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INFO: task hung in fuse_direct_IO (5)

Status: auto-obsoleted due to no activity on 2026/07/09 00:59
Subsystems: kernel
Labels: prio:high
[Documentation on labels]
First crash: 132d, last: 100d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
9a49d7b9-33ec-4740-ac2b-3889adee9954 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ INFO: task hung in fuse_direct_IO (5) 2026/05/17 19:07 2026/05/17 19:07 2026/05/17 19:55 de5aae85e5f28e2fa1c7deefcc24fe286abe5140

			
		
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in fuse_direct_IO 1 1 1610d 1610d 0/1 auto-closed as invalid on 2022/06/20 01:55
upstream INFO: task hung in fuse_direct_IO (3) kernel 1 1 382d 382d 0/29 auto-obsoleted due to no activity on 2025/09/30 10:03
upstream INFO: task hung in fuse_direct_IO fuse 1 1 1019d 1019d 0/29 auto-obsoleted due to no activity on 2024/01/02 16:16
upstream INFO: task hung in fuse_direct_IO (2) fuse 1 3 643d 693d 0/29 auto-obsoleted due to no activity on 2025/01/12 09:59
upstream INFO: task hung in fuse_direct_IO (4) kernel 1 1 290d 290d 0/29 auto-obsoleted due to no activity on 2025/12/01 01:33

Sample crash report:
INFO: task syz.6.5498:27535 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.5498      state:D stack:26904 pid:27535 tgid:27534 ppid:21726  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121
 fuse_direct_IO+0x8e7/0xf10 fs/fuse/file.c:2896
 fuse_direct_write_iter+0x4bb/0x810 fs/fuse/file.c:1796
 fuse_file_write_iter+0x5c5/0x990 fs/fuse/file.c:1845
 aio_write+0x3ba/0x920 fs/aio.c:1633
 __io_submit_one fs/aio.c:2005 [inline]
 io_submit_one+0x1142/0x1fb0 fs/aio.c:2052
 __do_sys_io_submit fs/aio.c:2111 [inline]
 __se_sys_io_submit fs/aio.c:2081 [inline]
 __x64_sys_io_submit+0x1b1/0x3a0 fs/aio.c:2081
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f57b199c819
RSP: 002b:00007f57b2879028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007f57b1c15fa0 RCX: 00007f57b199c819
RDX: 0000200000000780 RSI: 0000000000000004 RDI: 00007f57b27ed000
RBP: 00007f57b1a32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f57b1c16038 R14: 00007f57b1c15fa0 R15: 00007ffc32581f38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e7e7920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e7e7920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e7e7920 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by getty/5574:
 #0: ffff8880396920a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
5 locks held by kworker/u8:9/18435:
1 lock held by syz.6.5498/27535:
 #0: ffff88804cf00848 (&sb->s_type->i_mutex_key#35){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff88804cf00848 (&sb->s_type->i_mutex_key#35){+.+.}-{4:4}, at: fuse_dio_lock fs/fuse/file.c:1434 [inline]
 #0: ffff88804cf00848 (&sb->s_type->i_mutex_key#35){+.+.}-{4:4}, at: fuse_direct_write_iter+0x41f/0x810 fs/fuse/file.c:1791

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xd25/0x1050 kernel/hung_task.c:515
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 98 81 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d a3 41 1a 00 fb f4 <e9> fc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df0 EFLAGS: 00000246
RAX: 000000000530df1b RBX: ffff88801e69a4c0 RCX: ffffffff8b914c75
RDX: 0000000000000000 RSI: ffffffff8de7af61 RDI: ffffffff8c1b1ea0
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10170a679d
R10: ffff8880b8533ceb R11: 0000000000000000 R12: 0000000000000001
R13: ffffed1003cd3498 R14: 0000000000000001 R15: ffffffff90d9d610
FS:  0000000000000000(0000) GS:ffff888124439000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005558f3aa0be0 CR3: 000000000e598000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:73 [inline]
 default_idle+0x9/0x10 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x464/0x590 kernel/sched/idle.c:352
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451
 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x148
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/10 00:57 upstream 8b02520ec5f7 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in fuse_direct_IO
2026/03/09 09:51 upstream 1f318b96cc84 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in fuse_direct_IO
* Struck through repros no longer work on HEAD.