INFO: task kworker/u10:3:15541 blocked for more than 143 seconds. Tainted: G U 6.16.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u10:3 state:D stack:27448 pid:15541 tgid:15541 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x2ff/0x4e0 kernel/sched/completion.c:116 __flush_workqueue+0x3e2/0x1230 kernel/workqueue.c:4002 rds_tcp_listen_stop+0x104/0x150 net/rds/tcp_listen.c:351 rds_tcp_kill_sock net/rds/tcp.c:611 [inline] rds_tcp_exit_net+0xcb/0x810 net/rds/tcp.c:634 ops_exit_list net/core/net_namespace.c:200 [inline] ops_undo_list+0x2eb/0xab0 net/core/net_namespace.c:253 cleanup_net+0x408/0x890 net/core/net_namespace.c:686 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e5c47c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c47c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c47c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6770 1 lock held by udevd/5200: #0: ffff88801c6ff188 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_dop_revalidate+0xa5/0x740 fs/kernfs/dir.c:1180 2 locks held by getty/5597: #0: ffff88803206e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 2 locks held by sshd-session/5818: 2 locks held by syz-executor/5829: 1 lock held by syz-executor/5836: #0: ffffffff8e5cfdb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 3 locks held by kworker/u10:3/15541: #0: ffff88801c6fe148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90002fa7d10 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90337c90 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x890 net/core/net_namespace.c:662 1 lock held by syz.2.1709/15860: #0: ffffffff90337c90 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:570 1 lock held by syz-executor/16127: #0: ffffffff8e5cfdb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 1 lock held by syz.3.1918/17108: #0: ffffffff90337c90 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:570 3 locks held by syz.1.2169/18627: #0: ffff88803c8451c0 (&tty->legacy_mutex){+.+.}-{4:4}, at: __tty_hangup.part.0+0xae/0x890 drivers/tty/tty_io.c:581 #1: ffff88803c8450a0 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:289 [inline] #1: ffff88803c8450a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock+0x65/0xb0 drivers/tty/tty_ldisc.c:313 #2: ffffffff9034dce8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff9034dce8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2143 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U 6.16.0-rc4-syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:470 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5824 Comm: syz-executor Tainted: G U 6.16.0-rc4-syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:58 [inline] RIP: 0010:stack_access_ok+0x6e/0x200 arch/x86/kernel/unwind_orc.c:393 Code: 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 52 01 00 00 48 89 da 48 8b 4b 10 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 0b 01 00 00 8b 13 85 d2 74 23 RSP: 0018:ffffc90003fbf668 EFLAGS: 00000a02 RAX: dffffc0000000000 RBX: ffffc90003fbf718 RCX: ffffc90003fc0000 RDX: 1ffff920007f7ee3 RSI: ffffc90003fbff10 RDI: ffffc90003fbf718 RBP: ffffc90003fbff10 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 000000000000a50a R12: 0000000000000008 R13: ffffc90003fbf728 R14: ffffc90003fbf720 R15: ffffc90003fb8000 FS: 0000000000000000(0000) GS:ffff88812485f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b302d1ff8 CR3: 0000000034e48000 CR4: 00000000003526f0 Call Trace: deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0x15c5/0x20a0 arch/x86/kernel/unwind_orc.c:648 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706 vfree+0x1fd/0xb50 mm/vmalloc.c:3426 kcov_put kernel/kcov.c:439 [inline] kcov_put kernel/kcov.c:435 [inline] kcov_close+0x34/0x60 kernel/kcov.c:535 __fput+0x402/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x86c/0x2bd0 kernel/exit.c:964 do_group_exit+0xd3/0x2a0 kernel/exit.c:1105 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x490 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3585984b53 Code: Unable to access opcode bytes at 0x7f3585984b29. RSP: 002b:00007ffcbf79c4f8 EFLAGS: 00000202 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 00000000000016cc RCX: 00007f3585984b53 RDX: 0000000040000000 RSI: 00007ffcbf79c50c RDI: 00000000ffffffff RBP: 00007ffcbf79c50c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008 R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000 vkms_vblank_simulate: vblank timer overrun