INFO: task syz.3.1064:9018 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.1064 state:D stack:24552 pid:9018 ppid:5774 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 perf_pending_task_sync kernel/events/core.c:5236 [inline] _free_event+0x176/0xfb0 kernel/events/core.c:5242 put_event kernel/events/core.c:5370 [inline] perf_event_release_kernel+0x7c8/0x850 kernel/events/core.c:5495 perf_release+0x3b/0x40 kernel/events/core.c:5505 __fput+0x221/0x940 fs/file_table.c:418 task_work_run+0x1d4/0x260 kernel/task_work.c:245 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0x986/0x2530 kernel/exit.c:884 do_group_exit+0x22d/0x2f0 kernel/exit.c:1026 get_signal+0x12a6/0x1390 kernel/signal.c:2903 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f000279de59 RSP: 002b:00007f00035e2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: 0000000000000012 RBX: 00007f0002a25fa0 RCX: 00007f000279de59 RDX: 0000000000000012 RSI: 0000200000000200 RDI: 000000000000000d RBP: 00007f0002833e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0002a26038 R14: 00007f0002a25fa0 R15: 00007ffc1a6ebeb8 Showing all locks held in the system: 2 locks held by kworker/0:0/8: #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2730 #1: ffffc900000d7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc900000d7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2730 1 lock held by khungtaskd/28: #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by getty/5531: #0: ffff88814c9fa0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217 3 locks held by kworker/1:4/5878: #0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2730 #1: ffffc900049bfd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc900049bfd00 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2730 #2: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/u4:54/10922: #0: ffff888017c71538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888017c71538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2730 #1: ffffc9000bad7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc9000bad7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2730 #2: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:286 3 locks held by kworker/u4:57/10925: #0: ffff8880b8f3c298 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559 #1: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #1: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #1: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: do_perf_sw_event kernel/events/core.c:9952 [inline] #1: ffffffff8d131da0 (rcu_read_lock){....}-{1:2}, at: ___perf_sw_event+0x19e/0x730 kernel/events/core.c:9990 #2: ffff8880b8f295d8 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x6cf/0xd60 kernel/time/timer.c:1112 2 locks held by syz.4.2056/11807: 5 locks held by syz.4.2062/11823: 2 locks held by syz.0.2074/11854: 2 locks held by syz.1.2087/11883: #0: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3514 #1: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #1: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 2 locks held by syz.1.2087/11888: #0: ffffffff8d187ee8 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2e/0x140 kernel/trace/trace_event_perf.c:239 #1: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #1: ffffffff8d137778 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004 3 locks held by syz.4.2084/11889: 2 locks held by syz.2.2088/11892: #0: ffffffff8e43a8d0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1074 #1: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: nl80211_pre_doit+0x5e/0x890 net/wireless/nl80211.c:16518 1 lock held by syz.4.2090/11898: #0: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline] #0: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ed/0xf90 net/core/rtnetlink.c:6473 1 lock held by syz.4.2090/11899: #0: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f7/0x2070 drivers/net/tun.c:3124 1 lock held by syz.4.2090/11900: #0: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f7/0x2070 drivers/net/tun.c:3124 1 lock held by syz.4.2090/11903: #0: ffffffff8e3d5b08 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f7/0x2070 drivers/net/tun.c:3124 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf59/0xfa0 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 11889 Comm: syz.4.2084 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212 Code: 00 0f 0b 0f 1f 80 00 00 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d ec 87 05 0d 48 89 de 5b e9 23 a7 57 00 cc cc cc 0f 1e fa 48 8b 04 24 65 48 8b 0d c0 d2 7c 7e 65 8b 15 c1 d2 7c RSP: 0018:ffffc90004efe8c8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888027bfbc00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: dffffc0000000000 R08: ffffffff8e8c6b2f R09: 1ffffffff1d18d65 R10: dffffc0000000000 R11: fffffbfff1d18d66 R12: 00fff00000000000 R13: dffffc0000000000 R14: ffffea00014dcd80 R15: dead000000000100 FS: 00007f7e5af136c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055611e3f7088 CR3: 000000006763f000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] page_fixed_fake_head include/linux/page-flags.h:209 [inline] _compound_head include/linux/page-flags.h:250 [inline] PageSlab include/linux/page-flags.h:501 [inline] __page_table_check_zero+0xea/0x4b0 mm/page_table_check.c:146 prep_new_page mm/page_alloc.c:1589 [inline] get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501 __folio_alloc+0x10/0x20 mm/page_alloc.c:4533 vma_alloc_folio+0x474/0x8f0 mm/mempolicy.c:2240 shmem_alloc_folio+0x1a9/0x2a0 mm/shmem.c:1679 shmem_alloc_and_acct_folio+0x1cb/0x6c0 mm/shmem.c:1704 shmem_get_folio_gfp+0xe1d/0x2b40 mm/shmem.c:2041 shmem_get_folio mm/shmem.c:2164 [inline] shmem_write_begin+0xf2/0x430 mm/shmem.c:2706 generic_perform_write+0x2fe/0x5c0 mm/filemap.c:4036 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:2883 __kernel_write_iter+0x29f/0x6d0 fs/read_write.c:517 dump_emit_page fs/coredump.c:957 [inline] dump_user_range+0x418/0x840 fs/coredump.c:984 elf_core_dump+0x320e/0x37c0 fs/binfmt_elf.c:2184 do_coredump+0x1791/0x24a0 fs/coredump.c:833 get_signal+0x10da/0x1390 kernel/signal.c:2889 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 irqentry_exit_to_user_mode+0x9/0x30 kernel/entry/common.c:315 exc_general_protection+0x168/0x1f0 arch/x86/kernel/traps.c:745 asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:602 RIP: 0033:0x7f7e59f9de61 Code: 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 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f RSP: 002b:0000200000000050 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f7e5a225fa0 RCX: 00007f7e59f9de59 RDX: 00002000000003c0 RSI: 0000200000000050 RDI: 0000000002108000 RBP: 00007f7e5a033e6f R08: 0000200000000440 R09: 0000200000000440 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f7e5a226038 R14: 00007f7e5a225fa0 R15: 00007ffe377cf848