Manjunath Patil baf8a6d2cd RDMA/cm: add timeout to cm_destroy_id wait
[ Upstream commit 96d9cbe2f2ff7abde021bac75eafaceabe9a51fa ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-13 13:01:45 +02:00
2021-10-18 20:22:03 -10:00
2024-04-10 16:19:24 +02:00
2024-04-10 16:19:44 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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