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INFO: task hung in tun_chr_close

Status: upstream: reported on 2024/03/18 08:54
Reported-by: syzbot+2eab79fff656b2e85a6a@syzkaller.appspotmail.com
First crash: 40d, last: 40d
▶ ▼ Similar bugs (11)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in tun_chr_close 1 1354d 1354d 0/1 auto-closed as invalid on 2020/12/09 18:55
upstream INFO: task hung in tun_chr_close (4) net syz unreliable error 14 896d 956d 0/26 auto-closed as invalid on 2022/09/18 21:51
upstream INFO: task hung in tun_chr_close net 5 1680d 2262d 0/26 closed as dup on 2018/02/16 08:24
linux-4.19 INFO: task hung in tun_chr_close (3) 1 631d 631d 0/1 auto-obsoleted due to no activity on 2022/12/03 04:48
upstream INFO: task hung in rtnetlink_rcv_msg net C inconclusive inconclusive 913 46d 1890d 0/26 upstream: reported C repro on 2019/02/22 17:00
android-49 INFO: task hung in tun_chr_close 1 2176d 2176d 0/3 auto-closed as invalid on 2019/02/22 14:33
linux-4.19 INFO: task hung in tun_chr_close (4) 3 437d 465d 0/1 upstream: reported on 2023/01/18 07:05
linux-4.19 INFO: task hung in tun_chr_close (2) 6 844d 938d 0/1 auto-closed as invalid on 2022/05/04 09:03
upstream INFO: task hung in tun_chr_close (3) net 1 1068d 1068d 0/26 auto-closed as invalid on 2021/08/23 13:06
android-44 INFO: task hung in tun_chr_close 1 2186d 2186d 0/2 auto-closed as invalid on 2019/02/22 15:23
upstream INFO: task hung in tun_chr_close (2) net 7 1176d 1397d 0/26 auto-closed as invalid on 2021/05/17 11:47

Sample crash report:
INFO: task syz-executor.4:6831 blocked for more than 143 seconds.
      Not tainted 5.15.152-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:21080 pid: 6831 ppid:     1 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6518
 __mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 tun_detach drivers/net/tun.c:699 [inline]
 tun_chr_close+0x3a/0x1b0 drivers/net/tun.c:3435
 __fput+0x3bf/0x890 fs/file_table.c:280
 task_work_run+0x129/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0x6a3/0x2480 kernel/exit.c:872
 do_group_exit+0x144/0x310 kernel/exit.c:994
 __do_sys_exit_group kernel/exit.c:1005 [inline]
 __se_sys_exit_group kernel/exit.c:1003 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1003
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f3119c87da9
RSP: 002b:00007ffd6e02d348 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3119c87da9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007f3119cd444b R08: 00007ffd6e02b0e6 R09: 000000000005712a
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000001c
R13: 000000000005712a R14: 0000000000056d53 R15: 000000000000001e
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/1:0/21:
 #0: ffff888011c71938 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90000db7d20 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x7f/0xb70 net/wireless/reg.c:2436
1 lock held by khungtaskd/27:
 #0: ffffffff8c91f720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
5 locks held by kworker/u4:3/396:
 #0: ffff8880143d4938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90002c17d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff88807f03e0e0 (&type->s_umount_key#32){++++}-{3:3}, at: trylock_super+0x1b/0xf0 fs/super.c:418
 #3: ffff88807f040bd8 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2677
 #4: ffff88807f042990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12b9/0x1570 fs/jbd2/transaction.c:462
3 locks held by kworker/1:2/1066:
 #0: ffff88814a722138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90005207d20 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4655
2 locks held by getty/3255:
 #0: ffff888024a46098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002bab2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
3 locks held by kworker/u4:6/3636:
4 locks held by kworker/u4:8/4180:
 #0: ffff888011dcd138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc9000b63fd20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8d9cfe50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf1/0xb60 net/core/net_namespace.c:558
 #3: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0xa4f/0xc40 net/core/dev.c:10652
1 lock held by syz-executor.4/6831:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3a/0x1b0 drivers/net/tun.c:3435
3 locks held by kworker/0:12/7317:
 #0: ffff888011c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc900051e7d20 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
2 locks held by kworker/0:13/7318:
 #0: ffff888011c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc900051f7d20 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
2 locks held by syz-executor.2/7858:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3a/0x1b0 drivers/net/tun.c:3435
 #1: ffffffff8c923ce8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c923ce8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x280/0x740 kernel/rcu/tree_exp.h:845
1 lock held by syz-executor.1/8047:
 #0: ffff88807f040bd8 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2677
1 lock held by syz-executor.1/8061:
1 lock held by syz-executor.2/8065:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5626
1 lock held by syz-executor.1/8088:
1 lock held by syz-executor.1/8108:
2 locks held by syz-executor.0/8119:
1 lock held by syz-executor.1/8125:
1 lock held by syz-executor.4/8131:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5626
2 locks held by syz-executor.0/8145:
2 locks held by syz-executor.1/8149:
1 lock held by syz-executor.1/8157:
1 lock held by syz-executor.0/8161:
2 locks held by syz-executor.0/8178:
 #0: ffff88807f040bd8 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2677
 #1: ffff88807f042990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x12b9/0x1570 fs/jbd2/transaction.c:462
1 lock held by syz-executor.1/8211:
 #0: ffff88807f040bd8 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2677
1 lock held by syz-executor.0/8216:
 #0: ffff88807f040bd8 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2677
3 locks held by syz-executor.1/8257:
3 locks held by syz-executor.1/8280:
1 lock held by syz-executor.0/8309:
1 lock held by syz-executor.0/8630:
1 lock held by syz-executor.0/8647:
1 lock held by syz-executor.0/8661:
1 lock held by syz-executor.0/8679:
2 locks held by syz-executor.1/8688:
1 lock held by syz-executor.3/8701:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3a/0x1b0 drivers/net/tun.c:3435
1 lock held by syz-executor.0/8705:
1 lock held by syz-executor.3/8711:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5626
1 lock held by syz-executor.1/8718:
1 lock held by syz-executor.0/8728:
1 lock held by syz-executor.1/8746:
3 locks held by syz-executor.0/8768:
1 lock held by syz-executor.0/8778:
1 lock held by syz-executor.1/8787:
 #0: ffff88807f040bd8 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x1f6/0x3d10 fs/ext4/inode.c:2677
1 lock held by syz-executor.2/8803:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5626
1 lock held by syz-executor.0/8805:
1 lock held by syz-executor.0/8819:
2 locks held by syz-executor.1/8830:
1 lock held by syz-executor.4/8840:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5626
2 locks held by syz-executor.0/8997:
4 locks held by syz-executor.0/9118:
4 locks held by syz-executor.1/9120:
4 locks held by syz-executor.1/9130:
4 locks held by syz-executor.0/9134:
2 locks held by syz-executor.0/9143:
2 locks held by syz-executor.1/9149:
2 locks held by syz-executor.1/9159:
4 locks held by syz-executor.0/9164:
2 locks held by syz-executor.0/9173:
4 locks held by syz-executor.0/9177:
4 locks held by syz-executor.1/9183:
2 locks held by syz-executor.0/9196:
2 locks held by syz-executor.1/9439:
1 lock held by syz-executor.3/9453:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5626
3 locks held by syz-executor.0/9457:
4 locks held by syz-executor.1/9467:
4 locks held by syz-executor.1/9566:
3 locks held by syz-executor.0/9703:
3 locks held by syz-executor.0/9713:
1 lock held by syz-executor.2/9726:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5626
1 lock held by syz-executor.4/9849:
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d9dba08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5626

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8787 Comm: syz-executor.1 Not tainted 5.15.152-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
RIP: 0010:lock_is_held_type+0xa/0x180 kernel/locking/lockdep.c:5651
Code: 48 c7 c6 e0 13 8b 8a e8 d4 19 30 f7 0f 0b eb bf e8 ab fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 55 41 57 41 56 41 55 41 54 53 <48> 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 bd ff ff ff
RSP: 0018:ffffc90003a8ee90 EFLAGS: 00000286
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff888018ec8000
RDX: ffff888018ec8000 RSI: 00000000ffffffff RDI: ffff88805a4118d8
RBP: ffff88805a4118d8 R08: ffffffff81a89244 R09: fffff940001968a7
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90003a8ef80
R13: 1ffff92000751df0 R14: ffffea0000cb4500 R15: ffff88807050b180
FS:  0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5d67b7f978 CR3: 0000000061d0a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lock_is_held include/linux/lockdep.h:287 [inline]
 xa_entry include/linux/xarray.h:1182 [inline]
 xas_reload+0xfd/0x470 include/linux/xarray.h:1558
 find_get_entry mm/filemap.c:1996 [inline]
 find_get_pages_range+0x3d5/0x780 mm/filemap.c:2163
 pagevec_lookup_range+0x2e/0x70 mm/swap.c:1104
 mpage_release_unused_pages+0x30b/0x9a0 fs/ext4/inode.c:1581
 ext4_writepages+0x2c66/0x3d10 fs/ext4/inode.c:2835
 do_writepages+0x481/0x730 mm/page-writeback.c:2364
 filemap_fdatawrite_wbc+0x1d6/0x230 mm/filemap.c:400
 __filemap_fdatawrite_range mm/filemap.c:433 [inline]
 __filemap_fdatawrite mm/filemap.c:439 [inline]
 filemap_flush+0x10c/0x150 mm/filemap.c:466
 ext4_release_file+0x7d/0x300 fs/ext4/file.c:141
 __fput+0x3bf/0x890 fs/file_table.c:280
 task_work_run+0x129/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0x6a3/0x2480 kernel/exit.c:872
 do_group_exit+0x144/0x310 kernel/exit.c:994
 get_signal+0xc66/0x14e0 kernel/signal.c:2889
 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:172
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
 irqentry_exit_to_user_mode+0x5/0x40 kernel/entry/common.c:314
 exc_page_fault+0x342/0x740 arch/x86/mm/fault.c:1544
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
RIP: 0033:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 002b:00000000200001b8 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f396faacf80 RCX: 00007f396f97eda9
RDX: 00000000200001c0 RSI: 00000000200001b0 RDI: 0000000008003080
RBP: 00007f396f9cb47a R08: 0000000020000240 R09: 0000000020000240
R10: 0000000020000200 R11: 0000000000000202 R12: 0000000000000000
R13: 000000000000000b R14: 00007f396faacf80 R15: 00007ffeb8375788
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/18 08:53 linux-5.15.y b95c01af2113 d615901c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: task hung in tun_chr_close
* Struck through repros no longer work on HEAD.