syzbot


INFO: task hung in fuse_simple_request (3)

Status: upstream: reported on 2025/03/01 01:36
Reported-by: syzbot+b46f8ec1218dbb83850d@syzkaller.appspotmail.com
First crash: 116d, last: 3d05h
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in fuse_simple_request (2) 3 248d 366d 0/3 auto-obsoleted due to no activity on 2025/01/28 01:40
linux-5.15 INFO: task hung in fuse_simple_request 12 608d 706d 0/3 auto-obsoleted due to no activity on 2024/02/03 13:59
upstream INFO: task hung in fuse_simple_request fuse C inconclusive error 273 275d 1654d 0/29 upstream: reported C repro on 2020/12/13 21:13
linux-6.1 INFO: task hung in fuse_simple_request 6 585d 673d 0/3 auto-obsoleted due to no activity on 2024/02/26 14:29
linux-6.1 INFO: task hung in fuse_simple_request (2) 18 16d 369d 0/3 upstream: reported on 2024/06/21 20:45
upstream INFO: task can't die in request_wait_answer fuse C error 14 1226d 1736d 0/29 auto-obsoleted due to no activity on 2023/04/16 22:02

Sample crash report:
INFO: task syz.5.1086:9543 blocked for more than 143 seconds.
      Not tainted 5.15.185-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.1086      state:D stack:27552 pid: 9543 ppid:  5201 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 request_wait_answer fs/fuse/dev.c:411 [inline]
 __fuse_request_send fs/fuse/dev.c:430 [inline]
 fuse_simple_request+0x10e7/0x19c0 fs/fuse/dev.c:515
 fuse_flush+0x522/0x720 fs/fuse/file.c:517
 filp_close+0xac/0x150 fs/open.c:1363
 __range_close fs/file.c:694 [inline]
 __close_range+0x208/0x4d0 fs/file.c:749
 __do_sys_close_range fs/open.c:1408 [inline]
 __se_sys_close_range fs/open.c:1405 [inline]
 __x64_sys_close_range+0x76/0x80 fs/open.c:1405
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f57039fc929
RSP: 002b:00007ffcf62af8f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007f5703c25ba0 RCX: 00007f57039fc929
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f5703c25ba0 R08: 0000000000000090 R09: 00000009f62afbef
R10: 00000000003ffd4c R11: 0000000000000246 R12: 000000000006e1ff
R13: 00007f5703c24080 R14: ffffffffffffffff R15: 00007ffcf62afa10
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:0/7:
 #0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90000cc7d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88801edcc240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x271/0x3240 drivers/net/netdevsim/fib.c:1480
1 lock held by khungtaskd/27:
 #0: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3929:
 #0: ffff88814cb6f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026462e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
3 locks held by kworker/u4:9/4303:
 #0: ffff888016879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000326fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d22a948 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
5 locks held by kworker/u4:11/4305:
 #0: ffff8880169cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900032afd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d21ecd0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:589
 #3: ffffffff8d22a948 (rtnl_mutex){+.+.}-{3:3}, at: ip6gre_exit_batch_net+0xbf/0x490 net/ipv6/ip6_gre.c:1647
 #4: ffffffff8c120a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #4: ffffffff8c120a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845
2 locks held by kworker/0:9/4593:
 #0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000351fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
3 locks held by kworker/0:12/4596:
 #0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900031ffd00 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8c120a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #2: ffffffff8c120a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845
3 locks held by syz-executor/6120:
 #0: ffff888075accff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x5f/0x1030 net/bluetooth/hci_core.c:1737
 #1: ffff888075acc078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x3f4/0x1030 net/bluetooth/hci_core.c:1782
 #2: ffffffff8d370cc8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline]
 #2: ffffffff8d370cc8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622
3 locks held by syz-executor/7771:
 #0: ffff888055a2cff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x5f/0x1030 net/bluetooth/hci_core.c:1737
 #1: ffff888055a2c078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x3f4/0x1030 net/bluetooth/hci_core.c:1782
 #2: ffffffff8d370cc8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline]
 #2: ffffffff8d370cc8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622
1 lock held by syz.7.1435/11627:
 #0: ffffffff8d22a948 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x86b/0xa40 net/core/dev.c:10696
3 locks held by syz.6.1448/11650:
 #0: ffff88807db68ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x5f/0x1030 net/bluetooth/hci_core.c:1737
 #1: ffff88807db68078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x3f4/0x1030 net/bluetooth/hci_core.c:1782
 #2: ffffffff8d370cc8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline]
 #2: ffffffff8d370cc8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4303 Comm: kworker/u4:9 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: phy15 ieee80211_iface_work
RIP: 0010:qlist_put mm/kasan/quarantine.c:60 [inline]
RIP: 0010:kasan_quarantine_put+0xaa/0x220 mm/kasan/quarantine.c:211
Code: 01 fb 31 c0 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f c3 48 8d 80 00 62 03 00 45 8b 76 18 48 83 38 00 74 6f 48 8b 48 08 48 89 19 <48> 89 58 08 48 c7 03 00 00 00 00 4c 03 70 10 4c 89 70 10 49 81 fe
RSP: 0018:ffffc9000326f8b8 EFLAGS: 00000086
RAX: ffff8880b9136200 RBX: ffff88806365a000 RCX: ffff888061f0f800
RDX: 0000000000000000 RSI: ffffffff8a59a720 RDI: ffffffff8a59a6e0
RBP: ffffc9000326f948 R08: ffffffff8100460f R09: 0000000000000001
R10: 00000000cca7791c R11: 0000000031a54a90 R12: ffff888016841dc0
R13: ffff88806365a000 R14: 0000000000000800 R15: 0000000000000286
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9719c11368 CR3: 0000000049c80000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4559
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1615 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x1888/0x29c0 net/mac80211/ibss.c:1643
 ieee80211_iface_process_skb net/mac80211/iface.c:1459 [inline]
 ieee80211_iface_work+0x70e/0xc60 net/mac80211/iface.c:1513
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/22 15:48 linux-5.15.y 1c700860e8bc d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
2025/06/16 20:56 linux-5.15.y 1c700860e8bc d1716036 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
2025/06/10 02:16 linux-5.15.y 1c700860e8bc 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
2025/06/02 03:43 linux-5.15.y 98f47d0e9b8c 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
2025/05/18 21:16 linux-5.15.y a68c15152131 f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
2025/05/17 20:33 linux-5.15.y 3b8db0e4f263 f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
2025/04/07 12:43 linux-5.15.y 0c935c049b5c 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
2025/04/01 20:42 linux-5.15.y 0c935c049b5c b8645499 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
2025/03/01 01:35 linux-5.15.y c16c81c81336 67cf5345 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in fuse_simple_request
* Struck through repros no longer work on HEAD.