syzbot


INFO: task hung in exfat_lookup (2)

Status: auto-obsoleted due to no activity on 2024/10/05 08:40
Subsystems: exfat
[Documentation on labels]
First crash: 468d, last: 284d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in exfat_lookup (3) exfat C done done 7 104d 109d 0/28 auto-obsoleted due to no activity on 2025/04/13 03:04
upstream INFO: task hung in exfat_lookup exfat 1 575d 575d 0/28 auto-obsoleted due to no activity on 2023/12/19 10:59

Sample crash report:
INFO: task syz.0.39:5449 blocked for more than 143 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00215-g22f902dfc51e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.39        state:D stack:26488 pid:5449  tgid:5433  ppid:5084   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x1796/0x49d0 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 exfat_lookup+0x140/0x18f0 fs/exfat/namei.c:700
 lookup_open fs/namei.c:3483 [inline]
 open_last_lookups fs/namei.c:3574 [inline]
 path_openat+0x11c0/0x35f0 fs/namei.c:3810
 do_filp_open+0x235/0x490 fs/namei.c:3840
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1413
 do_sys_open fs/open.c:1428 [inline]
 __do_sys_openat fs/open.c:1444 [inline]
 __se_sys_openat fs/open.c:1439 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1439
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f014c175bd9
RSP: 002b:00007f014cfa3048 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f014c304110 RCX: 00007f014c175bd9
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c
RBP: 00007f014c1e4aa1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f014c304110 R15: 00007fff702864b8
 </TASK>
INFO: task syz.0.39:5452 blocked for more than 143 seconds.
      Not tainted 6.10.0-rc6-syzkaller-00215-g22f902dfc51e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.39        state:D stack:27392 pid:5452  tgid:5433  ppid:5084   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x1796/0x49d0 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178
 __down_write_common+0x1af/0x200 kernel/locking/rwsem.c:1306
 inode_lock include/linux/fs.h:791 [inline]
 chown_common+0x3e1/0x850 fs/open.c:780
 do_fchownat+0x16d/0x250 fs/open.c:821
 __do_sys_lchown fs/open.c:846 [inline]
 __se_sys_lchown fs/open.c:844 [inline]
 __x64_sys_lchown+0x85/0xa0 fs/open.c:844
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f014c175bd9
RSP: 002b:00007f014cf82048 EFLAGS: 00000246 ORIG_RAX: 000000000000005e
RAX: ffffffffffffffda RBX: 00007f014c3041e8 RCX: 00007f014c175bd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000240
RBP: 00007f014c1e4aa1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f014c3041e8 R15: 00007fff702864b8
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u8:0/11:
1 lock held by khungtaskd/30:
 #0: ffffffff8e333f20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e333f20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e333f20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
6 locks held by kworker/u8:5/1087:
 #0: ffff888015ed3148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3223 [inline]
 #0: ffff888015ed3148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3329
 #1: ffffc900045d7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3224 [inline]
 #1: ffffc900045d7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3329
 #2: ffffffff8f5c80d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:594
 #3: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: wg_netns_pre_exit+0x1f/0x1e0 drivers/net/wireguard/device.c:414
 #4: ffff888065e69408 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_netns_pre_exit+0xba/0x1e0 drivers/net/wireguard/device.c:419
 #5: ffffffff8e3392f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #5: ffffffff8e3392f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:939
3 locks held by kworker/u8:9/2859:
 #0: ffff88802affe148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3223 [inline]
 #0: ffff88802affe148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3329
 #1: ffffc90009d67d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3224 [inline]
 #1: ffffc90009d67d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3329
 #2: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4193
1 lock held by dhcpcd/4748:
 #0: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x842/0x1180 net/core/rtnetlink.c:6632
2 locks held by getty/4840:
 #0: ffff88802bb470a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900031432f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2211
3 locks held by kworker/0:4/5140:
 #0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3223 [inline]
 #0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3329
 #1: ffffc90004197d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3224 [inline]
 #1: ffffc90004197d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3329
 #2: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276
3 locks held by syz.0.39/5434:
2 locks held by syz.0.39/5449:
 #0: ffff88807ba702b8 (&sb->s_type->i_mutex_key#28){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:801 [inline]
 #0: ffff88807ba702b8 (&sb->s_type->i_mutex_key#28){++++}-{3:3}, at: open_last_lookups fs/namei.c:3573 [inline]
 #0: ffff88807ba702b8 (&sb->s_type->i_mutex_key#28){++++}-{3:3}, at: path_openat+0x7da/0x35f0 fs/namei.c:3810
 #1: ffff8880601b60e0 (&sbi->s_lock#2){+.+.}-{3:3}, at: exfat_lookup+0x140/0x18f0 fs/exfat/namei.c:700
2 locks held by syz.0.39/5452:
 #0: ffff888066ba8420 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409
 #1: ffff88807ba702b8 (&sb->s_type->i_mutex_key#28){++++}-{3:3}, at: inode_lock include/linux/fs.h:791 [inline]
 #1: ffff88807ba702b8 (&sb->s_type->i_mutex_key#28){++++}-{3:3}, at: chown_common+0x3e1/0x850 fs/open.c:780
1 lock held by syz-executor/7276:
 #0: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x842/0x1180 net/core/rtnetlink.c:6632
7 locks held by syz-executor/7297:
 #0: ffff88801e498420 (sb_writers#8){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2854 [inline]
 #0: ffff88801e498420 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x227/0xc90 fs/read_write.c:586
 #1: ffff88802b1ad088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1eb/0x500 fs/kernfs/file.c:325
 #2: ffff888023bb0968 (kn->active#49){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x20f/0x500 fs/kernfs/file.c:326
 #3: ffffffff8eee1f48 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xfc/0x480 drivers/net/netdevsim/bus.c:216
 #4: ffff888025a9c0e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1009 [inline]
 #4: ffff888025a9c0e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1093 [inline]
 #4: ffff888025a9c0e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xce/0x7c0 drivers/base/dd.c:1290
 #5: ffff888025a9e250 (&devlink->lock_key#10){+.+.}-{3:3}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1672
 #6: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: unregister_netdevice_notifier_net+0x89/0x3a0 net/core/dev.c:1913
1 lock held by syz-executor/7471:
 #0: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8f5d4908 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x842/0x1180 net/core/rtnetlink.c:6632

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

NMI backtrace for cpu 0
CPU: 0 PID: 30 Comm: khungtaskd Not tainted 6.10.0-rc6-syzkaller-00215-g22f902dfc51e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xfde/0x1020 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 25 Comm: kworker/1:0 Not tainted 6.10.0-rc6-syzkaller-00215-g22f902dfc51e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: events_power_efficient wg_ratelimiter_gc_entries
RIP: 0010:check_preemption_disabled+0x4/0x120 lib/smp_processor_id.c:13
Code: 8c 48 c7 c6 e0 15 1f 8c eb 1c 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 41 56 <41> 54 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 65
RSP: 0018:ffffc900001f79e0 EFLAGS: 00000046
RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffff8880176e9e00
RDX: 0000000000000000 RSI: ffffffff8bcaccc0 RDI: ffffffff8c1f1600
RBP: 0000000000000002 R08: ffffffff8edc3d23 R09: 1ffffffff1db87a4
R10: dffffc0000000000 R11: fffffbfff1db87a5 R12: 0000000000000246
R13: ffff8880176e9e00 R14: 00000000ffffffff R15: ffffffff8e333ea0
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555561f93608 CR3: 000000000e132000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
 lock_is_held_type+0x101/0x190 kernel/locking/lockdep.c:5826
 lock_is_held include/linux/lockdep.h:231 [inline]
 __might_resched+0xf4/0x780 kernel/sched/core.c:10158
 wg_ratelimiter_gc_entries+0x3cd/0x470 drivers/net/wireguard/ratelimiter.c:78
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329
 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/07/07 08:39 upstream 22f902dfc51e 2a40360c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in exfat_lookup
2024/06/13 11:58 upstream 2ccbdf43d5e7 2aa5052f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in exfat_lookup
2024/05/07 18:11 upstream dccb07f2914c cb2dcc0e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in exfat_lookup
2024/04/27 18:44 upstream 5eb4573ea63d 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in exfat_lookup
2024/04/20 13:12 upstream 13a2e429f644 af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in exfat_lookup
2024/02/02 05:41 upstream 5c24e4e9e708 d61103fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in exfat_lookup
2024/01/04 16:20 upstream ac865f00af29 28c42cff .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in exfat_lookup
2024/03/27 01:51 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 707081b61156 454571b6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in exfat_lookup
* Struck through repros no longer work on HEAD.