INFO: task rcu_tasks_kthre:11 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:rcu_tasks_kthre state:D stack:27984 pid:   11 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __synchronize_srcu+0x2b5/0x350 kernel/rcu/srcutree.c:930
 rcu_tasks_wait_gp+0x43b/0x8e0 kernel/rcu/tasks.h:327
 rcu_tasks_kthread+0x2c1/0x640 kernel/rcu/tasks.h:226
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8d11efa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:4/1408:
3 locks held by kworker/1:3/2301:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000642fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #2: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
2 locks held by getty/3941:
 #0: ffff88802d46e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
2 locks held by kworker/1:6/4322:
 #0: ffff888017872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000334fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
2 locks held by syz.2.2781/15542:
2 locks held by syz.2.2795/15620:
 #0: ffffffff8d16c808 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239
 #1: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #1: ffffffff8d123a28 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 15542 Comm: syz.2.2781 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:380 [inline]
RIP: 0010:__rcu_read_unlock+0x2e/0xd0 kernel/rcu/tree_plugin.h:419
Code: 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3d a5 fd 9c 7e 48 8d 9f 3c 04 00 00 49 89 dc 49 c1 ec 03 43 0f b6 04 3c <84> c0 75 48 ff 0b 75 1d 4c 8d b7 40 04 00 00 4c 89 f0 48 c1 e8 03
RSP: 0018:ffffc9000340ecc0 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: ffff88801c74043c RCX: 7f9558246d294300
RDX: 0000000000000000 RSI: ffffffff8a7a4b20 RDI: ffff88801c740000
RBP: 0000000000000cc0 R08: dffffc0000000000 R09: 1ffffffff2202a18
R10: dffffc0000000000 R11: fffffbfff2202a19 R12: 1ffff110038e8087
R13: dffffc0000000000 R14: ffff88802c328054 R15: dffffc0000000000
FS:  00007fc7564a06c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc756503990 CR3: 00000000596ef000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 percpu_ref_put_many include/linux/percpu-refcount.h:324 [inline]
 percpu_ref_put+0xcc/0x150 include/linux/percpu-refcount.h:338
 css_put include/linux/cgroup.h:405 [inline]
 __mem_cgroup_charge+0x52/0x80 mm/memcontrol.c:6808
 mem_cgroup_charge include/linux/memcontrol.h:700 [inline]
 shmem_add_to_page_cache+0xa8a/0x14d0 mm/shmem.c:718
 shmem_getpage_gfp+0x1735/0x2c10 mm/shmem.c:1940
 shmem_getpage mm/shmem.c:151 [inline]
 shmem_write_begin+0xcd/0x1a0 mm/shmem.c:2474
 generic_perform_write+0x2b6/0x550 mm/filemap.c:3785
 __generic_file_write_iter+0x261/0x4e0 mm/filemap.c:3912
 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944
 __kernel_write+0x522/0x980 fs/read_write.c:539
 __dump_emit+0x258/0x380 fs/coredump.c:943
 dump_user_range+0x84/0x340 fs/coredump.c:1017
 elf_core_dump+0x2fe0/0x3530 fs/binfmt_elf.c:2285
 do_coredump+0x14e8/0x2a40 fs/coredump.c:894
 get_signal+0x531/0x12e0 kernel/signal.c:2899
 arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:157 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:217
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:323
 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1499
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x3288803e49
Code: Unable to access opcode bytes at RIP 0x3288803e1f.
RSP: 002b:00002000000002f8 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007fc758533270 RCX: 00007fc7582ab559
RDX: 0000200000000300 RSI: 00002000000002f0 RDI: 0000000000000000
RBP: 00007fc758342ab8 R08: 0000200000000380 R09: 0000200000000380
R10: 0000200000000340 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc758533308 R14: 00007fc758533270 R15: 00007ffe3e412de8
 </TASK>