[PATCH AUTOSEL 4.19 055/123] RDMA/bnxt_re: Fix system hang when registration with L2 driver fails

Sasha Levin
2018-12-05T09:39:12Z

From: Selvin Xavier <selvin.xavier@broadcom.com>

[ Upstream commit 3c4b1419c33c2417836a63f8126834ee36968321 ]

Driver doesn't release rtnl lock if registration with
L2 driver (bnxt_re_register_netdev) fais and this causes
hang while requesting for the next lock.

[ 371.635416] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 371.635417] kworker/u48:1 D 0 634 2 0x80000000
[ 371.635423] Workqueue: bnxt_re bnxt_re_task [bnxt_re]
[ 371.635424] Call Trace:
[ 371.635426] ? __schedule+0x36b/0xbd0
[ 371.635429] schedule+0x39/0x90
[ 371.635430] schedule_preempt_disabled+0x11/0x20
[ 371.635431] __mutex_lock+0x45b/0x9c0
[ 371.635433] ? __mutex_lock+0x16d/0x9c0
[ 371.635435] ? bnxt_re_ib_reg+0x2b/0xb30 [bnxt_re]
[ 371.635438] ? wake_up_klogd+0x37/0x40
[ 371.635442] bnxt_re_ib_reg+0x2b/0xb30 [bnxt_re]
[ 371.635447] bnxt_re_task+0xfd/0x180 [bnxt_re]
[ 371.635449] process_one_work+0x216/0x5b0
[ 371.635450] ? process_one_work+0x189/0x5b0
[ 371.635453] worker_thread+0x4e/0x3d0
[ 371.635455] kthread+0x10e/0x140
[ 371.635456] ? process_one_work+0x5b0/0x5b0
[ 371.635458] ? kthread_stop+0x220/0x220
[ 371.635460] ret_from_fork+0x3a/0x50
[ 371.635477] INFO: task NetworkManager:1228 blocked for more than 120 seconds.
[ 371.635478] Tainted: G B OE 4.20.0-rc1+ #42
[ 371.635479] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

Release the rtnl_lock correctly in the failure path.

Fixes: de5c95d0f518 ("RDMA/bnxt_re: Fix system crash during RDMA resource initialization")
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/hw/bnxt_re/main.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/hw/bnxt_re/main.c b/drivers/infiniband/hw/bnxt_re/main.c
index 85cd1a3593d6..bb3f16273938 100644
--- a/drivers/infiniband/hw/bnxt_re/main.c
+++ b/drivers/infiniband/hw/bnxt_re/main.c
@@ -1252,6 +1252,7 @@ static int bnxt_re_ib_reg(struct bnxt_re_dev *rdev)
/* Registered a new RoCE device instance to netdev */
rc = bnxt_re_register_netdev(rdev);
if (rc) {
+ rtnl_unlock();
pr_err("Failed to register with netedev: %#x\n", rc);
return -EINVAL;
}
--
2.17.1