- When a iSER session is released, ib_isert module is taking a mutex lock and
releasing all pending connections. As part of this, ib_isert is destroying
rdma cm_id. To destroy cm_id, rdma_cm module is sending CM events to CMA
handler of ib_isert. This handler is taking same mutex lock. Hence it leads
to deadlock between ib_isert & rdma_cm modules.
- For fix, created local list of pending connections and release the connection
outside of mutex lock.
Calltrace:
---------
[ 1229.791410] INFO: task kworker/10:1:642 blocked for more than 120 seconds.
[ 1229.791416] Tainted: G OE --------- - - 4.18.0-372.9.1.el8.x86_64 #1
[ 1229.791418] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1229.791419] task:kworker/10:1 state:D stack: 0 pid: 642 ppid: 2 flags:0x80004000
[ 1229.791424] Workqueue: ib_cm cm_work_handler [ib_cm]
[ 1229.791436] Call Trace:
[ 1229.791438] __schedule+0x2d1/0x830
[ 1229.791445] ? select_idle_sibling+0x23/0x6f0
[ 1229.791449] schedule+0x35/0xa0
[ 1229.791451] schedule_preempt_disabled+0xa/0x10
[ 1229.791453] __mutex_lock.isra.7+0x310/0x420
[ 1229.791456] ? select_task_rq_fair+0x351/0x990
[ 1229.791459] isert_cma_handler+0x224/0x330 [ib_isert]
[ 1229.791463] ? ttwu_queue_wakelist+0x159/0x170
[ 1229.791466] cma_cm_event_handler+0x25/0xd0 [rdma_cm]
[ 1229.791474] cma_ib_handler+0xa7/0x2e0 [rdma_cm]
[ 1229.791478] cm_process_work+0x22/0xf0 [ib_cm]
[ 1229.791483] cm_work_handler+0xf4/0xf30 [ib_cm]
[ 1229.791487] ? move_linked_works+0x6e/0xa0
[ 1229.791490] process_one_work+0x1a7/0x360
[ 1229.791491] ? create_worker+0x1a0/0x1a0
[ 1229.791493] worker_thread+0x30/0x390
[ 1229.791494] ? create_worker+0x1a0/0x1a0
[ 1229.791495] kthread+0x10a/0x120
[ 1229.791497] ? set_kthread_struct+0x40/0x40
[ 1229.791499] ret_from_fork+0x1f/0x40
[ 1229.791739] INFO: task targetcli:28666 blocked for more than 120 seconds.
[ 1229.791740] Tainted: G OE --------- - - 4.18.0-372.9.1.el8.x86_64 #1
[ 1229.791741] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1229.791742] task:targetcli state:D stack: 0 pid:28666 ppid: 5510 flags:0x00004080
[ 1229.791743] Call Trace:
[ 1229.791744] __schedule+0x2d1/0x830
[ 1229.791746] schedule+0x35/0xa0
[ 1229.791748] schedule_preempt_disabled+0xa/0x10
[ 1229.791749] __mutex_lock.isra.7+0x310/0x420
[ 1229.791751] rdma_destroy_id+0x15/0x20 [rdma_cm]
[ 1229.791755] isert_connect_release+0x115/0x130 [ib_isert]
[ 1229.791757] isert_free_np+0x87/0x140 [ib_isert]
[ 1229.791761] iscsit_del_np+0x74/0x120 [iscsi_target_mod]
[ 1229.791776] lio_target_np_driver_store+0xe9/0x140 [iscsi_target_mod]
[ 1229.791784] configfs_write_file+0xb2/0x110
[ 1229.791788] vfs_write+0xa5/0x1a0
[ 1229.791792] ksys_write+0x4f/0xb0
[ 1229.791794] do_syscall_64+0x5b/0x1a0
[ 1229.791798] entry_SYSCALL_64_after_hwframe+0x65/0xca
Fixes: bd3792205aae ("iser-target: Fix pending connections handling in target stack shutdown sequnce")
Signed-off-by: Selvin Xavier <selvin.xavier@xxxxxxxxxxxx>
Signed-off-by: Saravanan Vajravel <saravanan.vajravel@xxxxxxxxxxxx>
---
drivers/infiniband/ulp/isert/ib_isert.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index f290cd49698e..b4809d237250 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -2431,6 +2431,7 @@ isert_free_np(struct iscsi_np *np)
{
struct isert_np *isert_np = np->np_context;
struct isert_conn *isert_conn, *n;
+ LIST_HEAD(drop_conn_list);
if (isert_np->cm_id)
rdma_destroy_id(isert_np->cm_id);
@@ -2450,7 +2451,7 @@ isert_free_np(struct iscsi_np *np)
node) {
isert_info("cleaning isert_conn %p state (%d)\n",
isert_conn, isert_conn->state);
- isert_connect_release(isert_conn);
+ list_move_tail(&isert_conn->node, &drop_conn_list);
}
}
@@ -2461,11 +2462,16 @@ isert_free_np(struct iscsi_np *np)
node) {
isert_info("cleaning isert_conn %p state (%d)\n",
isert_conn, isert_conn->state);
- isert_connect_release(isert_conn);
+ list_move_tail(&isert_conn->node, &drop_conn_list);
}
}
mutex_unlock(&isert_np->mutex);
+ list_for_each_entry_safe(isert_conn, n, &drop_conn_list, node) {
+ list_del_init(&isert_conn->node);
+ isert_connect_release(isert_conn);
+ }
+
np->np_context = NULL;
kfree(isert_np);
}
--
2.31.1
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