rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=0c1c/1/0x4000000000000000 softirq=52051/52051 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5201/1:b..l P10090/1:b..l P63/1:b..l rcu: (detected by 1, t=10506 jiffies, g=57661, q=415 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5882 Comm: udevd Not tainted 6.14.0-rc1-next-20250207-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:raw_atomic_try_cmpxchg_acquire include/linux/atomic/atomic-arch-fallback.h:2170 [inline] RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1302 [inline] RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] RIP: 0010:do_raw_spin_lock+0x16f/0x370 kernel/locking/spinlock_debug.c:116 Code: be 04 00 00 00 e8 e1 18 8a 00 41 0f b6 44 1d 00 84 c0 48 89 da 0f 85 8d 01 00 00 8b 44 24 60 b9 01 00 00 00 f0 41 0f b1 0c 24 <0f> 85 df 00 00 00 65 8b 1d c0 87 67 7e 41 0f b6 04 17 84 c0 0f 85 RSP: 0018:ffffc90000007bc0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc90000007c20 RBP: ffffc90000007c90 R08: 0000000000000003 R09: fffff52000000f84 R10: dffffc0000000000 R11: fffff52000000f84 R12: ffff8880b862c500 R13: 1ffff92000000f84 R14: ffffc90000007c20 R15: 1ffff110170c58a1 FS: 00007fbbeb310c80(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2e4c7a7bac CR3: 0000000012234000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:120 [inline] _raw_spin_lock_irq+0xdf/0x120 kernel/locking/spinlock.c:170 __run_hrtimer kernel/time/hrtimer.c:1805 [inline] __hrtimer_run_queues+0x670/0xd30 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_is_watching+0x70/0xb0 kernel/rcu/tree.c:718 Code: c3 98 79 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 22 8b 03 65 ff 0d 41 90 5e 7e 74 10 83 e0 04 c1 e8 02 5b <41> 5e 41 5f c3 cc cc cc cc e8 72 f1 84 ff eb e9 89 d9 80 e1 07 80 RSP: 0018:ffffc900043ef670 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 1ffff9200087deec RCX: ffff88805ffdda00 RDX: dffffc0000000000 RSI: ffffffff8c60ca00 RDI: ffffffff8c60c9c0 RBP: ffffc900043ef798 R08: ffffffff9430b847 R09: 1ffffffff2861708 R10: dffffc0000000000 R11: fffffbfff2861709 R12: ffffc900043ef760 R13: dffffc0000000000 R14: ffffffff8e31fb50 R15: dffffc0000000000 rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1164 [inline] unwind_next_frame+0xe7/0x2380 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xaa/0xc0 mm/kasan/generic.c:548 __call_rcu_common kernel/rcu/tree.c:3060 [inline] call_rcu+0x168/0xac0 kernel/rcu/tree.c:3167 destroy_inode fs/inode.c:391 [inline] evict+0x836/0x9a0 fs/inode.c:827 do_unlinkat+0x512/0x830 fs/namei.c:4591 __do_sys_unlink fs/namei.c:4632 [inline] __se_sys_unlink fs/namei.c:4630 [inline] __x64_sys_unlink+0x47/0x50 fs/namei.c:4630 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbbeaf17da7 Code: f0 ff ff 73 01 c3 48 8b 0d 7e 90 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 90 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe19eba4f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 000055634fc6f120 RCX: 00007fbbeaf17da7 RDX: 00007ffe19eba51c RSI: 000055634fc534cd RDI: 00007ffe19eba508 RBP: 00005563523c6ea0 R08: 0000000000000000 R09: 00007ffe19eb9e78 R10: 0000000000000010 R11: 0000000000000202 R12: 0000000000000ab6 R13: 00007ffe19eba508 R14: 0000000003938700 R15: 000055634fc6f160 task:kworker/u8:4 state:R running task stack:18896 pid:63 tgid:63 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5377 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6764 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7086 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+0x264/0x550 kernel/locking/lockdep.c:5855 Code: 2b 00 74 08 4c 89 f7 e8 ca 7e 8b 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc9000214f7c0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92000429f04 RCX: ffff88801c76e4e8 RDX: dffffc0000000000 RSI: ffffffff8c0abb80 RDI: ffffffff8c60ca20 RBP: ffffc9000214f908 R08: ffffffff9430b847 R09: 1ffffffff2861708 R10: dffffc0000000000 R11: fffffbfff2861709 R12: 1ffff92000429f00 R13: dffffc0000000000 R14: ffffc9000214f820 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:754 [inline] batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:825 [inline] batadv_iv_ogm_schedule+0x43f/0x10a0 net/batman-adv/bat_iv_ogm.c:868 batadv_iv_send_outstanding_bat_ogm_packet+0x6fe/0x810 net/batman-adv/bat_iv_ogm.c:1712 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 task:syz-executor state:R running task stack:12336 pid:10090 tgid:10090 ppid:10076 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5377 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6764 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6943 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6967 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1203 [inline] copy_pmd_range+0x70b1/0x7a80 mm/memory.c:1264 copy_pud_range mm/memory.c:1301 [inline] copy_p4d_range mm/memory.c:1325 [inline] copy_page_range+0x99f/0xe90 mm/memory.c:1423 dup_mmap kernel/fork.c:748 [inline] dup_mm kernel/fork.c:1711 [inline] copy_mm+0x1269/0x2160 kernel/fork.c:1763 copy_process+0x1845/0x3d50 kernel/fork.c:2414 kernel_clone+0x226/0x8e0 kernel/fork.c:2826 __do_sys_clone kernel/fork.c:2969 [inline] __se_sys_clone kernel/fork.c:2953 [inline] __x64_sys_clone+0x267/0x2e0 kernel/fork.c:2953 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3243183653 RSP: 002b:00007ffc92525f58 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3243183653 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055555b6417d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000000aee70 R15: 00007ffc925260f0 task:udevd state:R running task stack:20736 pid:5201 tgid:5201 ppid:1 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5377 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6764 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6943 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6967 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x130/0x140 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock+0x18c/0x1e0 kernel/sched/wait.c:108 sock_def_readable+0x20f/0x5a0 net/core/sock.c:3476 __netlink_sendskb net/netlink/af_netlink.c:1268 [inline] netlink_sendskb+0x9e/0x140 net/netlink/af_netlink.c:1274 netlink_unicast+0x39d/0x990 net/netlink/af_netlink.c:1363 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:733 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2573 ___sys_sendmsg net/socket.c:2627 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2659 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbbeaf24a4b RSP: 002b:00007ffe19ebaa98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00005563523999e0 RCX: 00007fbbeaf24a4b RDX: 0000000000000000 RSI: 00007ffe19ebaaa8 RDI: 0000000000000004 RBP: 00005563523bf650 R08: 0000000000000001 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000000b4 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g57661 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=51745 rcu: rcu_preempt kthread starved for 10506 jiffies! g57661 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:26104 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5377 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6841 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6856 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244