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INFO: task hung in hci_dev_open (2)

Status: upstream: reported syz repro on 2025/02/15 18:20
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+b3b33ad3a3e6369375a7@syzkaller.appspotmail.com
First crash: 486d, last: 53d
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: soft lockup in __do_softirq (log)
Repro: syz .config
  
Fix bisection: the issue occurs on the latest tested release (bisect log)
  
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
b8037257-5fbe-4dfd-8206-11a3e967245e assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: task hung in hci_dev_open (2) 2026/05/31 09:26 2026/05/31 09:26 2026/05/31 10:25 6b4a844333e83556da95d61d7f207e7ef5cd4bc6
dd571a03-0e16-4d4d-82f8-c5e0da2b7377 assessment-security 💥 INFO: task hung in hci_dev_open (2) 2026/05/14 16:02 2026/05/14 16:02 2026/05/14 16:03 6ccb967e465e832a7bfd7a116ad00d52a0923a5d failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 128 From /app/workdir/repo/linux * branch HEAD -> FETCH_HEAD Updating files: 20% (18635/91442) Updating files: 21% (19203/91442) Updating files: 22% (20118/91442) Updating files: 23% (21032/91442) Updating files: 24% (21947/91442) Updating files: 25% (22861/91442) Updating files: 26% (23775/91442) Updating files: 27% (24690/91442) Updating files: 28% (25604/91442) Updating files: 29% (26519/91442) Updating files: 30% (27433/91442) Updating files: 30% (27621/91442) Updating files: 31% (28348/91442) Updating files: 32% (29262/91442) Updating files: 33% (30176/91442) error: unable to write file drivers/char/ipmi/ipmi_watchdog.c error: unable to write file drivers/char/ipmi/kcs_bmc.c error: unable to write file drivers/char/ipmi/kcs_bmc.h error: unable to write file drivers/char/ipmi/kcs_bmc_aspeed.c error: unable to write file drivers/char/ipmi/kcs_bmc_cdev_ipmi.c error: unable to write file drivers/char/ipmi/kcs_bmc_client.h error: unable to write file drivers/char/ipmi/kcs_bmc_device.h error: unable to write file drivers/char/ipmi/kcs_bmc_npcm7xx.c error: unable to write file drivers/char/ipmi/kcs_bmc_serio.c error: unable to write file drivers/char/ipmi/ssif_bmc.c error: unable to write file drivers/char/lp.c error: unable to write file drivers/char/mem.c error: unable to write file drivers/char/misc.c error: unable to write file drivers/char/misc_minor_kunit.c fatal: cannot create directory at 'drivers/char/mwave': No space left on device
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] INFO: task hung in hci_dev_open (2) 0 (1) 2025/02/15 18:20
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in hci_dev_open bluetooth 1 6 1444d 1516d 0/29 auto-closed as invalid on 2022/09/27 19:03
▶ ▼ Last patch testing requests (9)
Created Duration User Patch Repo Result
2026/06/01 23:39 32m retest repro net log
2026/06/01 23:26 25m retest repro net log
2026/05/13 05:12 30m retest repro net-next report log
2026/03/23 21:25 21m retest repro net report log
2026/03/04 02:26 16m retest repro net-next error
2025/12/24 01:50 17m retest repro net error
2025/12/24 01:18 20m retest repro net-next report log
2025/08/02 17:00 3h15m retest repro net-next report log
2025/02/25 22:25 22m retest repro net-next report log
▶ ▼ Fix bisection attempts (5)
Created Duration User Patch Repo Result
2026/01/12 16:26 3h53m bisect fix net OK (0) job log
2025/09/28 00:25 5h02m bisect fix net-next OK (0) job log log
2025/05/21 07:21 2h13m (2) bisect fix net-next OK (0) job log log
2025/04/15 22:20 2h47m bisect fix net-next OK (0) job log log
2025/03/13 18:50 2h22m bisect fix net-next OK (0) job log log

Sample crash report:
INFO: task syz-executor:6137 blocked for more than 152 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:25432 pid:6137  tgid:6137  ppid:1      task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153
 __flush_workqueue+0x6f7/0x14b0 kernel/workqueue.c:4033
 hci_dev_open+0x145/0x300 net/bluetooth/hci_core.c:474
 sock_do_ioctl+0xdc/0x300 net/socket.c:1245
 sock_ioctl+0x576/0x790 net/socket.c:1366
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/05 16:05 net 0373d5c387f2 d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in hci_dev_open
2025/02/11 18:10 net-next ae9b3c0e79bc f2baddf5 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in hci_dev_open
2026/01/27 17:32 upstream fcb70a56f4d8 43e1df1d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in hci_dev_open
2025/12/10 01:06 upstream cb015814f8b6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in hci_dev_open
2025/07/02 16:20 upstream 66701750d556 0cd59a8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in hci_dev_open
2025/06/21 10:53 upstream 11313e2f7812 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in hci_dev_open
2026/04/20 23:25 net f63152958994 e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in hci_dev_open
* Struck through repros no longer work on HEAD.