rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7183/1:b..l P5236/1:b..l rcu: (detected by 0, t=10502 jiffies, g=19437, q=203 ncpus=2) task:udevd state:R running task stack:22832 pid:5236 tgid:5236 ppid:1 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__rcu_read_lock+0x32/0x60 kernel/rcu/tree_plugin.h:416 Code: 1c 25 08 b0 a0 92 48 81 c3 44 04 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 18 ff 03 8b 03 <3d> 00 00 00 40 7d 07 5b c3 cc cc cc cc cc 90 0f 0b 90 eb f3 89 d9 RSP: 0018:ffffc90003057168 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff88807e705e44 RCX: dffffc0000000000 RDX: dffffc0000000000 RSI: ffffffff82379fd5 RDI: ffffc90003057248 RBP: dffffc0000000000 R08: ffffc90003057310 R09: 0000000000000008 R10: ffffc90003057298 R11: ffffffff81ac4b00 R12: 1ffff9200060ae49 R13: ffffc90003057280 R14: ffffc90003057248 R15: ffffc90003057980 rcu_read_lock include/linux/rcupdate.h:839 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x9e/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kfree+0x18e/0x440 mm/slub.c:4894 tomoyo_check_open_permission+0x2c2/0x3b0 security/tomoyo/file.c:786 security_file_open+0xb1/0x270 security/security.c:3144 do_dentry_open+0x384/0x13f0 fs/open.c:942 vfs_open+0x3b/0x340 fs/open.c:1095 do_open fs/namei.c:3887 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4046 do_filp_open+0x1fa/0x410 fs/namei.c:4073 do_sys_openat2+0x121/0x1c0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff1e5d15c3a RSP: 002b:00007fffd0cff1c8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000055a25c924a50 RCX: 00007ff1e5d15c3a RDX: 0000000000090800 RSI: 000055a25c8af510 RDI: 00000000ffffff9c RBP: 000055a25c8af510 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000206 R12: 000055a25c8bb7b0 R13: 00000000000000fd R14: 000055a243a5bbe0 R15: 00007fffd0cff4d0 task:syz.4.196 state:R running task stack:26200 pid:7183 tgid:7176 ppid:5884 task_flags:0x400040 flags:0x20004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:mod_node_state+0xf/0x160 mm/vmstat.c:620 Code: c9 eb 18 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 41 54 53 89 cd 41 89 d4 <41> 89 f7 49 89 fe 48 8d 9f 40 5a 00 00 48 89 d8 48 c1 e8 03 48 b9 RSP: 0018:ffffc90019e871d0 EFLAGS: 00000246 RAX: 1ffffffff3365d80 RBX: ffffea0001d8b080 RCX: 0000000000000000 RDX: ffffffffffffffff RSI: 0000000000000008 RDI: ffff88813fffb400 RBP: 0000000000000000 R08: ffffea0001d8b087 R09: 1ffffd40003b1610 R10: dffffc0000000000 R11: fffff940003b1611 R12: 00000000ffffffff R13: dffffc0000000000 R14: ffffffff99b2ec00 R15: ffffffffffffffff node_stat_mod_folio include/linux/vmstat.h:468 [inline] release_pte_folio+0x186/0x210 mm/khugepaged.c:518 __collapse_huge_page_copy_succeeded mm/khugepaged.c:734 [inline] __collapse_huge_page_copy mm/khugepaged.c:829 [inline] collapse_huge_page mm/khugepaged.c:1231 [inline] hpage_collapse_scan_pmd+0x29c0/0x3c60 mm/khugepaged.c:1436 madvise_collapse+0x3d1/0xa40 mm/khugepaged.c:2813 madvise_vma_behavior+0xec8/0x3af0 mm/madvise.c:1358 madvise_walk_vmas+0x51c/0xa30 mm/madvise.c:1669 madvise_do_behavior+0x38e/0x550 mm/madvise.c:1885 do_madvise+0x1bc/0x270 mm/madvise.c:1978 __do_sys_madvise mm/madvise.c:1987 [inline] __se_sys_madvise mm/madvise.c:1985 [inline] __ia32_sys_madvise+0xa7/0xc0 mm/madvise.c:1985 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf704e539 RSP: 002b:00000000f4fd955c EFLAGS: 00000206 ORIG_RAX: 00000000000000db RAX: ffffffffffffffda RBX: 0000000080000000 RCX: 0000000000600003 RDX: 0000000000000019 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10591 jiffies! g19437 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=15086 rcu: rcu_preempt kthread starved for 10592 jiffies! g19437 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27432 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 7181 Comm: syz.4.196 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x46/0x70 kernel/kcov.c:222 Code: ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 3c 16 00 00 00 74 2c 8b 91 18 16 00 00 83 fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 1c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 RSP: 0018:ffffc90019f170d8 EFLAGS: 00000246 RAX: ffffffff8a226992 RBX: 0000000003000000 RCX: ffff8880336d3c00 RDX: ffffc9000e411000 RSI: 000000000007ffff RDI: 0000000003000000 RBP: ffffc90019f17230 R08: 0000000000000000 R09: ffffffff8a226780 R10: dffffc0000000000 R11: fffff520033e2e0c R12: dffffc0000000000 R13: ffff88802f01c880 R14: 000000000a000000 R15: ffffc90019f176a0 FS: 0000000000000000(0000) GS:ffff888125c15000(0063) knlGS:00000000f53fcb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000f5445da4 CR3: 0000000077a20000 CR4: 00000000003526f0 Call Trace: xfrm_state_lookup_spi_proto net/xfrm/xfrm_state.c:1708 [inline] xfrm_alloc_spi+0x4b2/0xf30 net/xfrm/xfrm_state.c:2589 xfrm_alloc_userspi+0x70b/0xc90 net/xfrm/xfrm_user.c:1873 xfrm_user_rcv_msg+0x7a0/0xab0 net/xfrm/xfrm_user.c:3501 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3523 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82c/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:729 ____sys_sendmsg+0x505/0x830 net/socket.c:2614 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668 __sys_sendmsg+0x164/0x220 net/socket.c:2700 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf704e539 Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f53fc55c EFLAGS: 00000206 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000080000080 RDX: 0000000000004810 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000