INFO: task hung in do_uevent

Status: upstream: reported on 2026/08/04 21:23
Reported-by: syzbot+a250ae8cd98c724fe377@syzkaller.appspotmail.com
First crash: 5d01h, last: 4d20h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in do_uevent 1 2 4d21h 4d21h 0/3 upstream: reported on 2026/08/05 00:48
upstream INFO: task hung in do_uevent prio:high gfs2 1 syz, C 39 19h23m 2d22h 0/29 upstream: reported C repro on 2026/08/07 00:00
linux-6.6 INFO: task hung in do_uevent 1 3 4d21h 5d00h 0/2 upstream: reported on 2026/08/04 22:04

Sample crash report:
INFO: task syz.4.14:4408 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.14        state:D stack:24720 pid:4408  ppid:4275   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 do_uevent+0x1e9/0x490 fs/dlm/lockspace.c:210
 new_lockspace fs/dlm/lockspace.c:659 [inline]
 __dlm_new_lockspace+0x1d6a/0x22b0 fs/dlm/lockspace.c:719
 device_create_lockspace+0xc4/0x350 fs/dlm/user.c:426
 device_write+0x893/0xea0 fs/dlm/user.c:618
 vfs_write+0x2dc/0x9a0 fs/read_write.c:582
 ksys_write+0x14d/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f482079e019
RSP: 002b:00007f48216a7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4820a25fa0 RCX: 00007f482079e019
RDX: 0000000000000078 RSI: 0000200000000400 RDI: 0000000000000007
RBP: 00007f482083500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4820a26038 R14: 00007f4820a25fa0 R15: 00007ffed27ab7d8
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/u4:1/11:
 #0: ffff8880b8e3ad18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538
 #1: ffff8880b8e27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x400/0x740 kernel/sched/psi.c:999
 #2: ffff88807a0a87a8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5693 [inline]
 #2: ffff88807a0a87a8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_wiphy_work+0x31/0x260 net/wireless/core.c:420
 #3: ffff88805df04d40 (&wdev->mtx){+.+.}-{3:3}, at: sdata_lock net/mac80211/ieee80211_i.h:1114 [inline]
 #3: ffff88805df04d40 (&wdev->mtx){+.+.}-{3:3}, at: ieee80211_ibss_work+0xa8/0x1100 net/mac80211/ibss.c:1680
 #4: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #4: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #4: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: ieee80211_sta_active_ibss+0xb1/0x320 net/mac80211/ibss.c:654
 #5: ffff8880b8e3e9e0 (&c->lock){-.-.}-{2:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
 #5: ffff8880b8e3e9e0 (&c->lock){-.-.}-{2:2}, at: put_cpu_partial+0x6e/0x250 mm/slub.c:2639
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
3 locks held by kworker/u4:3/47:
2 locks held by getty/4027:
 #0: ffff88802fa44098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
1 lock held by syz.4.14/4408:
 #0: ffffffff96d4d888 (&ls_lock){+.+.}-{3:3}, at: __dlm_new_lockspace+0xad/0x22b0 fs/dlm/lockspace.c:713
1 lock held by dlm_recoverd/4412:
 #0: ffff88801fe84ca0 (&ls->ls_in_recovery){+.+.}-{3:3}, at: dlm_recoverd+0xa6/0x1df0 fs/dlm/recoverd.c:312

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf0e/0xf50 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 47 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:rcu_is_watching+0x6c/0xa0 kernel/rcu/tree.c:723
Code: c3 08 58 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 2f 8b 03 65 ff 0d 85 46 96 7e 74 0c 83 e0 04 c1 e8 02 5b <41> 5e 41 5f c3 e8 a2 5a 94 ff eb ed 48 c7 c7 00 3a b3 8c 48 89 de
RSP: 0018:ffffc90000b87bc8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 1a821d092b83cd00
RDX: ffff88801a6a5a00 RSI: ffffffff8adf5dc0 RDI: ffffffff8adf5d80
RBP: ffff88801cb914d0 R08: dffffc0000000000 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: dffffc0000000000
R13: ffffffff89f9688e R14: ffffffff8c65f980 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b731d65168 CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_read_lock include/linux/rcupdate.h:792 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0x108/0x600 net/batman-adv/network-coding.c:719
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/05 01:38 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in do_uevent
2026/08/05 01:35 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in do_uevent
2026/08/05 01:17 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in do_uevent
2026/08/04 21:24 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in do_uevent
2026/08/04 21:22 linux-6.1.y fb28aa725e05 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in do_uevent
* Struck through repros no longer work on HEAD.