syzbot


INFO: task hung in __writeback_single_inode

Status: auto-closed as invalid on 2020/02/21 11:34
Reported-by: syzbot+dc66bde1623d1442a09d@syzkaller.appspotmail.com
First crash: 1635d, last: 1635d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: task hung in __writeback_single_inode xfs 1 452d 452d 0/1 upstream: reported on 2023/01/18 22:36

Sample crash report:
INFO: task syz-executor.2:25274 blocked for more than 140 seconds.
      Not tainted 4.9.194+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D26040 25274  26354 0x00000004
 0000000000000083 ffff880154b24740 0000000000000000 ffff8801db721000
 ffff8801d66ec740 ffff8801db721018 ffff88016c28f040 ffffffff8281af8e
 ffffffff81bcd85d ffff880154b24740 00ff880154b24740 ffff8801db7218f0
Call Trace:
 [<000000007057ec78>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<000000007f238dc4>] schedule_timeout+0x766/0xe50 kernel/time/timer.c:1771
 [<000000002bd8e79e>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5171
 [<00000000cdd79ba5>] io_schedule include/linux/sched.h:432 [inline]
 [<00000000cdd79ba5>] wait_on_page_bit_common mm/filemap.c:910 [inline]
 [<00000000cdd79ba5>] wait_on_page_bit+0x34c/0x660 mm/filemap.c:949
 [<000000006af34885>] wait_on_page_writeback include/linux/pagemap.h:534 [inline]
 [<000000006af34885>] __filemap_fdatawait_range+0x185/0x240 mm/filemap.c:453
 [<00000000654ba29d>] filemap_fdatawait_range+0x26/0x50 mm/filemap.c:483
 [<000000002dbd9e67>] filemap_fdatawait+0x66/0x90 mm/filemap.c:533
 [<00000000e2f9e04a>] __writeback_single_inode+0x748/0x1040 fs/fs-writeback.c:1374
 [<000000007b472d09>] writeback_single_inode+0x256/0x450 fs/fs-writeback.c:1477
 [<00000000b09dae8d>] sync_inode fs/fs-writeback.c:2505 [inline]
 [<00000000b09dae8d>] sync_inode_metadata+0xc3/0x100 fs/fs-writeback.c:2525
 [<00000000d2481be8>] __generic_file_fsync+0x14c/0x1c0 fs/libfs.c:985
 [<00000000e8bb065c>] ext4_sync_file+0x656/0x1090 fs/ext4/fsync.c:116
 [<000000002c1f75e7>] vfs_fsync_range+0x111/0x260 fs/sync.c:195
 [<00000000f4505509>] generic_write_sync include/linux/fs.h:2613 [inline]
 [<00000000f4505509>] ext4_file_write_iter+0x8b5/0xcd0 fs/ext4/file.c:176
 [<00000000de52c963>] vfs_iter_write+0x2e2/0x580 fs/read_write.c:390
 [<0000000092c5e6cb>] iter_file_splice_write+0x5a9/0xb10 fs/splice.c:768
 [<00000000536a2c3f>] do_splice_from fs/splice.c:870 [inline]
 [<00000000536a2c3f>] direct_splice_actor+0x126/0x1a0 fs/splice.c:1037
 [<000000005887437d>] splice_direct_to_actor+0x2c8/0x820 fs/splice.c:992
 [<000000009e7f0737>] do_splice_direct+0x1a5/0x260 fs/splice.c:1080
 [<000000002ee6306b>] do_sendfile+0x503/0xc00 fs/read_write.c:1402
 [<0000000036f50d77>] SYSC_sendfile64 fs/read_write.c:1457 [inline]
 [<0000000036f50d77>] SyS_sendfile64+0xd1/0x160 fs/read_write.c:1449
 [<0000000073027324>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<00000000b51d6e62>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<00000000d04fa530>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<00000000d04fa530>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.+..}, at: [<0000000006b48acb>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
2 locks held by getty/2024:
 #0:  (&tty->ldisc_sem){++++++}, at: [<00000000c08809c0>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<0000000042ecc22d>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.0/13017:
 #0:  (sb_writers#4){.+.+.+}, at: [<00000000a60531de>] file_start_write include/linux/fs.h:2646 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<00000000a60531de>] do_sendfile+0x93a/0xc00 fs/read_write.c:1401
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<00000000d24fa2b3>] inode_lock include/linux/fs.h:771 [inline]
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<00000000d24fa2b3>] ext4_file_write_iter+0x111/0xcd0 fs/ext4/file.c:100
2 locks held by syz-executor.0/15531:
 #0:  (sb_writers#4){.+.+.+}, at: [<00000000a60531de>] file_start_write include/linux/fs.h:2646 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<00000000a60531de>] do_sendfile+0x93a/0xc00 fs/read_write.c:1401
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<00000000d24fa2b3>] inode_lock include/linux/fs.h:771 [inline]
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<00000000d24fa2b3>] ext4_file_write_iter+0x111/0xcd0 fs/ext4/file.c:100
2 locks held by syz-executor.0/16933:
 #0:  (sb_writers#4){.+.+.+}, at: [<00000000a60531de>] file_start_write include/linux/fs.h:2646 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<00000000a60531de>] do_sendfile+0x93a/0xc00 fs/read_write.c:1401
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<00000000d24fa2b3>] inode_lock include/linux/fs.h:771 [inline]
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<00000000d24fa2b3>] ext4_file_write_iter+0x111/0xcd0 fs/ext4/file.c:100
2 locks held by kworker/u4:7/20736:
 #0:  ("writeback"){++++.+}, at: [<00000000d0bd37c7>] process_one_work+0x790/0x1600 kernel/workqueue.c:2107
 #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<0000000090dab2de>] process_one_work+0x7ce/0x1600 kernel/workqueue.c:2111
2 locks held by syz-executor.2/25274:
 #0:  (sb_writers#4){.+.+.+}, at: [<00000000a60531de>] file_start_write include/linux/fs.h:2646 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<00000000a60531de>] do_sendfile+0x93a/0xc00 fs/read_write.c:1401
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<00000000108c3a58>] inode_lock include/linux/fs.h:771 [inline]
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<00000000108c3a58>] __generic_file_fsync+0xcd/0x1c0 fs/libfs.c:978

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0
 ffff8801d98d7cc8 ffffffff81b67001 0000000000000000 0000000000000000
 0000000000000000 ffffffff81099d01 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b7229c 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<000000001f64f674>] __dump_stack lib/dump_stack.c:15 [inline]
 [<000000001f64f674>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<000000004187d87f>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<000000006117f514>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<00000000a3d6139d>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<00000000970e91de>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<00000000970e91de>] check_hung_task kernel/hung_task.c:126 [inline]
 [<00000000970e91de>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline]
 [<00000000970e91de>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
 [<0000000064db1cb4>] kthread+0x278/0x310 kernel/kthread.c:211
 [<00000000f3e70406>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8282a0e1

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/10/24 11:33 https://android.googlesource.com/kernel/common android-4.9 7fe05eede1c8 d01bb02a .config console log report ci-android-49-kasan-gce-root
* Struck through repros no longer work on HEAD.