From: Zhu Yanjun <yanjunz@xxxxxxxxxxxx>
commit 8ac0e6641c7ca14833a2a8c6f13d8e0a435e535c upstream.
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@xxxxxxxxxx
Signed-off-by: Zhu Yanjun <yanjunz@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_comp.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- 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(
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 *q
*/
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_a
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) {
