• Manjunath Patil's avatar
    RDMA/cm: add timeout to cm_destroy_id wait · 96d9cbe2
    Manjunath Patil authored
    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: default avatarManjunath Patil <manjunath.b.patil@oracle.com>
    Link: https://lore.kernel.org/r/20240309063323.458102-1-manjunath.b.patil@oracle.comSigned-off-by: default avatarLeon Romanovsky <leon@kernel.org>
    96d9cbe2
cm.c 130 KB