rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5854/1:b..l P5855/1:b..l P5213/1:b..l rcu: (detected by 0, t=10502 jiffies, g=11697, q=209 ncpus=2) task:udevd state:R running task stack:24744 pid:5213 tgid:5213 ppid:1 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x244/0x3e0 arch/x86/include/asm/irqflags.h:-1 Code: 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 0f 85 c3 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 48 8b 03 <48> 3b 44 24 28 0f 85 82 01 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90003027658 EFLAGS: 00000206 RAX: 4f56dd2823592f00 RBX: ffffffff93687020 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8e4fc666 RDI: ffffffff8ca1b140 RBP: ffff88807d824718 R08: ffffffff82504fdb R09: 1ffffffff20bf9ee R10: dffffc0000000000 R11: fffffbfff20bf9ef R12: 0000000000000001 R13: ffff88807d823c00 R14: 0000000000000206 R15: ffffffff8ed3dfe0 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] prepend_path+0x959/0xd10 fs/d_path.c:182 d_absolute_path+0x17b/0x310 fs/d_path.c:234 tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline] tomoyo_realpath_from_path+0x2b4/0x5e0 security/tomoyo/realpath.c:271 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x2be/0x640 security/tomoyo/file.c:822 security_inode_getattr+0x130/0x330 security/security.c:2377 vfs_getattr fs/stat.c:243 [inline] vfs_statx_path+0x23/0x2b0 fs/stat.c:283 vfs_statx+0x13a/0x200 fs/stat.c:349 vfs_fstatat+0xdc/0x150 fs/stat.c:368 __do_sys_newfstatat fs/stat.c:532 [inline] __se_sys_newfstatat fs/stat.c:526 [inline] __x64_sys_newfstatat+0x11f/0x1a0 fs/stat.c:526 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f87ce1625f4 RSP: 002b:00007ffc24bd6d48 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000055c6756c16c0 RCX: 00007f87ce1625f4 RDX: 00007ffc24bd6d58 RSI: 000055c6756af7ed RDI: 00000000ffffff9c RBP: 000055c67663e448 R08: 000000000dbca4a4 R09: 7fffffffffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000000 R15: 000055c6756b5dca task:syz-executor state:R running task stack:18808 pid:5855 tgid:5855 ppid:5838 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_is_watching+0x67/0xb0 kernel/rcu/tree.c:737 Code: 89 f7 e8 6c c6 84 00 48 c7 c3 58 9b 69 93 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 22 8b 03 65 ff 0d 79 ba bf 11 <74> 10 83 e0 04 c1 e8 02 5b 41 5e 41 5f c3 cc cc cc cc e8 f2 d1 81 RSP: 0018:ffffc900041bf7a8 EFLAGS: 00000286 RAX: 0000000000026134 RBX: ffff8880b8632b58 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff8ca1b120 RDI: ffffffff8ca1b0e0 RBP: ffffffff93687020 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc900041bf970 R11: ffffffff81aee9b0 R12: 0000000000000000 R13: 0000000000000002 R14: ffffffff8e797c10 R15: dffffc0000000000 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x5e/0x2f0 kernel/locking/lockdep.c:5829 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd5/0x23b0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 save_stack+0xfc/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x1e0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0xde8/0x10a0 mm/page_alloc.c:2680 discard_slab mm/slub.c:2720 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3189 put_cpu_partial+0x17e/0x250 mm/slub.c:3264 __slab_free+0x294/0x390 mm/slub.c:4516 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4151 [inline] slab_alloc_node mm/slub.c:4200 [inline] kmem_cache_alloc_noprof+0x1e1/0x390 mm/slub.c:4207 getname_flags+0xb6/0x530 fs/namei.c:146 getname include/linux/fs.h:2852 [inline] __do_sys_unlink fs/namei.c:4654 [inline] __se_sys_unlink fs/namei.c:4652 [inline] __x64_sys_unlink+0x3a/0x50 fs/namei.c:4652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb50558c717 RSP: 002b:00007fb5058cecb8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb50558c717 RDX: 00007fb5058cece0 RSI: 00007fb5058ced70 RDI: 00007fb5058ced70 RBP: 00007fb5058ced70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000206 R12: 00007fb5058cfe00 R13: 00007fb50560e08c R14: 000000000001aeb4 R15: 00007fb5058cfe40 task:syz-executor state:R running task stack:20648 pid:5854 tgid:5854 ppid:5836 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x167/0x2f0 arch/x86/include/asm/irqflags.h:-1 Code: c7 44 24 10 00 00 00 00 9c 8f 44 24 10 f7 44 24 10 00 02 00 00 0f 85 fd 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 48 8b 45 00 <48> 3b 44 24 38 0f 85 72 01 00 00 48 83 c4 40 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000413efc8 EFLAGS: 00000206 RAX: 9ec5f729df726a00 RBX: ffffffff8ed3dfe0 RCX: 9ec5f729df726a00 RDX: 0000000000000000 RSI: ffffffff8e4fc666 RDI: ffffffff8ca1b140 RBP: ffffffff93687020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000246 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd5/0x23b0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 save_stack+0xfc/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x1e0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0xde8/0x10a0 mm/page_alloc.c:2680 discard_slab mm/slub.c:2720 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3189 put_cpu_partial+0x17e/0x250 mm/slub.c:3264 __slab_free+0x294/0x390 mm/slub.c:4516 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4151 [inline] slab_alloc_node mm/slub.c:4200 [inline] __do_kmalloc_node mm/slub.c:4330 [inline] __kmalloc_node_noprof+0x23f/0x4d0 mm/slub.c:4337 kmalloc_array_node_noprof include/linux/slab.h:1020 [inline] alloc_slab_obj_exts+0x3a/0xa0 mm/slub.c:1987 __memcg_slab_post_alloc_hook+0x31c/0x7e0 mm/memcontrol.c:3075 memcg_slab_post_alloc_hook mm/slub.c:2188 [inline] slab_post_alloc_hook mm/slub.c:4161 [inline] slab_alloc_node mm/slub.c:4200 [inline] kmem_cache_alloc_noprof+0x28f/0x390 mm/slub.c:4207 vm_area_dup+0x2b/0x5b0 kernel/fork.c:488 dup_mmap kernel/fork.c:672 [inline] dup_mm kernel/fork.c:1734 [inline] copy_mm+0xc70/0x22c0 kernel/fork.c:1786 copy_process+0x17de/0x3d10 kernel/fork.c:2429 kernel_clone+0x242/0x930 kernel/fork.c:2844 __do_sys_clone kernel/fork.c:2987 [inline] __se_sys_clone kernel/fork.c:2971 [inline] __x64_sys_clone+0x268/0x2e0 kernel/fork.c:2971 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3f27f839d3 RSP: 002b:00007f3f282cfca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3f27f839d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555857cf7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000058 R14: 0000000000019941 R15: 00007f3f282cfe40 rcu: rcu_preempt kthread starved for 10172 jiffies! g11697 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:26976 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.14.0-syzkaller-12966-ga2cc6ff5ec8f #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:unwind_next_frame+0x8f2/0x23b0 arch/x86/kernel/unwind_orc.c:521 Code: 49 8d 5c 24 40 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 0d 78 bf 00 48 8b 03 48 89 44 24 08 48 8d 5d 01 48 89 e8 <48> c1 e8 03 42 0f b6 04 28 84 c0 0f 85 d2 16 00 00 48 89 d8 48 c1 RSP: 0018:ffffc90000a07fa8 EFLAGS: 00000246 RAX: ffffffff90eba972 RBX: ffffffff90eba973 RCX: ffffffff90738710 RDX: ffffffff90eba972 RSI: ffffffff8ca1b120 RDI: ffffffff8ca1b0e0 RBP: ffffffff90eba972 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90000a08080 R13: dffffc0000000000 R14: ffffc90000a080b8 R15: ffffffff90eba976 FS: 0000000000000000(0000) GS:ffff888125099000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055557bd295c8 CR3: 000000000eb38000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2389 [inline] slab_free mm/slub.c:4646 [inline] kmem_cache_free+0x197/0x410 mm/slub.c:4748 vcan_tx+0x5de/0xbd0 drivers/net/can/vcan.c:113 __netdev_start_xmit include/linux/netdevice.h:5201 [inline] netdev_start_xmit include/linux/netdevice.h:5210 [inline] xmit_one net/core/dev.c:3780 [inline] dev_hard_start_xmit+0x2d4/0x840 net/core/dev.c:3796 __dev_queue_xmit+0x1b80/0x3f60 net/core/dev.c:4633 dev_queue_xmit include/linux/netdevice.h:3350 [inline] can_send+0xa05/0xe60 net/can/af_can.c:279 bcm_can_tx+0x5ed/0x9b0 net/can/bcm.c:314 bcm_tx_timeout_handler+0x1f0/0x660 net/can/bcm.c:-1 __run_hrtimer kernel/time/hrtimer.c:1791 [inline] __hrtimer_run_queues+0x5a6/0xd40 kernel/time/hrtimer.c:1855 hrtimer_run_softirq+0x19a/0x2c0 kernel/time/hrtimer.c:1872 handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xfb/0x220 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 01 18 00 f3 0f 1e fa fb f4 cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197dc0 EFLAGS: 000002c2 RAX: cea5d6e8aab2b000 RBX: ffffffff8197afbe RCX: ffffffff8c30393c RDX: 0000000000000001 RSI: ffffffff8e69b738 RDI: ffffffff8ca1b140 RBP: ffffc90000197f20 R08: ffff8880b8732b5b R09: 1ffff110170e656b R10: dffffc0000000000 R11: ffffed10170e656c R12: 1ffff92000032fd2 R13: 1ffff11003adab40 R14: 0000000000000001 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x22e/0x5d0 kernel/sched/idle.c:325 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423 start_secondary+0xfe/0x100 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147