syzbot


INFO: task hung in f2fs_file_write_iter (5)

Status: auto-obsoleted due to no activity on 2025/09/28 14:58
Subsystems: f2fs
[Documentation on labels]
First crash: 170d, last: 100d
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in f2fs_file_write_iter (3) f2fs 1 4 528d 592d 0/29 auto-obsoleted due to no activity on 2024/07/28 01:00
upstream INFO: task hung in f2fs_file_write_iter (4) f2fs 1 2 388d 392d 0/29 auto-obsoleted due to no activity on 2024/12/14 14:52
linux-4.19 INFO: task hung in f2fs_file_write_iter f2fs 1 5 950d 1054d 0/1 upstream: reported on 2022/11/20 07:00
upstream INFO: task hung in f2fs_file_write_iter f2fs 1 5 853d 950d 0/29 auto-obsoleted due to no activity on 2023/09/06 20:28
upstream INFO: task hung in f2fs_file_write_iter (2) f2fs 1 1 692d 692d 0/29 auto-obsoleted due to no activity on 2024/02/14 19:21

Sample crash report:
INFO: task syz.0.248:8202 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.248       state:D stack:24632 pid:8202  tgid:8201  ppid:7292   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578
 inode_lock include/linux/fs.h:869 [inline]
 f2fs_file_write_iter+0x25a/0x2410 fs/f2fs/file.c:5181
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x548/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f24a1d8e929
RSP: 002b:00007f24a2c5d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f24a1fb5fa0 RCX: 00007f24a1d8e929
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f24a1e10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f24a1fb5fa0 R15: 00007fff3e385088
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13ee20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
3 locks held by kworker/u8:2/36:
 #0: ffff88801ab4d948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801ab4d948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc90000ac7bc0 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000ac7bc0 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffffffff8f4fd488 (rtnl_mutex){+.+.}-{4:4}, at: cfg80211_dfs_channels_update_work+0xb6/0x630 net/wireless/mlme.c:1022
7 locks held by kworker/u8:3/44:
3 locks held by kworker/u8:5/1086:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc900038afbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc900038afbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffffffff8f4fd488 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
1 lock held by udevd/5189:
 #0: ffff8880b8739e18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606
1 lock held by dhcpcd/5484:
 #0: ffffffff8f4fd488 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f4fd488 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x323/0x1b50 net/ipv4/devinet.c:1121
2 locks held by getty/5580:
 #0: ffff888030b930a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/6534:
 #0: ffff888023f3a0e0 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888023f3a0e0 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888023f3a0e0 (&type->s_umount_key#57){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
 #1: ffffffff8e570a48 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1444
4 locks held by kworker/u8:9/8020:
 #0: ffff88801ea8d148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801ea8d148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000bee7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000bee7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffff888023d820e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
 #3: ffff88807bbe5410 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2229 [inline]
 #3: ffff88807bbe5410 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x558/0x750 fs/f2fs/segment.c:463
3 locks held by syz.0.248/8202:
 #0: ffff8880798b7b38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217
 #1: ffff888023d82428 (sb_writers#16){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline]
 #1: ffff888023d82428 (sb_writers#16){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682
 #2: ffff888055c23fd8 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #2: ffff888055c23fd8 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: f2fs_file_write_iter+0x25a/0x2410 fs/f2fs/file.c:5181
5 locks held by syz.0.248/8216:
2 locks held by syz.5.407/9774:
 #0: ffff888023d820e0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
 #0: ffff888023d820e0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
 #1: ffff88802514c7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline]
 #1: ffff88802514c7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831
1 lock held by syz-executor/10553:
 #0: ffffffff8f4fd488 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x37a/0x1df0 drivers/net/tun.c:3038
1 lock held by syz-executor/10555:
 #0: ffffffff8f4fd488 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f4fd488 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:979

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc4-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5140 Comm: kworker/u9:1 Not tainted 6.16.0-rc4-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci6 hci_cmd_timeout
RIP: 0010:rcu_read_lock include/linux/rcupdate.h:839 [inline]
RIP: 0010:select_task_rq_fair+0x2fd/0x3570 kernel/sched/fair.c:8620
Code: 41 83 fd 08 0f 83 cd 0f 00 00 45 89 ee 44 89 e8 c1 e8 06 48 8d 3c c3 be 08 00 00 00 e8 bc 89 8c 00 4c 0f a3 33 0f 93 44 24 10 <e8> 7e a9 12 00 48 8d 05 00 00 00 00 48 c7 c7 20 ee 13 8e 31 f6 31
RSP: 0018:ffffc90000007bf8 EFLAGS: 00000046
RAX: 0000000000000006 RBX: 0000000000000006 RCX: 0000000000000003
RDX: ffff888079a43c00 RSI: ffffffff8b8a7560 RDI: ffffffff8be1b900
RBP: 0000000000000006 R08: ffffffff8f9fdaf7 R09: 1ffffffff1f3fb5e
R10: dffffc0000000000 R11: ffffffff81951b60 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff888035c61e58 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125c84000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7732381178 CR3: 000000007acb4000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 select_task_rq kernel/sched/core.c:3597 [inline]
 try_to_wake_up+0x51e/0x1290 kernel/sched/core.c:4327
 hrtimer_wakeup+0x4e/0x60 kernel/time/hrtimer.c:1997
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2061 [inline]
RIP: 0010:vprintk_emit+0x58f/0x7a0 kernel/printk/printk.c:2449
Code: 85 32 01 00 00 e8 e1 63 1f 00 41 89 df 4d 85 f6 48 8b 1c 24 75 07 e8 d0 63 1f 00 eb 06 e8 c9 63 1f 00 fb 48 c7 c7 a0 30 13 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 b9 36
RSP: 0018:ffffc9000fbdf720 EFLAGS: 00000293
RAX: ffffffff81a0e9c7 RBX: ffffffff81a0e884 RCX: ffff888035c61e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e1330a0
RBP: ffffc9000fbdf830 R08: ffffffff8f9fdaf7 R09: 1ffffffff1f3fb5e
R10: dffffc0000000000 R11: fffffbfff1f3fb5f R12: dffffc0000000000
R13: 1ffff92001f7bee8 R14: 0000000000000200 R15: 0000000000000023
 _printk+0xcf/0x120 kernel/printk/printk.c:2475
 bt_err+0x10b/0x160 net/bluetooth/lib.c:296
 hci_cmd_timeout+0xff/0x1e0 net/bluetooth/hci_core.c:1475
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/30 14:54 upstream d0b3b7b22dfa fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in f2fs_file_write_iter
2025/05/09 15:42 upstream 9c69f8884904 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in f2fs_file_write_iter
2025/04/22 02:20 upstream 9d7a0577c9db 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in f2fs_file_write_iter
* Struck through repros no longer work on HEAD.