INFO: task syz.4.773:8937 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.773 state:D stack:25376 pid:8937 tgid:8931 ppid:5867 task_flags:0x400040 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5360 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
__schedule_loop kernel/sched/core.c:7046 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7061
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
bdev_open+0xe0/0xd30 block/bdev.c:945
blkdev_open+0x457/0x600 block/fops.c:694
do_dentry_open+0x953/0x13f0 fs/open.c:965
vfs_open+0x3b/0x340 fs/open.c:1095
do_open fs/namei.c:3895 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4054
do_filp_open+0x1fa/0x410 fs/namei.c:4081
do_sys_openat2+0x121/0x1c0 fs/open.c:1435
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1461
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1e6a78d510
RSP: 002b:00007f1e6b63cb70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000020 RCX: 00007f1e6a78d510
RDX: 0000000000000020 RSI: 00007f1e6b63cc10 RDI: 00000000ffffff9c
RBP: 00007f1e6b63cc10 R08: 0000000000000000 R09: 002364626e2f7665
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007f1e6a9d6308 R14: 00007f1e6a9d6270 R15: 00007ffeefffb2d8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e33d660 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e33d660 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e33d660 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:9/3578:
#0: ffff88813ff09148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88813ff09148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000c637ba0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000c637ba0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
1 lock held by dhcpcd/5528:
#0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
2 locks held by getty/5618:
#0: ffff8880337280a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by udevd/6020:
#0: ffff88802506f358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945
1 lock held by syz.4.773/8937:
#0: ffff88802506f358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945
3 locks held by syz.0.1133/10719:
2 locks held by syz.0.1147/10772:
#0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3433
#1: ffffffff8e3430f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff8e3430f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957
1 lock held by syz.0.1147/10777:
#0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x7a4/0x1150 net/core/dev_ioctl.c:837
1 lock held by syz.0.1147/10807:
#0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8f7452c8 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x7a4/0x1150 net/core/dev_ioctl.c:837
1 lock held by syz.1.1154/10809:
#0: ffffffff8e342fc0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3820
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 10719 Comm: syz.0.1133 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rcu_is_watching+0x70/0xb0 kernel/rcu/tree.c:753
Code: c3 d8 2f c5 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d 39 96 1d 11 74 11 83 e0 04 c1 e8 02 5b <41> 5e 41 5f e9 d7 7a e0 09 cc e8 61 6e 8d ff eb e8 48 c7 c7 40 33
RSP: 0018:ffffc900030f7340 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff9058eb01 RCX: 7e2f866742e6d600
RDX: ffffc900030f7401 RSI: ffffffff8c0381e0 RDI: ffffffff8c0381a0
RBP: dffffc0000000000 R08: ffffc900030f7560 R09: 0000000000000000
R10: ffffc900030f7478 R11: fffff5200061ee91 R12: ffffc900030f7570
R13: ffffc900030f0000 R14: ffffffff8ddeadd0 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8881259e0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff5040fecc CR3: 000000002274c000 CR4: 00000000003526f0
DR0: 0000040000000000 DR1: 0000000000000001 DR2: 0000000000000008
DR3: 0000000000000006 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
class_rcu_destructor include/linux/rcupdate.h:1169 [inline]
unwind_next_frame+0x1965/0x2390 arch/x86/kernel/unwind_orc.c:680
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559
slab_free_hook mm/slub.c:2466 [inline]
slab_free mm/slub.c:6537 [inline]
kmem_cache_free+0x4a4/0x690 mm/slub.c:6648
exit_mmap+0x537/0xb40 mm/mmap.c:1305
__mmput+0x118/0x430 kernel/fork.c:1148
exit_mm+0x1da/0x2c0 kernel/exit.c:582
do_exit+0x648/0x2300 kernel/exit.c:954
do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
get_signal+0x1286/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:40 [inline]
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
irqentry_exit_to_user_mode+0x81/0x120 kernel/entry/common.c:73
exc_page_fault+0xab/0x100 arch/x86/mm/fault.c:1535
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f8a1b78ebb1
Code: Unable to access opcode bytes at 0x7f8a1b78eb87.
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f8a1b9d5fa0 RCX: 00007f8a1b78eba9
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007f8a1b811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f8a1b9d6038 R14: 00007f8a1b9d5fa0 R15: 00007ffe665843a8