Hi, Recently I was running into a hung task on kernel client. After investigating the environment, I think there might be a deadlock caused by calling iput inside OSD dispatch(ceph-msgr) thread My kernel cpeh client version is 5.15 The call stack for the kernel ceph-msgr thread is: [<0>] wait_on_page_bit_common+0x106/0x300 [<0>] truncate_inode_pages_range+0x381/0x6a0 [<0>] ceph_evict_inode+0x4a/0x200 [ceph] [<0>] evict+0xc6/0x190 [<0>] ceph_put_wrbuffer_cap_refs+0xdf/0x1d0 [ceph] [<0>] writepages_finish+0x2c4/0x440 [ceph] [<0>] handle_reply+0x5be/0x6d0 [libceph] [<0>] dispatch+0x49/0xa60 [libceph] [<0>] ceph_con_workfn+0x10fa/0x24b0 [libceph] [<0>] worker_run_work+0xb8/0xd0 [<0>] process_one_work+0x1d3/0x3c0 [<0>] worker_thread+0x4d/0x3e0 [<0>] kthread+0x12d/0x150 [<0>] ret_from_fork+0x1f/0x30 And the following messages are from osdc in ceph debugfs 2774296 osd30 4.1ea6f009 4.9 [30,14]/30 [30,14]/30 e18281 200006dabea.00000003 0x40002c 92 write ... 2774578 osd30 4.1ea6f009 4.9 [30,14]/30 [30,14]/30 e18281 200006dabea.00000003 0x400014 1 read 2774579 osd30 4.1ea6f009 4.9 [30,14]/30 [30,14]/30 e18281 200006dabea.00000003 0x400014 1 read 2774580 osd30 4.1ea6f009 4.9 [30,14]/30 [30,14]/30 e18281 200006dabea.00000003 0x400014 1 read 2774581 osd30 4.1ea6f009 4.9 [30,14]/30 [30,14]/30 e18281 200006dabea.00000003 0x400014 1 read 2774582 osd30 4.1ea6f009 4.9 [30,14]/30 [30,14]/30 e18281 200006dabea.00000003 0x400014 1 read 2774583 osd30 4.1ea6f009 4.9 [30,14]/30 [30,14]/30 e18281 200006dabea.00000003 0x400014 1 read 2774584 osd30 4.1ea6f009 4.9 [30,14]/30 [30,14]/30 e18281 200006dabea.00000003 0x400014 1 read ... We can see that kernel client has sent both write and multiple read requests on object 200006dabea.00000003. The iput_final waits for truncate_inode_pages_range to finish which in turn waits for page bit.
