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| author | Zhu Yanjun <yanjunz@mellanox.com> | 2020-02-12 09:26:33 +0200 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@mellanox.com> | 2020-02-13 10:51:09 -0400 |
| commit | 8ac0e6641c7ca14833a2a8c6f13d8e0a435e535c (patch) | |
| tree | 00de5588fd13d073c0afd968e4c6ece95ae2d494 | |
| parent | 9b6d3bbc1335404b331f4f11dc896066bdf1c752 (diff) | |
| download | lwn-8ac0e6641c7ca14833a2a8c6f13d8e0a435e535c.tar.gz lwn-8ac0e6641c7ca14833a2a8c6f13d8e0a435e535c.zip | |
RDMA/rxe: Fix soft lockup problem due to using tasklets in softirq
When run stress tests with RXE, the following Call Traces often occur
watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [swapper/2:0]
...
Call Trace:
<IRQ>
create_object+0x3f/0x3b0
kmem_cache_alloc_node_trace+0x129/0x2d0
__kmalloc_reserve.isra.52+0x2e/0x80
__alloc_skb+0x83/0x270
rxe_init_packet+0x99/0x150 [rdma_rxe]
rxe_requester+0x34e/0x11a0 [rdma_rxe]
rxe_do_task+0x85/0xf0 [rdma_rxe]
tasklet_action_common.isra.21+0xeb/0x100
__do_softirq+0xd0/0x298
irq_exit+0xc5/0xd0
smp_apic_timer_interrupt+0x68/0x120
apic_timer_interrupt+0xf/0x20
</IRQ>
...
The root cause is that tasklet is actually a softirq. In a tasklet
handler, another softirq handler is triggered. Usually these softirq
handlers run on the same cpu core. So this will cause "soft lockup Bug".
Fixes: 8700e3e7c485 ("Soft RoCE driver")
Link: https://lore.kernel.org/r/20200212072635.682689-8-leon@kernel.org
Signed-off-by: Zhu Yanjun <yanjunz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
| -rw-r--r-- | drivers/infiniband/sw/rxe/rxe_comp.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c index 116cafc9afcf..4bc88708b355 100644 --- a/drivers/infiniband/sw/rxe/rxe_comp.c +++ b/drivers/infiniband/sw/rxe/rxe_comp.c @@ -329,7 +329,7 @@ static inline enum comp_state check_ack(struct rxe_qp *qp, qp->comp.psn = pkt->psn; if (qp->req.wait_psn) { qp->req.wait_psn = 0; - rxe_run_task(&qp->req.task, 1); + rxe_run_task(&qp->req.task, 0); } } return COMPST_ERROR_RETRY; @@ -463,7 +463,7 @@ static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe) */ if (qp->req.wait_fence) { qp->req.wait_fence = 0; - rxe_run_task(&qp->req.task, 1); + rxe_run_task(&qp->req.task, 0); } } @@ -479,7 +479,7 @@ static inline enum comp_state complete_ack(struct rxe_qp *qp, if (qp->req.need_rd_atomic) { qp->comp.timeout_retry = 0; qp->req.need_rd_atomic = 0; - rxe_run_task(&qp->req.task, 1); + rxe_run_task(&qp->req.task, 0); } } @@ -725,7 +725,7 @@ int rxe_completer(void *arg) RXE_CNT_COMP_RETRY); qp->req.need_retry = 1; qp->comp.started_retry = 1; - rxe_run_task(&qp->req.task, 1); + rxe_run_task(&qp->req.task, 0); } if (pkt) { |