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621e55ff5b
lockdep reports:
WARNING: possible circular locking dependency detected
modprobe/302 is trying to acquire lock:
0000000007c8919c ((wq_completion)ib_cm){+.+.}, at: flush_workqueue+0xdf/0x990
but task is already holding lock:
000000002d3d2ca9 (&device->client_data_rwsem){++++}, at: remove_client_context+0x79/0xd0 [ib_core]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&device->client_data_rwsem){++++}:
down_read+0x3f/0x160
ib_get_net_dev_by_params+0xd5/0x200 [ib_core]
cma_ib_req_handler+0x5f6/0x2090 [rdma_cm]
cm_process_work+0x29/0x110 [ib_cm]
cm_req_handler+0x10f5/0x1c00 [ib_cm]
cm_work_handler+0x54c/0x311d [ib_cm]
process_one_work+0x4aa/0xa30
worker_thread+0x62/0x5b0
kthread+0x1ca/0x1f0
ret_from_fork+0x24/0x30
-> #1 ((work_completion)(&(&work->work)->work)){+.+.}:
process_one_work+0x45f/0xa30
worker_thread+0x62/0x5b0
kthread+0x1ca/0x1f0
ret_from_fork+0x24/0x30
-> #0 ((wq_completion)ib_cm){+.+.}:
lock_acquire+0xc8/0x1d0
flush_workqueue+0x102/0x990
cm_remove_one+0x30e/0x3c0 [ib_cm]
remove_client_context+0x94/0xd0 [ib_core]
disable_device+0x10a/0x1f0 [ib_core]
__ib_unregister_device+0x5a/0xe0 [ib_core]
ib_unregister_device+0x21/0x30 [ib_core]
mlx5_ib_stage_ib_reg_cleanup+0x9/0x10 [mlx5_ib]
__mlx5_ib_remove+0x3d/0x70 [mlx5_ib]
mlx5_ib_remove+0x12e/0x140 [mlx5_ib]
mlx5_remove_device+0x144/0x150 [mlx5_core]
mlx5_unregister_interface+0x3f/0xf0 [mlx5_core]
mlx5_ib_cleanup+0x10/0x3a [mlx5_ib]
__x64_sys_delete_module+0x227/0x350
do_syscall_64+0xc3/0x6a4
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Which is due to the read side of the client_data_rwsem being obtained
recursively through a work queue flush during cm client removal.
The lock is being held across the remove in remove_client_context() so
that the function is a fence, once it returns the client is removed. This
is required so that the two callers do not proceed with destruction until
the client completes removal.
Instead of using client_data_rwsem use the existing device unregistration
refcount and add a similar client unregistration (client->uses) refcount.
This will fence the two unregistration paths without holding any locks.
Cc: <stable@vger.kernel.org>
Fixes:
|
||
|---|---|---|
| .. | ||
| addr.c | ||
| agent.c | ||
| agent.h | ||
| cache.c | ||
| cgroup.c | ||
| cm_msgs.h | ||
| cm.c | ||
| cma_configfs.c | ||
| cma_priv.h | ||
| cma.c | ||
| core_priv.h | ||
| counters.c | ||
| cq.c | ||
| device.c | ||
| fmr_pool.c | ||
| iwcm.c | ||
| iwcm.h | ||
| iwpm_msg.c | ||
| iwpm_util.c | ||
| iwpm_util.h | ||
| mad_priv.h | ||
| mad_rmpp.c | ||
| mad_rmpp.h | ||
| mad.c | ||
| Makefile | ||
| mr_pool.c | ||
| multicast.c | ||
| netlink.c | ||
| nldev.c | ||
| opa_smi.h | ||
| packer.c | ||
| rdma_core.c | ||
| rdma_core.h | ||
| restrack.c | ||
| restrack.h | ||
| roce_gid_mgmt.c | ||
| rw.c | ||
| sa_query.c | ||
| sa.h | ||
| security.c | ||
| smi.c | ||
| smi.h | ||
| sysfs.c | ||
| ucma.c | ||
| ud_header.c | ||
| umem_odp.c | ||
| umem.c | ||
| user_mad.c | ||
| uverbs_cmd.c | ||
| uverbs_ioctl.c | ||
| uverbs_main.c | ||
| uverbs_marshall.c | ||
| uverbs_std_types_counters.c | ||
| uverbs_std_types_cq.c | ||
| uverbs_std_types_device.c | ||
| uverbs_std_types_dm.c | ||
| uverbs_std_types_flow_action.c | ||
| uverbs_std_types_mr.c | ||
| uverbs_std_types.c | ||
| uverbs_uapi.c | ||
| uverbs.h | ||
| verbs.c | ||