syzbot

INFO: task syz.4.21:6291 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21        state:D stack:27208 pid:6291  tgid:6291  ppid:6264   task_flags:0x480140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 blk_debugfs_lock_nomemsave block/blk.h:740 [inline]
 blk_debugfs_lock block/blk.h:752 [inline]
 blk_trace_setup+0x1f2/0x440 kernel/trace/blktrace.c:788
 blk_trace_ioctl+0x245/0x320 kernel/trace/blktrace.c:937
 blkdev_ioctl+0x17c/0x6f0 block/ioctl.c:793
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f53fd99c819
RSP: 002b:00007ffc2ca88c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f53fdc15fa0 RCX: 00007f53fd99c819
RDX: 00002000000000c0 RSI: 00000000c0481273 RDI: 0000000000000003
RBP: 00007f53fda32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f53fdc15fac R14: 00007f53fdc15fa0 R15: 00007f53fdc15fa0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/32:
 #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:3/49:
 #0: ffff8880b853b360 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x140 kernel/sched/core.c:647
 #1: ffff8880b8524648 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:225 [inline]
 #1: ffff8880b8524648 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2c11/0x6120 kernel/sched/core.c:6905
 #2: ffff8880b8526358 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x124/0x1d0 kernel/time/timer.c:1004
 #3: ffff888155b78168 (&rdev->bss_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
 #3: ffff888155b78168 (&rdev->bss_lock){+.-.}-{3:3}, at: ieee80211_ibss_work+0x153/0x1050 net/mac80211/ibss.c:1651
 #4: ffff8880b853b360 (&rq->__lock){-.-.}-{2:2}, at: finish_lock_switch kernel/sched/core.c:5033 [inline]
 #4: ffff8880b853b360 (&rq->__lock){-.-.}-{2:2}, at: finish_task_switch.isra.0+0x14a/0xb80 kernel/sched/core.c:5153
4 locks held by kworker/u8:7/1294:
2 locks held by getty/5584:
 #0: ffff888038b3a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900033332f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
2 locks held by syz.3.20/6191:
1 lock held by syz.4.21/6291:
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock_nomemsave block/blk.h:740 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock block/blk.h:752 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0x1f2/0x440 kernel/trace/blktrace.c:788
1 lock held by syz.5.22/6322:
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock_nomemsave block/blk.h:740 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock block/blk.h:752 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0x1f2/0x440 kernel/trace/blktrace.c:788
1 lock held by syz.6.23/6416:
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock_nomemsave block/blk.h:740 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock block/blk.h:752 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0x1f2/0x440 kernel/trace/blktrace.c:788
1 lock held by syz.7.24/6510:
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock_nomemsave block/blk.h:740 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock block/blk.h:752 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0x1f2/0x440 kernel/trace/blktrace.c:788
1 lock held by syz.8.25/6537:
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock_nomemsave block/blk.h:740 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock block/blk.h:752 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0x1f2/0x440 kernel/trace/blktrace.c:788
1 lock held by syz.9.26/6632:
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock_nomemsave block/blk.h:740 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock block/blk.h:752 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0x1f2/0x440 kernel/trace/blktrace.c:788
1 lock held by syz.0.27/6746:
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock_nomemsave block/blk.h:740 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_debugfs_lock block/blk.h:752 [inline]
 #0: ffff88802753af00 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0x1f2/0x440 kernel/trace/blktrace.c:788
2 locks held by syz.1.63/7104:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xd25/0x1050 kernel/hung_task.c:515
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 58 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210
Code: 86 0d 5a 00 48 89 df 5b e9 1d 8b 5f 00 be 03 00 00 00 5b e9 e2 69 ec 02 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 65 8b 05 a5 bc 05 12 48 8b 34 24 65 48 8b 15 81 bc 05
RSP: 0018:ffffc900015f7910 EFLAGS: 00000083
RAX: 0000000000000000 RBX: ffff88813fe9a558 RCX: ffffffff81ac70bc
RDX: 0000000000000cae RSI: 0000000000001000 RDI: ffff88801c750000
RBP: ffffffff82683cad R08: 0000000000000007 R09: 0000000000001000
R10: 0000000000000cae R11: 0000000000000000 R12: 0000000000000cae
R13: 8000000002683063 R14: 0000000000000001 R15: 8000000000000063
FS:  0000000000000000(0000) GS:ffff888124440000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffa17b2ba40 CR3: 000000000e598000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __text_poke+0x3ce/0xae0 arch/x86/kernel/alternative.c:2589
 smp_text_poke_batch_finish+0x6b5/0xc60 arch/x86/kernel/alternative.c:3049
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x37a/0x550 kernel/jump_label.c:919
 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate mm/kfence/core.c:900 [inline]
 toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:892
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>