rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5834/1:b..l P5494/1:b..l rcu: (detected by 0, t=10502 jiffies, g=8337, q=50 ncpus=2) task:dhcpcd state:R running task stack:21208 pid:5494 tgid:5494 ppid:5493 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:141 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x65/0x2c0 mm/kasan/generic.c:200 Code: 00 00 00 00 00 00 00 ff f3 0f 1e fa 4c 39 cf 0f 82 58 02 00 00 49 89 ff 49 c1 ef 03 49 ba 00 00 00 00 00 fc ff df 4f 8d 1c 17 <49> ff c8 4d 89 c1 49 c1 e9 03 48 bb 01 00 00 00 00 fc ff df 4d 8d RSP: 0018:ffffc90003bcf2a0 EFLAGS: 00000a02 RAX: ffffc90003bcf701 RBX: 0000000000000010 RCX: ffffffff81747d8e RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90003bcf418 RBP: 0000000000000000 R08: ffffc90003bcf428 R09: ffff800000000000 R10: dffffc0000000000 R11: fffff52000779e83 R12: ffffc90003bcf418 R13: 1ffff92000779e7b R14: ffffc90003bcf418 R15: 1ffff92000779e83 __asan_memset+0x22/0x50 mm/kasan/shadow.c:84 unwind_next_frame+0xeae/0x23d0 arch/x86/kernel/unwind_orc.c:607 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:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5267 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5274 vm_area_dup+0x2b/0x680 mm/vma_init.c:123 dup_mmap+0x870/0x1b80 mm/mmap.c:1773 dup_mm kernel/fork.c:1533 [inline] copy_mm+0x14f/0x770 kernel/fork.c:1585 copy_process+0x165d/0x3950 kernel/fork.c:2225 kernel_clone+0x21e/0x820 kernel/fork.c:2655 __do_sys_clone kernel/fork.c:2796 [inline] __se_sys_clone kernel/fork.c:2780 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2780 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb0c7fda636 RSP: 002b:00007ffe2837d8d0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe2837d8d8 RCX: 00007fb0c7fda636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe2839de20 R08: 0000000000000000 R09: 0000000000000001 R10: 00007fb0c7f06a10 R11: 0000000000000246 R12: 00007ffe2837da10 R13: 0000000000000000 R14: 0000000000000000 R15: 00005567ac0a0ac0 task:syz-executor403 state:R running task stack:22392 pid:5834 tgid:5834 ppid:5831 task_flags:0x400140 flags:0x00080800 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 44 91 25 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000446f1b8 EFLAGS: 00000206 RAX: 72ace07b704fda00 RBX: 0000000000000000 RCX: 72ace07b704fda00 RDX: 000000000edb2309 RSI: ffffffff8dc93c7b RDI: ffffffff8be247e0 RBP: ffffffff81746f85 R08: ffffffff81746f85 R09: ffffffff8e33f2e0 R10: ffffc9000446f378 R11: ffffffff81addd50 R12: 0000000000000002 R13: ffffffff8e33f2e0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 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:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5267 [inline] kmem_cache_alloc_node_noprof+0x43c/0x720 mm/slub.c:5319 __alloc_skb+0x255/0x430 net/core/skbuff.c:679 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] netlink_ack+0x146/0xa50 net/netlink/af_netlink.c:2487 netlink_rcv_skb+0x28c/0x470 net/netlink/af_netlink.c:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737 __sock_sendmsg net/socket.c:752 [inline] __sys_sendto+0x3ce/0x540 net/socket.c:2221 __do_sys_sendto net/socket.c:2228 [inline] __se_sys_sendto net/socket.c:2224 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2224 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbcd4e8ddec RSP: 002b:00007ffebd2716b0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fbcd4e8ddec RDX: 0000000000000024 RSI: 00007fbcd4f10410 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffebd2716f4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 00007fbcd4f10410 rcu: rcu_preempt kthread starved for 10588 jiffies! g8337 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:27976 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 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+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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: 5854 Comm: syz-executor403 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:clockevents_program_min_delta+0x1b0/0x350 kernel/time/clockevents.c:248 Code: 48 d3 ed 48 8b 44 24 30 42 80 3c 38 00 74 0a 48 8b 7c 24 20 e8 11 d0 75 00 48 8b 34 24 4c 8b 5e 08 48 89 ef 2e e8 58 70 4d 1e <89> c5 31 ff 89 c6 e8 b5 2b 0f 00 85 ed 0f 84 34 01 00 00 bf 01 00 RSP: 0018:ffffc9000456fa38 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8880b8723e40 RCX: 0000000000000838 RDX: 0000000000000000 RSI: 000000000000003e RDI: 0000000000000838 RBP: 000000000000003e R08: ffffffff81afa4e5 R09: ffffffff99d3d508 R10: 0000000000000003 R11: ffffffff8171bb10 R12: ffff8880b8723e80 R13: ffff8880b8723e78 R14: 0000000000000020 R15: dffffc0000000000 FS: 000055555b45a480(0000) GS:ffff888125adc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 000000001fb18000 CR4: 00000000003526f0 Call Trace: hrtimer_start_range_ns+0xd8a/0x1080 kernel/time/hrtimer.c:1323 __posixtimer_deliver_signal kernel/time/posix-timers.c:321 [inline] posixtimer_deliver_signal+0x1cf/0x410 kernel/time/posix-timers.c:347 dequeue_signal+0x24a/0x370 kernel/signal.c:660 get_signal+0x55e/0x1340 kernel/signal.c:2914 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbcd4e8c229 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 1f 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffebd271568 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fbcd4e8c229 RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000003 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbcd4edc27c R13: 0000000000000003 R14: 00007ffebd2715b0 R15: 0000000000000000