syzbot


INFO: task hung in __fdget_pos

Status: auto-obsoleted due to no activity on 2023/07/29 10:54
Reported-by: syzbot+dffcaad7d9538ed2d23e@syzkaller.appspotmail.com
First crash: 613d, last: 613d
Similar bugs (12)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in __fdget_pos (2) 5 80d 114d 0/3 upstream: reported on 2024/08/11 21:32
upstream INFO: task hung in __fdget_pos kernfs 1 2444d 2444d 0/28 closed as invalid on 2018/03/27 11:08
android-44 INFO: task hung in __fdget_pos 2 2264d 2277d 0/2 auto-closed as invalid on 2019/03/21 05:21
linux-6.1 INFO: task hung in __fdget_pos 1 422d 422d 0/3 auto-obsoleted due to no activity on 2024/01/16 13:13
android-49 INFO: task hung in __fdget_pos 22 2265d 2396d 0/3 auto-closed as invalid on 2019/03/20 03:41
upstream INFO: task hung in __fdget_pos (4) fs C error done 297 64d 457d 0/28 upstream: reported C repro on 2023/09/03 04:11
upstream INFO: task hung in __fdget_pos (3) fs 3 1151d 1168d 0/28 auto-closed as invalid on 2022/01/07 10:38
android-414 INFO: task hung in __fdget_pos 1 2133d 2064d 0/1 auto-closed as invalid on 2019/07/30 11:39
linux-5.15 INFO: task hung in __fdget_pos (2) 2 221d 233d 0/3 auto-obsoleted due to no activity on 2024/08/04 06:39
upstream INFO: task hung in __fdget_pos (2) fs 36 2156d 2381d 0/28 closed as dup on 2018/10/27 13:29
linux-5.15 INFO: task hung in __fdget_pos (3) 50 26d 114d 0/3 upstream: reported on 2024/08/11 10:43
upstream INFO: task can't die in __fdget_pos fs 1 1026d 1026d 0/28 auto-closed as invalid on 2022/04/12 09:48

Sample crash report:
INFO: task syz-executor.2:10576 blocked for more than 144 seconds.
      Not tainted 5.15.105-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:    0 pid:10576 ppid:  4102 flags:0x00000001
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0xf10/0x1e38 kernel/sched/core.c:6372
 schedule+0x11c/0x1c8 kernel/sched/core.c:6455
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6514
 __mutex_lock_common+0xba0/0x2154 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
 __fdget_pos+0xdc/0x108 fs/file.c:1073
 fdget_pos include/linux/file.h:75 [inline]
 ksys_write+0x8c/0x26c fs/read_write.c:638
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:656
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:
4 locks held by kworker/1:1/25:
 #0: ffff0000c0021538 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2279
 #1: ffff8000189e7c00 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2281
 #2: ffff00012754c0e0 (&type->s_umount_key#61){++++}-{3:3}, at: flush_old_commits+0xcc/0x2b8 fs/reiserfs/super.c:97
 #3: ffff0000d4d7f090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
1 lock held by khungtaskd/27:
 #0: ffff800014a91660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:268
2 locks held by kworker/u4:4/333:
2 locks held by getty/3735:
 #0: 
ffff0000d3284098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
 #1: ffff80001a26b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1200 drivers/tty/n_tty.c:2147
7 locks held by syz-executor.2/10568:
1 lock held by syz-executor.2/10576:
 #0: ffff00012c6cd770 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xdc/0x108 fs/file.c:1073
3 locks held by kworker/u4:13/11112:
2 locks held by syz-executor.4/13998:
 #0: ffff00012754c0e0 (&type->s_umount_key#61){++++}-{3:3}, at: iterate_supers+0xb0/0x1dc fs/super.c:703
 #1: 
ffff0000d4d7f090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27

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Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/03/31 10:53 linux-5.15.y c957cbb87315 f325deb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in __fdget_pos
* Struck through repros no longer work on HEAD.