INFO: task kworker/u10:5:10891 blocked for more than 143 seconds. Tainted: G U 6.15.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u10:5 state:D stack:26952 pid:10891 tgid:10891 ppid:2 task_flags:0x4208160 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:116 __flush_workqueue+0x3e2/0x1230 kernel/workqueue.c:4000 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+0xb0/0x180 net/core/net_namespace.c:172 cleanup_net+0x5c1/0xb30 net/core/net_namespace.c:654 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 2 locks held by ksoftirqd/1/23: 1 lock held by khungtaskd/31: #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764 2 locks held by getty/5589: #0: ffff88814d7750a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900030062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 3 locks held by kworker/u10:5/10891: #0: ffff88801c2f6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90017f57d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90114550 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xc9/0xb30 net/core/net_namespace.c:608 1 lock held by syz.0.1371/11721: #0: ffffffff90114550 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:514 1 lock held by syz.2.1446/12069: #0: ffffffff90114550 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:514 1 lock held by syz.5.1690/13209: #0: ffffffff90114550 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:514 2 locks held by syz.4.1702/13265: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U 6.15.0-rc7-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:274 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:437 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153 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: 13265 Comm: syz.4.1702 Tainted: G U 6.15.0-rc7-syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0033:0x7f5d64267db0 Code: 66 2e 0f 1f 84 00 00 00 00 00 48 8b 70 f8 48 83 e8 08 48 39 f2 72 f3 48 39 c3 73 3e 48 89 33 48 83 c3 08 48 8b 70 f8 48 89 08 <48> 8b 0b 49 8b 14 24 eb bf 48 39 f2 72 97 48 39 f0 73 46 49 89 34 RSP: 002b:00007ffef3429ff0 EFLAGS: 00000212 RAX: 00007f5d63b60e40 RBX: 00007f5d63b44b10 RCX: ffffffff8207c5d8 RDX: ffffffff820797fb RSI: ffffffff82062203 RDI: 00007f5d63b7eca8 RBP: 00007f5d63b0d208 R08: 00007f5d63b45f50 R09: 00007f5d645a2000 R10: 00007f5d639ff008 R11: 0000000000000017 R12: 00007f5d63b0d200 R13: 000000000000001d R14: 00007ffef342a148 R15: 00007f5d639ff008 FS: 0000555585f22500 GS: 0000000000000000