INFO: task hung in tun_chr_close (5)

Status: upstream: reported C repro on 2024/09/15 19:59
Subsystems: net
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+b0ae8f1abf7d891e0426@syzkaller.appspotmail.com
First crash: 784d, last: 6h18m
Cause bisection: introduced by (bisect log) :
commit 5a781ccbd19e4664babcbe4b4ead7aa2b9283d22
Author: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Date: Sat Sep 29 00:59:43 2018 +0000

  tc: Add support for configuring the taprio scheduler

Crash: BUG: unable to handle kernel NULL pointer dereference in taprio_dequeue (log)
Repro: syz .config
  
▶ ▼ ✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision
49315809 patching 💥 INFO: task hung in tun_chr_close (5) 2026/09/02 16:36 2026/09/02 16:36 2026/09/02 16:58 9941e97d
a66775ee patching 💥 INFO: task hung in tun_chr_close (5) 2026/09/01 16:18 2026/09/01 16:18 2026/09/01 16:44 587f6b29
80587f04 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: task hung in tun_chr_close (5) 2026/05/31 07:18 2026/05/31 07:18 2026/05/31 09:48 6b4a8443
54caf62d assessment-security 💥 INFO: task hung in tun_chr_close (5) 2026/05/14 14:38 2026/05/14 14:38 2026/05/14 14:39 6ccb967e
▶ ▼ Discussions (5)
Title Replies (including bot) Last reply
[syzbot] Monthly net report (Aug 2026) 0 (1) 2026/08/25 12:32
[syzbot] Monthly net report (Jul 2026) 0 (1) 2026/07/25 04:32
[syzbot] Monthly net report (Jun 2026) 0 (1) 2026/06/23 20:32
[syzbot] Monthly net report (Apr 2026) 0 (1) 2026/04/22 09:08
[syzbot] [wireguard?] INFO: task hung in tun_chr_close (5) 0 (4) 2026/03/31 17:17
▶ ▼ Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in tun_chr_close 1 40 656d 898d 0/3 auto-obsoleted due to no activity on 2025/02/09 21:18
linux-4.19 INFO: task hung in tun_chr_close 1 1 2213d 2213d 0/1 auto-closed as invalid on 2020/12/09 18:55
linux-6.6 INFO: task hung in tun_chr_close origin:lts-only 1 syz, C error 1 117d 117d 0/2 upstream: reported C repro on 2026/05/09 00:17
upstream INFO: task hung in tun_chr_close (4) net 1 syz unreliable error 14 1754d 1815d 0/29 auto-closed as invalid on 2022/09/18 21:51
upstream INFO: task hung in tun_chr_close net 1 5 2539d 3120d 0/29 closed as dup on 2018/02/16 08:24
linux-4.19 INFO: task hung in tun_chr_close (3) 1 1 1490d 1490d 0/1 auto-obsoleted due to no activity on 2022/12/03 04:48
linux-6.1 INFO: task hung in tun_chr_close 1 31 768d 835d 0/3 auto-obsoleted due to no activity on 2024/10/04 23:47
upstream INFO: task hung in rtnetlink_rcv_msg net 1 syz, C inconclusive inconclusive 1970 786d 2749d 26/29 fixed on 2024/07/09 19:14
android-49 INFO: task hung in tun_chr_close 1 1 3035d 3035d 0/3 auto-closed as invalid on 2019/02/22 14:33
linux-4.19 INFO: task hung in tun_chr_close (4) 1 3 1296d 1324d 0/1 upstream: reported on 2023/01/18 07:05
linux-4.19 INFO: task hung in tun_chr_close (2) 1 6 1702d 1796d 0/1 auto-closed as invalid on 2022/05/04 09:03
linux-6.1 INFO: task hung in tun_chr_close (2) 1 1 246d 246d 0/3 auto-obsoleted due to no activity on 2026/04/09 21:13
upstream INFO: task hung in tun_chr_close (3) net 1 1 1926d 1926d 0/29 auto-closed as invalid on 2021/08/23 13:06
android-44 INFO: task hung in tun_chr_close 1 1 3044d 3044d 0/2 auto-closed as invalid on 2019/02/22 15:23
upstream INFO: task hung in tun_chr_close (2) net 1 7 2035d 2256d 0/29 auto-closed as invalid on 2021/05/17 11:47
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/07/20 22:20 32m retest repro net-next log
2026/07/20 22:20 34m retest repro net log
2026/07/20 22:20 1h48m retest repro net log
2026/07/20 22:20 2h06m retest repro net log
2026/07/20 00:29 21m retest repro upstream error
2026/07/19 22:25 21m retest repro upstream error
2026/07/19 22:25 23m retest repro upstream error
2026/07/19 22:25 22m retest repro upstream error
2026/07/19 22:25 26m retest repro upstream error
2026/07/19 22:25 23m retest repro upstream error

Sample crash report:
INFO: task syz-executor:5802 blocked for more than 144 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22496 pid:5802  tgid:5802  ppid:1      task_flags:0x40054c flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7f7/0x1550 kernel/locking/mutex.c:820
 tun_detach drivers/net/tun.c:634 [inline]
 tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3438
 __fput+0x44f/0xa60 fs/file_table.c:510

Crashes (730):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/20 08:47 net edc502717be1 0909d65f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/03/31 17:16 net 47ab2c12c87a aeea1c72 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/04/12 08:31 net-next 3f3a2aefbc66 38c8e246 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2025/09/04 23:00 upstream 08b06c30a445 d291dd2d .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: task hung in tun_chr_close
2025/08/09 04:06 upstream 37816488247d 32a0e5ed .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: task hung in tun_chr_close
2025/08/05 18:13 upstream 7e161a991ea7 37880f40 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: task hung in tun_chr_close
2025/05/07 12:22 upstream 0d8d44db295c 350f4ffc .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: task hung in tun_chr_close
2025/03/08 21:35 upstream 2a520073e74f 7e3bd60d .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: task hung in tun_chr_close
2024/11/19 01:31 upstream 9fb2cfa4635a 571351cb .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: task hung in tun_chr_close
2024/12/17 17:58 net 7ed2d9158877 c8c15bb2 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/09/02 04:30 upstream 89a312991dc6 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in tun_chr_close
2026/08/29 23:46 upstream 08dbfad3f504 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in tun_chr_close
2026/08/27 07:09 upstream 73e3f0710014 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in tun_chr_close
2026/08/19 17:02 upstream bd5f485f3f02 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in tun_chr_close
2026/08/13 08:32 upstream 3d6d817622b0 67796a05 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in tun_chr_close
2026/08/07 04:13 upstream 0d8395707651 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in tun_chr_close
2026/08/04 03:22 upstream 075b74841bd0 a68cb31b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in tun_chr_close
2026/08/01 01:37 upstream 8ba098e6b6ff 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in tun_chr_close
2026/07/28 14:40 upstream 62cc90241548 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in tun_chr_close
2026/06/28 22:46 upstream 8b69c0475871 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in tun_chr_close
2026/06/20 09:37 upstream 1a3746ccbb0a 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in tun_chr_close
2026/06/02 16:10 upstream 6f3ed7fec72f 62fe1528 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in tun_chr_close
2026/04/09 08:37 upstream 7f87a5ea75f0 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in tun_chr_close
2024/09/11 19:42 upstream 7c6a3a65ace7 9326a104 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in tun_chr_close
2024/09/01 23:27 upstream c9f016e72b5c 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in tun_chr_close
2026/08/27 03:56 upstream 502d45774af0 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in tun_chr_close
2025/03/08 19:03 upstream 2a520073e74f 7e3bd60d .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: task hung in tun_chr_close
2026/09/03 01:56 net 70f3995830d3 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/09/02 13:07 net 70f3995830d3 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/09/02 05:49 net 1d2929d0850f 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/09/01 23:29 net 1d2929d0850f 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/09/01 12:27 net 545b63503c69 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/31 08:12 net 4aa61c88b4e2 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/30 19:10 net 2188569e7e1b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/30 16:12 net 2188569e7e1b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/29 21:08 net 2188569e7e1b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/29 20:02 net 2188569e7e1b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/29 11:49 net 7e1d6caa9c6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/29 09:17 net 7e1d6caa9c6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/28 09:28 net 1b78070aaef6 e2fa417d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/22 07:16 net 4e15e89faac9 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/08/06 01:53 net 9113e98eb7e3 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/07/05 22:17 net d7a8d500d7e4 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/06/25 17:12 net 02f144fbb4c8 432fd51a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/06/19 10:21 net 5c121ee63568 d7ffd47b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/06/10 06:45 net 0aa05daef784 34dab4be .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/06/04 14:07 net 2cdeaba5a108 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/06/03 21:47 net f723ccaff2fb 234057e5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/05/31 04:25 net 78ef59e7a645 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/05/31 01:23 net 78ef59e7a645 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in tun_chr_close
2026/09/02 23:40 net-next c29b37ed7a4d 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/09/02 20:52 net-next c29b37ed7a4d 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/09/01 04:58 net-next 25c1f6111034 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/08/31 00:09 net-next 1b78070aaef6 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/08/28 01:46 net-next 1b78070aaef6 e2fa417d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/08/27 12:30 net-next 91ec20351349 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/08/21 09:08 net-next 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/08/05 02:14 net-next 5b4f243f78a5 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/07/21 08:15 net-next e354f7d60f14 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/06/17 02:37 net-next 72dfa4700f78 0e4b3e40 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/06/12 06:35 net-next 9bbdc7dc4090 e93da63e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/06/11 05:17 net-next c8459ee2fef5 b754d2d8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/06/07 04:50 net-next 903db046d557 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in tun_chr_close
2026/08/30 02:36 linux-next e30626823a40 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in tun_chr_close
2026/08/25 16:00 linux-next a8406e6c0b79 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in tun_chr_close
2026/08/11 22:51 linux-next cc2b5f627e8c 37a258dd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in tun_chr_close
2026/08/10 22:55 linux-next 3d08ff75a47a 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in tun_chr_close
2026/08/09 18:57 linux-next cc2b5f627e8c 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in tun_chr_close
2026/06/14 04:24 linux-next ec039126b7fa 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in tun_chr_close
2026/06/01 17:09 linux-next f7af91adc230 8d8eeb3a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in tun_chr_close
2026/06/01 01:34 linux-next f7af91adc230 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in tun_chr_close
* Struck through repros no longer work on HEAD.