On 3/8/24 6:18 AM, Jason Gunthorpe wrote:
On Thu, Mar 07, 2024 at 04:55:53PM -0800, Manjunath Patil wrote:
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
Orabug: 36280065
Signed-off-by: Manjunath Patil <manjunath.b.patil@xxxxxxxxxx>
---
drivers/infiniband/core/cm.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index ff58058aeadc..00a16b08c7e2 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -34,6 +34,7 @@ MODULE_AUTHOR("Sean Hefty");
MODULE_DESCRIPTION("InfiniBand CM");
MODULE_LICENSE("Dual BSD/GPL");
+static unsigned long cm_destroy_id_wait_timeout_sec = 10;
Don't need this to be a variable, just make it a #define
sure. I will send v3 with this change.
static const char * const ibcm_rej_reason_strs[] = {
[IB_CM_REJ_NO_QP] = "no QP",
[IB_CM_REJ_NO_EEC] = "no EEC",
@@ -1025,10 +1026,20 @@ 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));
+}
WARN_ON? Is the backtrace valuable?
No. I would prefer just pr_err to avoid noise if there are multiple cm_ids are stuck due to any lower layer issue.
Thank you for your feedback.
-Manjunath
Jason
