when I test with command `ib_send_bw -D5 -d mlx5_1` it hangs forever,
the stack I get from `/proc/pid/stack` is
mlx5_ib_post_send_wait+0xce/0x200 [mlx5_ib]
mlx5_ib_update_mr-pas+0x299/0x370 [mlx5_ib]
create_real_mr+0x1a4/0x200 [mlx5_ib]
ib_uverbs_reg_mr+0x17e/0x270 [ib_uverbs]
ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xdd/0x140 [ib_uverbs]
ib_uverbs_run_method+0x229/0x7a0 [ib_uverbs]
ib_uverbs_cmd_verbs.isra.5+0x1a5/0x390 [ib_uverbs]
ib_uverbs_ioctl+0xb8/0x110 [ib_uverbs]
do_vfs_ioctl+0xa4/0x640
ksys_vfs_ioctl+0x70/0x80
do_syscall_64+0x61/0x250
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-------------------------------------------------------------------
OS: openEuler 20.03
Kernel: 4.19.90-2112.8.0.0131.oel
ofed: MLNX_OFED_LINUX-5.7-1.0.2.0
