I'm reporting a bug in linux-4.19.19: "INFO: task hung in reiserfs_sync_fs" (no reproducer) ========================================= INFO: task kworker/0:1:13513 blocked for more than 120 seconds. Not tainted 4.19.19 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:1 D27376 13513 2 0x80000000 Workqueue: events_long flush_old_commits Call Trace: context_switch kernel/sched/core.c:2824 [inline] __schedule+0x809/0x2160 kernel/sched/core.c:3472 schedule+0x88/0x1c0 kernel/sched/core.c:3516 schedule_preempt_disabled+0x18/0x30 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x50c/0x1330 kernel/locking/mutex.c:1072 mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:1087 reiserfs_write_lock+0x87/0x140 fs/reiserfs/lock.c:27 reiserfs_sync_fs+0x77/0xf0 fs/reiserfs/super.c:76 flush_old_commits+0x16d/0x210 fs/reiserfs/super.c:111 process_one_work+0x9f7/0x1800 kernel/workqueue.c:2153 worker_thread+0x8f/0xd20 kernel/workqueue.c:2296 kthread+0x3a3/0x470 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 INFO: task syz-executor1:2786 blocked for more than 120 seconds. Not tainted 4.19.19 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D27200 2786 6598 0x00000004 Call Trace: context_switch kernel/sched/core.c:2824 [inline] __schedule+0x809/0x2160 kernel/sched/core.c:3472 schedule+0x88/0x1c0 kernel/sched/core.c:3516 schedule_preempt_disabled+0x18/0x30 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x50c/0x1330 kernel/locking/mutex.c:1072 mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:1087 reiserfs_write_lock+0x87/0x140 fs/reiserfs/lock.c:27 reiserfs_get_block+0x22c/0x45d0 fs/reiserfs/inode.c:688 do_mpage_readpage+0x586/0x23b0 fs/mpage.c:231 mpage_readpages+0x412/0x5a0 fs/mpage.c:404 reiserfs_readpages+0x31/0x40 fs/reiserfs/inode.c:1167 read_pages+0x117/0x5a0 mm/readahead.c:123 __do_page_cache_readahead+0x503/0x660 mm/readahead.c:211 ra_submit mm/internal.h:66 [inline] ondemand_readahead+0x465/0xd90 mm/readahead.c:493 page_cache_sync_readahead+0xcd/0x120 mm/readahead.c:528 generic_file_buffered_read mm/filemap.c:2092 [inline] generic_file_read_iter+0x162b/0x2520 mm/filemap.c:2362 call_read_iter include/linux/fs.h:1805 [inline] new_sync_read fs/read_write.c:406 [inline] __vfs_read+0x535/0x6d0 fs/read_write.c:418 vfs_read+0x139/0x370 fs/read_write.c:452 ksys_read+0xde/0x1c0 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x7e/0xc0 fs/read_write.c:586 do_syscall_64+0xc4/0x510 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4497b9 Code: 72 20 6c 69 6e 65 20 73 75 63 63 65 73 73 66 75 6c 6c 79 20 70 72 6f 63 65 73 73 65 64 0a 00 50 72 6f 63 65 73 73 69 6e 67 20 <6e> 65 78 74 20 61 63 74 69 6f 6e 0a 00 54 52 55 45 00 46 41 4c 53 RSP: 002b:00007f632463ac68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f632463b6cc RCX: 00000000004497b9 RDX: 000000000000008c RSI: 0000000020000100 RDI: 0000000000000014 RBP: 000000000071bf58 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000008298 R14: 00000000006f1338 R15: 00007f632463b700 INFO: task syz-executor4:2784 blocked for more than 120 seconds. Not tainted 4.19.19 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D27712 2784 6606 0x00000004 Call Trace: context_switch kernel/sched/core.c:2824 [inline] __schedule+0x809/0x2160 kernel/sched/core.c:3472 schedule+0x88/0x1c0 kernel/sched/core.c:3516 io_schedule+0x21/0x80 kernel/sched/core.c:5139 wait_on_page_bit_common mm/filemap.c:1100 [inline] __lock_page+0x2d2/0x3b0 mm/filemap.c:1273 lock_page include/linux/pagemap.h:483 [inline] pagecache_get_page+0x4b3/0x870 mm/filemap.c:1554 find_or_create_page include/linux/pagemap.h:322 [inline] grab_cache_page include/linux/pagemap.h:388 [inline] grab_tail_page fs/reiserfs/inode.c:2206 [inline] reiserfs_truncate_file+0x3fa/0xe60 fs/reiserfs/inode.c:2274 reiserfs_vfs_truncate_file+0x37/0x50 fs/reiserfs/file.c:139 reiserfs_direct_IO+0x205/0x270 fs/reiserfs/inode.c:3275 generic_file_direct_write+0x20d/0x4a0 mm/filemap.c:3042 __generic_file_write_iter+0x244/0x6c0 mm/filemap.c:3221 generic_file_write_iter+0x31e/0x6e0 mm/filemap.c:3292 call_write_iter include/linux/fs.h:1811 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x538/0x6e0 fs/read_write.c:487 vfs_write+0x1b3/0x520 fs/read_write.c:549 ksys_write+0xde/0x1c0 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x7e/0xc0 fs/read_write.c:607 do_syscall_64+0xc4/0x510 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4497b9 Code: 72 20 6c 69 6e 65 20 73 75 63 63 65 73 73 66 75 6c 6c 79 20 70 72 6f 63 65 73 73 65 64 0a 00 50 72 6f 63 65 73 73 69 6e 67 20 <6e> 65 78 74 20 61 63 74 69 6f 6e 0a 00 54 52 55 45 00 46 41 4c 53 RSP: 002b:00007f9063a4fc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f9063a506cc RCX: 00000000004497b9 RDX: 000000000000001e RSI: 0000000020002400 RDI: 0000000000000014 RBP: 000000000071bf58 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000bda8 R14: 00000000006f4e48 R15: 00007f9063a50700 Showing all locks held in the system: 1 lock held by khungtaskd/1847: #0: 000000004cfccd54 (rcu_read_lock){....}, at: debug_show_all_locks+0x5c/0x350 kernel/locking/lockdep.c:4433 1 lock held by rsyslogd/6361: #0: 0000000056b818c6 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xd6/0x100 fs/file.c:766 2 locks held by getty/6453: #0: 00000000903a8664 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000697dee47 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x20a/0x19e0 drivers/tty/n_tty.c:2154 2 locks held by getty/6454: #0: 0000000010b79e14 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000f9107645 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x20a/0x19e0 drivers/tty/n_tty.c:2154 2 locks held by getty/6455: #0: 0000000080e8b82e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000217d9bd2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x20a/0x19e0 drivers/tty/n_tty.c:2154 2 locks held by getty/6456: #0: 00000000a53d12ec (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:363 #1: 0000000093e4d8c1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x20a/0x19e0 drivers/tty/n_tty.c:2154 2 locks held by getty/6457: #0: 00000000a1e7395b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:363 #1: 000000001a2357cd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x20a/0x19e0 drivers/tty/n_tty.c:2154 2 locks held by getty/6458: #0: 0000000048073f4a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:363 #1: 000000005b6e2c95 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x20a/0x19e0 drivers/tty/n_tty.c:2154 2 locks held by getty/6459: #0: 00000000be696ff9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:363 #1: 00000000947c2146 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x20a/0x19e0 drivers/tty/n_tty.c:2154 4 locks held by kworker/0:1/13513: #0: 00000000c7a968a8 ((wq_completion)"events_long"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000c7a968a8 ((wq_completion)"events_long"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000c7a968a8 ((wq_completion)"events_long"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000c7a968a8 ((wq_completion)"events_long"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000c7a968a8 ((wq_completion)"events_long"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000c7a968a8 ((wq_completion)"events_long"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000c7a968a8 ((wq_completion)"events_long"){+.+.}, at: process_one_work+0x90a/0x1800 kernel/workqueue.c:2124 #1: 0000000007d37b78 ((work_completion)(&(&sbi->old_work)->work)){+.+.}, at: process_one_work+0x941/0x1800 kernel/workqueue.c:2128 #2: 00000000a67b6505 (&type->s_umount_key#41){.+.+}, at: flush_old_commits+0x8a/0x210 fs/reiserfs/super.c:97 #3: 000000005f1d7713 (&sbi->lock){+.+.}, at: reiserfs_write_lock+0x87/0x140 fs/reiserfs/lock.c:27 2 locks held by syz-executor1/2786: #0: 00000000be156f84 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xd6/0x100 fs/file.c:766 #1: 000000005f1d7713 (&sbi->lock){+.+.}, at: reiserfs_write_lock+0x87/0x140 fs/reiserfs/lock.c:27 5 locks held by syz-executor4/2784: #0: 000000005b4c5c72 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xd6/0x100 fs/file.c:766 #1: 0000000054b50e8f (sb_writers#12){.+.+}, at: file_start_write include/linux/fs.h:2764 [inline] #1: 0000000054b50e8f (sb_writers#12){.+.+}, at: vfs_write+0x443/0x520 fs/read_write.c:548 #2: 0000000063973fb8 (&sb->s_type->i_mutex_key#17){+.+.}, at: inode_lock include/linux/fs.h:738 [inline] #2: 0000000063973fb8 (&sb->s_type->i_mutex_key#17){+.+.}, at: generic_file_write_iter+0x9f/0x6e0 mm/filemap.c:3289 #3: 00000000e8bc4bf8 (&ei->tailpack){+.+.}, at: reiserfs_vfs_truncate_file+0x2a/0x50 fs/reiserfs/file.c:138 #4: 000000005f1d7713 (&sbi->lock){+.+.}, at: reiserfs_write_lock+0x87/0x140 fs/reiserfs/lock.c:27 ========================================= Thanks, Kyungtae