INFO: task rcu_tasks_kthre:12 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:28256 pid:12 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x2c2/0x590 kernel/sched/completion.c:138 __synchronize_srcu+0x2b3/0x350 kernel/rcu/srcutree.c:1243 rcu_tasks_wait_gp+0x49f/0xac0 kernel/rcu/tasks.h:693 rcu_tasks_one_gp+0xd27/0xef0 kernel/rcu/tasks.h:534 rcu_tasks_kthread+0x6e/0x90 kernel/rcu/tasks.h:562 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Showing all locks held in the system: 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 2 locks held by getty/4025: #0: ffff88814cea2098 (&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 2 locks held by kworker/1:2/13411: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc9000497fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 1 lock held by syz.1.10160/2281: #0: ffffffff8cb82e28 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239 2 locks held by syz.5.10161/2283: #0: ffffffff8cb82e28 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239 #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962 4 locks held by syz.5.10161/2285: 2 locks held by syz.3.10162/2292: #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3495 #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962 1 lock held by syz.0.10163/2291: #0: ffff888071ce0e10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #0: ffff888071ce0e10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline] #0: ffff888071ce0e10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1400 3 locks held by syz.1.10160/2301: ============================================= 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: 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2285 Comm: syz.5.10161 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline] RIP: 0010:native_apic_msr_write+0x35/0x50 arch/x86/include/asm/apic.h:206 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 9f 29 06 03 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffc90000007e60 EFLAGS: 00000046 RAX: 0000000000000088 RBX: 0000000000000088 RCX: 0000000000000838 RDX: 0000000000000000 RSI: 0000000000000088 RDI: 0000000000000838 RBP: 0000000000000000 R08: ffffffff8e210aef R09: 1ffffffff1c4215d R10: dffffc0000000000 R11: fffffbfff1c4215e R12: dffffc0000000000 R13: 0000000010006804 R14: ffffffff8c65fb40 R15: dffffc0000000000 FS: 00007fa50c7df6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0b523d5d58 CR3: 00000000622c3000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000b6e DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: apic_write arch/x86/include/asm/apic.h:394 [inline] lapic_next_event+0x5b/0x70 arch/x86/kernel/apic/apic.c:478 clockevents_program_event+0x1bc/0x310 kernel/time/clockevents.c:334 hrtimer_interrupt+0x561/0x980 kernel/time/hrtimer.c:1890 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:__list_add include/linux/list.h:69 [inline] RIP: 0010:list_add_tail include/linux/list.h:102 [inline] RIP: 0010:xdp_recv_frames net/bpf/test_run.c:254 [inline] RIP: 0010:xdp_test_run_batch net/bpf/test_run.c:334 [inline] RIP: 0010:bpf_test_run_xdp_live+0x16d3/0x1a90 net/bpf/test_run.c:362 Code: 05 e8 c1 54 64 f9 4b 8b 34 37 48 89 df 48 8b 54 24 28 e8 b0 e8 d4 ff 48 85 c0 74 83 49 89 c4 48 89 c3 4c 8b ac 24 48 02 00 00 <4c> 89 e7 4c 89 ee 48 8d 94 24 40 02 00 00 e8 1a 10 ab fb 84 c0 0f RSP: 0018:ffffc9000d52f880 EFLAGS: 00000286 RAX: ffff888043ed0a00 RBX: ffff888043ed0a00 RCX: dffffc0000000000 RDX: 0000000000000001 RSI: ffffffff8a8c2920 RDI: ffffffff8adf5de0 RBP: ffffc9000d52fbb0 R08: ffffffff8e210aef R09: 1ffffffff1c4215d R10: dffffc0000000000 R11: fffffbfff1c4215e R12: ffff888043ed0a00 R13: ffff888043ed08c0 R14: 0000000000000120 R15: ffff88805786d400 bpf_prog_test_run_xdp+0x757/0xf80 net/bpf/test_run.c:1457 bpf_prog_test_run+0x31c/0x390 kernel/bpf/syscall.c:3695 __sys_bpf+0x62b/0x780 kernel/bpf/syscall.c:5050 __do_sys_bpf kernel/bpf/syscall.c:5136 [inline] __se_sys_bpf kernel/bpf/syscall.c:5134 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5134 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: 0033:0x7fa50b99e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa50c7df028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fa50bc25fa0 RCX: 00007fa50b99e0d9 RDX: 0000000000000048 RSI: 0000200000000600 RDI: 000000000000000a RBP: 00007fa50ba35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa50bc26038 R14: 00007fa50bc25fa0 R15: 00007ffd40db53b8