_cq_poll_hdler+0x16
irq_poll_softirq+0x76
__softirqentry_text_start+0xe4
irq_exit+0xf7
do_IRQ+0x7f

CPU B:
native_queued_spin_lock_slowpath+0x5b
_raw_spin_lock+0x1c
lpfc_abort_handler+0x13e
scmd_eh_abort_handler+0x85
process_one_work+0x1a7
worker_thread+0x30
kthread+0x112
ret_from_fork+0x1f

Diagram of lockup:

CPUA CPUB
---- ----
lpfc_cmd->buf_lock
phba->hbalock
lpfc_cmd->buf_lock
phba->hbalock

Fix by reordering the taking of the lpfc_cmd->buf_lock and phba->hbalock in
lpfc_abort_handler routine so that it tries to take the lpfc_cmd->buf_lock
first before phba->hbalock.

Link: https://lore.kernel.org/r/20220412222008.126521-7-jsmart2021@gmail.com
Co-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/lpfc/lpfc_scsi.c | 33 +++++++++++++++------------------
1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 3d9175f1b678..8c79264a935b 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -5885,25 +5885,25 @@ lpfc_abort_handler(struct scsi_cmnd *cmnd)
if (!lpfc_cmd)
return ret;

- spin_lock_irqsave(&phba->hbalock, flags);
+ /* Guard against IO completion being called at same time */
+ spin_lock_irqsave(&lpfc_cmd->buf_lock, flags);
+
+ spin_lock(&phba->hbalock);
/* driver queued commands are in process of being flushed */
if (phba->hba_flag & HBA_IOQ_FLUSH) {
lpfc_printf_vlog(vport, KERN_WARNING, LOG_FCP,
"3168 SCSI Layer abort requested I/O has been "
"flushed by LLD.\n");
ret = FAILED;
- goto out_unlock;
+ goto out_unlock_hba;
}

- /* Guard against IO completion being called at same time */
- spin_lock(&lpfc_cmd->buf_lock);
-
if (!lpfc_cmd->pCmd) {
lpfc_printf_vlog(vport, KERN_WARNING, LOG_FCP,
"2873 SCSI Layer I/O Abort Request IO CMPL Status "
"x%x ID %d LUN %llu\n",
SUCCESS, cmnd->device->id, cmnd->device->lun);
- goto out_unlock_buf;
+ goto out_unlock_hba;
}

iocb = &lpfc_cmd->cur_iocbq;
@@ -5911,7 +5911,7 @@ lpfc_abort_handler(struct scsi_cmnd *cmnd)
pring_s4 = phba->sli4_hba.hdwq[iocb->hba_wqidx].io_wq->pring;
if (!pring_s4) {
ret = FAILED;
- goto out_unlock_buf;
+ goto out_unlock_hba;
}
spin_lock(&pring_s4->ring_lock);
}
@@ -5944,8 +5944,8 @@ lpfc_abort_handler(struct scsi_cmnd *cmnd)
"3389 SCSI Layer I/O Abort Request is pending\n");
if (phba->sli_rev == LPFC_SLI_REV4)
spin_unlock(&pring_s4->ring_lock);
- spin_unlock(&lpfc_cmd->buf_lock);
- spin_unlock_irqrestore(&phba->hbalock, flags);
+ spin_unlock(&phba->hbalock);
+ spin_unlock_irqrestore(&lpfc_cmd->buf_lock, flags);
goto wait_for_cmpl;
}

@@ -5966,15 +5966,13 @@ lpfc_abort_handler(struct scsi_cmnd *cmnd)
if (ret_val != IOCB_SUCCESS) {
/* Indicate the IO is not being aborted by the driver. */
lpfc_cmd->waitq = NULL;
- spin_unlock(&lpfc_cmd->buf_lock);
- spin_unlock_irqrestore(&phba->hbalock, flags);
ret = FAILED;
- goto out;
+ goto out_unlock_hba;
}

/* no longer need the lock after this point */
- spin_unlock(&lpfc_cmd->buf_lock);
- spin_unlock_irqrestore(&phba->hbalock, flags);
+ spin_unlock(&phba->hbalock);
+ spin_unlock_irqrestore(&lpfc_cmd->buf_lock, flags);

if (phba->cfg_poll & DISABLE_FCP_RING_INT)
lpfc_sli_handle_fast_ring_event(phba,
@@ -6009,10 +6007,9 @@ lpfc_abort_handler(struct scsi_cmnd *cmnd)
out_unlock_ring:
if (phba->sli_rev == LPFC_SLI_REV4)
spin_unlock(&pring_s4->ring_lock);
-out_unlock_buf:
- spin_unlock(&lpfc_cmd->buf_lock);
-out_unlock:
- spin_unlock_irqrestore(&phba->hbalock, flags);
+out_unlock_hba:
+ spin_unlock(&phba->hbalock);
+ spin_unlock_irqrestore(&lpfc_cmd->buf_lock, flags);
out:
lpfc_printf_vlog(vport, KERN_WARNING, LOG_FCP,
"0749 SCSI Layer I/O Abort Request Status x%x ID %d "
--
2.35.1