From: Mike Christie michael.christie@oracle.com
commit f10f582d28220f50099d3f561116256267821429 upstream.
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 mrangankar@marvell.com Cc: Nilesh Javali njavali@marvell.com Reported-by: TOTE Robot oslab@tsinghua.edu.cn Reported-by: Jia-Ju Bai baijiaju1990@gmail.com Signed-off-by: Mike Christie michael.christie@oracle.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/scsi/qedi/qedi_fw.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
--- a/drivers/scsi/qedi/qedi_fw.c +++ b/drivers/scsi/qedi/qedi_fw.c @@ -771,11 +771,10 @@ static void qedi_process_cmd_cleanup_res 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_res 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;