diff options
| author | Selvin Xavier <selvin.xavier@broadcom.com> | 2018-10-08 03:27:53 -0700 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@mellanox.com> | 2018-10-16 00:03:50 -0600 |
| commit | d455f29f6d76a5f94881ca1289aaa1e90617ff5d (patch) | |
| tree | d8132782f64f33522885f712568800f72d98b27d /drivers/infiniband/hw/bnxt_re/qplib_rcfw.c | |
| parent | 5a23e0b1dd51fe0efae666b03fdb15e1301f437a (diff) | |
RDMA/bnxt_re: Fix recursive lock warning in debug kernel
Fix possible recursive lock warning. Its a false warning as the locks are
part of two differnt HW Queue data structure - cmdq and creq. Debug kernel
is throwing the following warning and stack trace.
[ 783.914967] ============================================
[ 783.914970] WARNING: possible recursive locking detected
[ 783.914973] 4.19.0-rc2+ #33 Not tainted
[ 783.914976] --------------------------------------------
[ 783.914979] swapper/2/0 is trying to acquire lock:
[ 783.914982] 000000002aa3949d (&(&hwq->lock)->rlock){..-.}, at: bnxt_qplib_service_creq+0x232/0x350 [bnxt_re]
[ 783.914999]
but task is already holding lock:
[ 783.915002] 00000000be73920d (&(&hwq->lock)->rlock){..-.}, at: bnxt_qplib_service_creq+0x2a/0x350 [bnxt_re]
[ 783.915013]
other info that might help us debug this:
[ 783.915016] Possible unsafe locking scenario:
[ 783.915019] CPU0
[ 783.915021] ----
[ 783.915034] lock(&(&hwq->lock)->rlock);
[ 783.915035] lock(&(&hwq->lock)->rlock);
[ 783.915037]
*** DEADLOCK ***
[ 783.915038] May be due to missing lock nesting notation
[ 783.915039] 1 lock held by swapper/2/0:
[ 783.915040] #0: 00000000be73920d (&(&hwq->lock)->rlock){..-.}, at: bnxt_qplib_service_creq+0x2a/0x350 [bnxt_re]
[ 783.915044]
stack backtrace:
[ 783.915046] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.19.0-rc2+ #33
[ 783.915047] Hardware name: Dell Inc. PowerEdge R730/0599V5, BIOS 1.0.4 08/28/2014
[ 783.915048] Call Trace:
[ 783.915049] <IRQ>
[ 783.915054] dump_stack+0x90/0xe3
[ 783.915058] __lock_acquire+0x106c/0x1080
[ 783.915061] ? sched_clock+0x5/0x10
[ 783.915063] lock_acquire+0xbd/0x1a0
[ 783.915065] ? bnxt_qplib_service_creq+0x232/0x350 [bnxt_re]
[ 783.915069] _raw_spin_lock_irqsave+0x4a/0x90
[ 783.915071] ? bnxt_qplib_service_creq+0x232/0x350 [bnxt_re]
[ 783.915073] bnxt_qplib_service_creq+0x232/0x350 [bnxt_re]
[ 783.915078] tasklet_action_common.isra.17+0x197/0x1b0
[ 783.915081] __do_softirq+0xcb/0x3a6
[ 783.915084] irq_exit+0xe9/0x100
[ 783.915085] do_IRQ+0x6a/0x120
[ 783.915087] common_interrupt+0xf/0xf
[ 783.915088] </IRQ>
Use nested notation for the spin_lock to avoid this warning.
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'drivers/infiniband/hw/bnxt_re/qplib_rcfw.c')
| -rw-r--r-- | drivers/infiniband/hw/bnxt_re/qplib_rcfw.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c index 14105004d258..0c6a3acef2db 100644 --- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c +++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c @@ -311,8 +311,17 @@ static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw, rcfw->aeq_handler(rcfw, qp_event, qp); break; default: - /* Command Response */ - spin_lock_irqsave(&cmdq->lock, flags); + /* + * Command Response + * cmdq->lock needs to be acquired to synchronie + * the command send and completion reaping. This function + * is always called with creq->lock held. Using + * the nested variant of spin_lock. + * + */ + + spin_lock_irqsave_nested(&cmdq->lock, flags, + SINGLE_DEPTH_NESTING); cookie = le16_to_cpu(qp_event->cookie); mcookie = qp_event->cookie; blocked = cookie & RCFW_CMD_IS_BLOCKING; |