From f10f582d28220f50099d3f561116256267821429 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Tue, 8 Feb 2022 12:54:48 -0600 Subject: scsi: qedi: Fix ABBA deadlock in qedi_process_tmf_resp() and qedi_process_cmd_cleanup_resp() This fixes a deadlock added with commit b40f3894e39e ("scsi: qedi: Complete TMF works before disconnect") Bug description from Jia-Ju Bai: qedi_process_tmf_resp() spin_lock(&session->back_lock); --> Line 201 (Lock A) spin_lock(&qedi_conn->tmf_work_lock); --> Line 230 (Lock B) qedi_process_cmd_cleanup_resp() spin_lock_bh(&qedi_conn->tmf_work_lock); --> Line 752 (Lock B) spin_lock_bh(&conn->session->back_lock); --> Line 784 (Lock A) When qedi_process_tmf_resp() and qedi_process_cmd_cleanup_resp() are concurrently executed, the deadlock can occur. This patch fixes the deadlock by not holding the tmf_work_lock in qedi_process_cmd_cleanup_resp while holding the back_lock. The tmf_work_lock is only needed while we remove the tmf_work from the work_list. Link: https://lore.kernel.org/r/20220208185448.6206-1-michael.christie@oracle.com Fixes: b40f3894e39e ("scsi: qedi: Complete TMF works before disconnect") Cc: Manish Rangankar Cc: Nilesh Javali Reported-by: TOTE Robot Reported-by: Jia-Ju Bai Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen --- drivers/scsi/qedi/qedi_fw.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'drivers/scsi') diff --git a/drivers/scsi/qedi/qedi_fw.c b/drivers/scsi/qedi/qedi_fw.c index 5916ed7662d5..4eb89aa4a39d 100644 --- a/drivers/scsi/qedi/qedi_fw.c +++ b/drivers/scsi/qedi/qedi_fw.c @@ -771,11 +771,10 @@ static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi, qedi_cmd->list_tmf_work = NULL; } } + spin_unlock_bh(&qedi_conn->tmf_work_lock); - if (!found) { - spin_unlock_bh(&qedi_conn->tmf_work_lock); + if (!found) goto check_cleanup_reqs; - } QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_SCSI_TM, "TMF work, cqe->tid=0x%x, tmf flags=0x%x, cid=0x%x\n", @@ -806,7 +805,6 @@ static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi, qedi_cmd->state = CLEANUP_RECV; unlock: spin_unlock_bh(&conn->session->back_lock); - spin_unlock_bh(&qedi_conn->tmf_work_lock); wake_up_interruptible(&qedi_conn->wait_queue); return; -- cgit