RDMA/cm: add timeout to cm_destroy_id wait
authorManjunath Patil <manjunath.b.patil@oracle.com>
Sat, 9 Mar 2024 06:33:23 +0000 (22:33 -0800)
committerLeon Romanovsky <leon@kernel.org>
Sun, 10 Mar 2024 11:17:54 +0000 (13:17 +0200)
commit96d9cbe2f2ff7abde021bac75eafaceabe9a51fa
tree06f5ce1c681da5d07cdbd2f0e22dbdb8b5c4067d
parent2d5c00815778ec4f4e0a84e405e3e157b7815db1
RDMA/cm: add timeout to cm_destroy_id wait

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>
Link: https://lore.kernel.org/r/20240309063323.458102-1-manjunath.b.patil@oracle.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
drivers/infiniband/core/cm.c