rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5487/1:b..l P7514/1:b..l P5822/1:b..l rcu: (detected by 1, t=10502 jiffies, g=30321, q=488 ncpus=2) task:syz-executor state:R running task stack:19496 pid:5822 tgid:5822 ppid:5816 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 00 c6 c0 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 1a 34 04 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ff a3 c3 09 cc 48 8d 3d d7 c3 07 RSP: 0018:ffffc9000400f598 EFLAGS: 00000282 RAX: 8e6174c25933a900 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 000000005a44979c RSI: ffffffff8db8dbf6 RDI: ffffffff8be09d60 RBP: ffffffff81745df5 R08: ffffffff81745df5 R09: ffffffff8e144f60 R10: ffffc9000400f6f8 R11: ffffffff81ad18d0 R12: 0000000000000002 R13: ffffffff8e144f60 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [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 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2556 [inline] slab_free mm/slub.c:6690 [inline] kfree+0x1c0/0x660 mm/slub.c:6898 __do_replace+0x827/0x980 net/ipv6/netfilter/ip6_tables.c:1107 do_replace net/ipv6/netfilter/ip6_tables.c:1158 [inline] do_ip6t_set_ctl+0xa16/0xce0 net/ipv6/netfilter/ip6_tables.c:1644 nf_setsockopt+0x26f/0x290 net/netfilter/nf_sockopt.c:101 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2337 __sys_setsockopt net/socket.c:2362 [inline] __do_sys_setsockopt net/socket.c:2368 [inline] __se_sys_setsockopt net/socket.c:2365 [inline] __x64_sys_setsockopt+0x13f/0x1b0 net/socket.c:2365 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4d2639163a RSP: 002b:00007ffee382e358 EFLAGS: 00000202 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007ffee382e3e0 RCX: 00007f4d2639163a RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000003 RBP: 0000000000000003 R08: 00000000000003b8 R09: 0079746972756365 R10: 00007f4d265b5d00 R11: 0000000000000202 R12: 00007f4d265b5ca0 R13: 00007ffee382e37c R14: 0000000000000000 R15: 00007f4d265b7e60 task:syz.1.314 state:R running task stack:24664 pid:7514 tgid:7514 ppid:5830 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 00 c6 c0 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 1a 34 04 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ff a3 c3 09 cc 48 8d 3d d7 c3 07 RSP: 0018:ffffc9000e3ff7f8 EFLAGS: 00000282 RAX: 57d69590dbd72b00 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000e913ca6f RSI: ffffffff8db8dbf6 RDI: ffffffff8be09d60 RBP: ffffffff81745df5 R08: ffffffff81745df5 R09: ffffffff8e144f60 R10: ffffc9000e3ff958 R11: ffffffff81ad18d0 R12: 0000000000000002 R13: ffffffff8e144f60 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [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 save_stack+0xf5/0x1f0 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1436 [inline] __free_frozen_pages+0xb99/0xd10 mm/page_alloc.c:2976 vfree+0x25a/0x400 mm/vmalloc.c:3471 do_free_pages sound/core/pcm_memory.c:88 [inline] snd_pcm_lib_free_pages+0x250/0x2e0 sound/core/pcm_memory.c:495 do_hw_free sound/core/pcm_native.c:916 [inline] snd_pcm_release_substream+0x2b7/0x480 sound/core/pcm_native.c:2740 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2401 [inline] snd_pcm_oss_release+0x181/0x250 sound/core/oss/pcm_oss.c:2580 __fput+0x44c/0xa70 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xef/0x4e0 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+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f533b78f749 RSP: 002b:00007ffe4f409ce8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f533b9e7da0 RCX: 00007f533b78f749 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f533b9e7da0 R08: 000000000000203c R09: 000000184f409fdf R10: 00007f533b9e7cb0 R11: 0000000000000246 R12: 000000000003f06c R13: 00007f533b9e6090 R14: ffffffffffffffff R15: 00007ffe4f409e00 task:dhcpcd state:R running task stack:21240 pid:5487 tgid:5487 ppid:5486 task_flags:0x40054c flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x2d8/0x3b0 kernel/locking/lockdep.c:5893 Code: 48 04 11 00 00 00 00 eb b5 e8 64 94 c0 09 f7 c3 00 02 00 00 74 b9 65 48 8b 05 84 02 04 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d b1 95 07 RSP: 0018:ffffc90003547a80 EFLAGS: 00000282 RAX: a6d9d1961065a100 RBX: 0000000000000202 RCX: 0000000000000046 RDX: 0000000000000000 RSI: ffffffff8db8dbf6 RDI: ffffffff8be09d60 RBP: ffff88802de20b08 R08: ffffffff82434cac R09: ffffffff8e144f60 R10: dffffc0000000000 R11: ffffed100602a708 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8e144f60 R15: ffff88802de20000 rcu_lock_release include/linux/rcupdate.h:322 [inline] rcu_read_unlock include/linux/rcupdate.h:881 [inline] mntput_no_expire+0x190/0x1c0 fs/namespace.c:1414 free_fs_struct fs/fs_struct.c:86 [inline] exit_fs+0xed/0x150 fs/fs_struct.c:103 do_exit+0x84e/0x2590 kernel/exit.c:967 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x1285/0x1340 kernel/signal.c:3034 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+0x87/0x4e0 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+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4809091f07 RSP: 002b:00007ffc375d6950 EFLAGS: 00000246 ORIG_RAX: 000000000000000e RAX: 0000000000000000 RBX: 00007ffc375d6968 RCX: 00007f4809091f07 RDX: 0000000000000000 RSI: 00007ffc375d6968 RDI: 0000000000000002 RBP: 0000000000001d65 R08: 00007f4809224b60 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffc375d6aa0 R13: 0000000000000000 R14: 0000000000000000 R15: 000055b7053a5ac0 rcu: rcu_preempt kthread starved for 10411 jiffies! g30321 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:27776 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 __schedule_loop kernel/sched/core.c:6976 [inline] schedule+0x165/0x360 kernel/sched/core.c:6991 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297 kthread+0x389/0x480 kernel/kthread.c:467 ret_from_fork+0x510/0xa50 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 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 e3 3f 29 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07dc0 EFLAGS: 000002c2 RAX: 000000000057196d RBX: ffffffff81977eae RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d9a99b4 RDI: ffffffff8be09d60 RBP: ffffffff8de07eb0 R08: ffff8880b863375b R09: 1ffff110170c66eb R10: dffffc0000000000 R11: ffffed10170c66ec R12: ffffffff8fa2d8f0 R13: 1ffffffff1bd29d0 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125bf7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4d265b5d58 CR3: 00000000741c8000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1be/0x4d0 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:758 start_kernel+0x38b/0x3e0 init/main.c:1209 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147