rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8342/1:b..l P9673/1:b..l P9725/1:b..l rcu: (detected by 0, t=10503 jiffies, g=49957, q=216 ncpus=2) task:udevd state:R running task stack:25616 pid:9725 ppid:4468 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0xee1/0x59f0 kernel/sched/core.c:6710 preempt_schedule_irq+0x52/0x90 kernel/sched/core.c:7022 irqentry_exit+0x35/0x80 kernel/entry/common.c:433 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:650 RIP: 0010:link_path_walk.part.0.constprop.0+0x500/0xce0 fs/namei.c:2299 Code: 00 49 8d 7f 50 4d 89 77 18 48 be 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 0f b6 04 30 84 c0 74 08 3c 03 0f 8e 56 06 00 00 <8b> 44 24 08 49 01 ee 48 bf 00 00 00 00 00 fc ff df 4c 89 f2 83 e2 RSP: 0018:ffffc900056efb08 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00000003b0e02c30 RCX: 0000000000000000 RDX: ffff88807364a200 RSI: dffffc0000000000 RDI: ffffc900056efcd0 RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000080000000 R13: 766564752f6e7572 R14: ffff8880675c66a1 R15: ffffc900056efc80 link_path_walk fs/namei.c:2250 [inline] path_parentat+0xaa/0x1b0 fs/namei.c:2526 __filename_parentat+0x1f2/0x640 fs/namei.c:2550 filename_parentat fs/namei.c:2568 [inline] do_unlinkat+0x109/0x6d0 fs/namei.c:4368 __do_sys_unlink fs/namei.c:4443 [inline] __se_sys_unlink fs/namei.c:4441 [inline] __x64_sys_unlink+0xc8/0x110 fs/namei.c:4441 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f1a5ef17da7 RSP: 002b:00007ffe019e2e58 EFLAGS: 00000202 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 000055a373ca0120 RCX: 00007f1a5ef17da7 RDX: 00007ffe019e2e7c RSI: 000055a373c844cd RDI: 00007ffe019e2e68 RBP: 000055a373fa3850 R08: 0000000000000000 R09: 00007ffe019e27d8 R10: 0000000000000007 R11: 0000000000000202 R12: 0000000000000929 R13: 00007ffe019e2e68 R14: 0000000003938700 R15: 000055a373ca0160 task:udevd state:R running task stack:26752 pid:9673 ppid:4468 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0xee1/0x59f0 kernel/sched/core.c:6710 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6879 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x5d/0x70 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock+0xe3/0x140 kernel/sched/wait.c:140 sock_def_readable+0x158/0x760 net/core/sock.c:3322 unix_dgram_sendmsg+0x1133/0x1c30 net/unix/af_unix.c:2093 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg+0xd9/0x180 net/socket.c:748 sock_write_iter+0x29b/0x3d0 net/socket.c:1129 call_write_iter include/linux/fs.h:1877 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x650/0xe40 fs/read_write.c:584 ksys_write+0x1f0/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f1a5ef16bf2 RSP: 002b:00007ffe019e32d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1a5ef16bf2 RDX: 0000000000000000 RSI: 00007ffe019e332f RDI: 000000000000000a RBP: 00007ffe019e332f R08: 0000000000000001 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 000000000000000a R13: 00007f1a5f337ae0 R14: 0000000000000000 R15: 000055a373f632c0 task:kworker/u4:9 state:R running task stack:27056 pid:8342 ppid:2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0xee1/0x59f0 kernel/sched/core.c:6710 preempt_schedule_irq+0x52/0x90 kernel/sched/core.c:7022 irqentry_exit+0x35/0x80 kernel/entry/common.c:433 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5729 Code: c1 05 75 57 9c 7e 83 f8 01 0f 85 b0 02 00 00 9c 58 f6 c4 02 0f 85 9b 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc900061d7a08 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff92000c3af43 RCX: 0000000000000001 RDX: 1ffff1100f1f2160 RSI: ffffffff8a6c74c0 RDI: ffffffff8ac7edc0 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff23087d0 R10: ffffffff91843e87 R11: 1ffffffff1935df9 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8c9a41c0 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:303 [inline] rcu_read_lock include/linux/rcupdate.h:749 [inline] inet_twsk_purge+0x139/0x920 net/ipv4/inet_timewait_sock.c:292 ops_exit_list+0x125/0x170 net/core/net_namespace.c:175 cleanup_net+0x505/0xb20 net/core/net_namespace.c:614 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600 worker_thread+0x687/0x1110 kernel/workqueue.c:2751 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 rcu: rcu_preempt kthread starved for 10576 jiffies! g49957 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:28160 pid:15 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0xee1/0x59f0 kernel/sched/core.c:6710 schedule+0xe7/0x1b0 kernel/sched/core.c:6786 schedule_timeout+0x157/0x2c0 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x1ec/0xa50 kernel/rcu/tree.c:1609 rcu_gp_kthread+0x249/0x380 kernel/rcu/tree.c:1808 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 12072 Comm: syz-executor.1 Not tainted 6.5.0-rc5-syzkaller-00296-gf8de32cc060b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 RIP: 0010:__might_fault+0x55/0x190 mm/memory.c:5854 Code: ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 12 01 00 00 45 8b a4 24 6c 17 00 00 <31> ff 44 89 e6 e8 e1 47 c2 ff 45 85 e4 74 09 5b 5d 41 5c e9 63 4c RSP: 0018:ffffc9000569fca0 EFLAGS: 00000246 RAX: 0000000000000007 RBX: ffffffff8ac7a9e0 RCX: ffffc9000c59a000 RDX: 0000000000000000 RSI: ffffffff81c2d40b RDI: ffff88802117382c RBP: 000000000000000e R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff8eaaeb97 R11: 0000000000000000 R12: 0000000000000000 R13: ffffc9000569fd18 R14: ffff8880211720c0 R15: 0000000000000000 FS: 00007f692e9dd6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e821000 CR3: 0000000028d67000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: _copy_from_user+0x2b/0xf0 lib/usercopy.c:14 copy_from_user include/linux/uaccess.h:183 [inline] restore_sigcontext+0xba/0x630 arch/x86/kernel/signal_64.c:59 __do_sys_rt_sigreturn+0xff/0x1a0 arch/x86/kernel/signal_64.c:260 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f692fe3ff49 Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25 RSP: 002b:00007f692e9dcbc0 EFLAGS: 00000202 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007f692ff9c058 RCX: 00007f692fe3ff49 RDX: 00007f692e9dcbc0 RSI: 00007f692e9dccf0 RDI: 0000000000000021 RBP: 00007f692ff9c050 R08: 00007f692e9dd6c0 R09: 00007f692e9dd6c0 R10: 0000000000000000 R11: 0000000000000202 R12: 00007f692ff9c05c R13: 000000000000006e R14: 00007ffdfe3d06c0 R15: 00007ffdfe3d07a8