INFO: task syz.0.18279:20939 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.18279 state:D stack:27832 pid:20939 tgid:20936 ppid:15079 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x1709/0x5530 kernel/sched/core.c:7231
__schedule_loop kernel/sched/core.c:7308 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7604
rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
bdev_open+0xde/0xd00 block/bdev.c:991
blkdev_open+0x47f/0x630 block/fops.c:672
do_dentry_open+0x849/0x1420 fs/open.c:947
vfs_open+0x3b/0x350 fs/open.c:1052
do_open fs/namei.c:4694 [inline]
path_openat+0x2e64/0x3850 fs/namei.c:4857
do_file_open+0x23e/0x4a0 fs/namei.c:4886
do_sys_openat2+0x115/0x200 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1385
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe8bb61e68e
RSP: 002b:00007fe8b98b5b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fe8b98b66c0 RCX: 00007fe8bb61e68e
RDX: 0000000000000402 RSI: 00007fe8b98b5c00 RDI: ffffffffffffff9c
RBP: 00007fe8b98b5c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fe8bb8e6038 R14: 00007fe8bb8e5fa0 R15: 00007ffd89a77fc8
Showing all locks held in the system:
locks held by khungtaskd/39: 1, last CPU#0:
#0: ffffffff8e3c3840 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e3c3840 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e3c3840 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6835
locks held by getty/5344: 2, on CPU#1:
#0: ffff8880365f60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by udevd/16701: 1, on CPU#0:
#0: ffff888026de84c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd00 block/bdev.c:991
locks held by syz.0.18279/20939: 1, on CPU#1:
#0: ffff888026de84c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd00 block/bdev.c:991
locks held by kworker/u8:55/22621: 2, last CPU#1:
#0: ffff888032d14938 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff888032d14938 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff888032d14938 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc9000bb4fc60 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc9000bb4fc60 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc9000bb4fc60 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
locks held by syz.1.19030/22848: 3, on CPU#1:
#0: ffff888058bab928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888035ea2510 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2731 [inline]
#1: ffff888035ea2510 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffff88803b259878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 22621 Comm: kworker/u8:55 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:869 [inline]
RIP: 0010:batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:792 [inline]
RIP: 0010:batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:853 [inline]
RIP: 0010:batadv_iv_ogm_schedule+0x65c/0xf90 net/batman-adv/bat_iv_ogm.c:908
Code: 74 11 e8 37 59 b1 f6 e9 88 fe ff ff e8 2d 59 b1 f6 eb 05 e8 26 59 b1 f6 e8 e1 38 39 00 89 c3 31 ff 89 c6 e8 c6 5d b1 f6 85 db <4c> 8b bc 24 98 00 00 00 4c 8b a4 24 90 00 00 00 74 15 e8 ad 0c 96
RSP: 0018:ffffc9000bb4f940 EFLAGS: 00000202
RAX: ffffffff8b13e1da RBX: 0000000000000001 RCX: ffff888063ba3e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000bb4faa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e3c3840 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff888025f56dc0
FS: 0000000000000000(0000) GS:ffff888125b03000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563f178f8660 CR3: 000000000e1b0000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
batadv_iv_send_outstanding_bat_ogm_packet+0x622/0x740 net/batman-adv/bat_iv_ogm.c:1797
process_one_work+0xaaf/0x1480 kernel/workqueue.c:3379
process_scheduled_works kernel/workqueue.c:3462 [inline]
worker_thread+0xb05/0x10d0 kernel/workqueue.c:3543
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245