From: Manjunath Patil <manjunath.b.patil@oracle.com>
To: dledford@redhat.com, jgg@ziepe.ca
Cc: manjunath.b.patil@oracle.com, linux-rdma@vger.kernel.org,
linux-kernel@vger.kernel.org, rama.nichanamatlu@oracle.com
Subject: [PATCH RFC] RDMA/cm: add timeout to cm_destroy_id wait
Date: Tue, 27 Feb 2024 12:00:17 -0800 [thread overview]
Message-ID: <20240227200017.308719-1-manjunath.b.patil@oracle.com> (raw)
Add timeout to cm_destroy_id, so that userspace can trigger any data
collection that would help in analyzing the cause of delay in destroying
the cm_id.
New noinline function helps dtrace/ebpf programs to hook on to it.
Existing functionality isn't changed except triggering a probe-able new
function at every timeout interval.
We have seen cases where CM messages stuck with MAD layer (either due to
software bug or faulty HCA), leading to cm_id getting stuck in the
following call stack. This patch helps in resolving such issues faster.
kernel: ... INFO: task XXXX:56778 blocked for more than 120 seconds.
...
Call Trace:
__schedule+0x2bc/0x895
schedule+0x36/0x7c
schedule_timeout+0x1f6/0x31f
? __slab_free+0x19c/0x2ba
wait_for_completion+0x12b/0x18a
? wake_up_q+0x80/0x73
cm_destroy_id+0x345/0x610 [ib_cm]
ib_destroy_cm_id+0x10/0x20 [ib_cm]
rdma_destroy_id+0xa8/0x300 [rdma_cm]
ucma_destroy_id+0x13e/0x190 [rdma_ucm]
ucma_write+0xe0/0x160 [rdma_ucm]
__vfs_write+0x3a/0x16d
vfs_write+0xb2/0x1a1
? syscall_trace_enter+0x1ce/0x2b8
SyS_write+0x5c/0xd3
do_syscall_64+0x79/0x1b9
entry_SYSCALL_64_after_hwframe+0x16d/0x0
Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com>
---
drivers/infiniband/core/cm.c | 38 +++++++++++++++++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index ff58058aeadc..03f7b80efa77 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -34,6 +34,20 @@ MODULE_AUTHOR("Sean Hefty");
MODULE_DESCRIPTION("InfiniBand CM");
MODULE_LICENSE("Dual BSD/GPL");
+static unsigned long cm_destroy_id_wait_timeout_sec = 10;
+
+static struct ctl_table_header *cm_ctl_table_header;
+static struct ctl_table cm_ctl_table[] = {
+ {
+ .procname = "destroy_id_wait_timeout_sec",
+ .data = &cm_destroy_id_wait_timeout_sec,
+ .maxlen = sizeof(cm_destroy_id_wait_timeout_sec),
+ .mode = 0644,
+ .proc_handler = proc_doulongvec_minmax,
+ },
+ { }
+};
+
static const char * const ibcm_rej_reason_strs[] = {
[IB_CM_REJ_NO_QP] = "no QP",
[IB_CM_REJ_NO_EEC] = "no EEC",
@@ -1025,10 +1039,20 @@ static void cm_reset_to_idle(struct cm_id_private *cm_id_priv)
}
}
+static noinline void cm_destroy_id_wait_timeout(struct ib_cm_id *cm_id)
+{
+ struct cm_id_private *cm_id_priv;
+
+ cm_id_priv = container_of(cm_id, struct cm_id_private, id);
+ pr_err("%s: cm_id=%p timed out. state=%d refcnt=%d\n", __func__,
+ cm_id, cm_id->state, refcount_read(&cm_id_priv->refcount));
+}
+
static void cm_destroy_id(struct ib_cm_id *cm_id, int err)
{
struct cm_id_private *cm_id_priv;
struct cm_work *work;
+ int ret;
cm_id_priv = container_of(cm_id, struct cm_id_private, id);
spin_lock_irq(&cm_id_priv->lock);
@@ -1135,7 +1159,14 @@ static void cm_destroy_id(struct ib_cm_id *cm_id, int err)
xa_erase(&cm.local_id_table, cm_local_id(cm_id->local_id));
cm_deref_id(cm_id_priv);
- wait_for_completion(&cm_id_priv->comp);
+ do {
+ ret = wait_for_completion_timeout(&cm_id_priv->comp,
+ msecs_to_jiffies(
+ cm_destroy_id_wait_timeout_sec * 1000));
+ if (!ret) /* timeout happened */
+ cm_destroy_id_wait_timeout(cm_id);
+ } while (!ret);
+
while ((work = cm_dequeue_work(cm_id_priv)) != NULL)
cm_free_work(work);
@@ -4505,6 +4536,10 @@ static int __init ib_cm_init(void)
ret = ib_register_client(&cm_client);
if (ret)
goto error3;
+ cm_ctl_table_header = register_net_sysctl(&init_net,
+ "net/ib_cm", cm_ctl_table);
+ if (!cm_ctl_table_header)
+ pr_warn("ib_cm: couldn't register sysctl path, using default values\n");
return 0;
error3:
@@ -4522,6 +4557,7 @@ static void __exit ib_cm_cleanup(void)
cancel_delayed_work(&timewait_info->work.work);
spin_unlock_irq(&cm.lock);
+ unregister_net_sysctl_table(cm_ctl_table_header);
ib_unregister_client(&cm_client);
destroy_workqueue(cm.wq);
--
2.31.1
next reply other threads:[~2024-02-27 20:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-27 20:00 Manjunath Patil [this message]
2024-03-03 9:58 ` [PATCH RFC] RDMA/cm: add timeout to cm_destroy_id wait Leon Romanovsky
2024-03-05 22:59 ` Manjunath Patil
2024-03-07 9:46 ` Leon Romanovsky
2024-03-07 18:00 ` Manjunath Patil
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