rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13810/1:b..l P13285/1:b..l rcu: (detected by 1, t=10503 jiffies, g=71209, q=44 ncpus=2) task:kworker/u4:18 state:R running task stack:26344 pid:13285 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:kasan_check_range+0x1c3/0x290 mm/kasan/generic.c:187 Code: 24 07 4d 85 e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 0e 41 80 3b 00 75 6b 49 ff c3 49 ff cc 75 f2 5b 41 5c 41 5d 41 5e 41 5f 5d 45 84 ff 0f 85 91 00 00 00 41 f7 c7 00 ff 00 00 0f 85 89 00 00 RSP: 0018:ffffc9000bdb7a38 EFLAGS: 00000256 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81680367 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e8ae5e8 RBP: ffffc9000bdb7b48 R08: ffffffff8e8ae5ef R09: 1ffffffff1d15cbd R10: dffffc0000000000 R11: fffffbfff1d15cbe R12: 1ffff920017b6f54 R13: ffffffff8d131da0 R14: 0000000000000000 R15: dffffc0000000000 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] cpumask_test_cpu include/linux/cpumask.h:504 [inline] cpu_online include/linux/cpumask.h:1082 [inline] trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xb7/0x420 kernel/locking/lockdep.c:5725 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xef/0x600 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 task:syz.1.2434 state:R running task stack:26120 pid:13810 ppid:5775 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:__rcu_read_lock+0x2f/0x60 kernel/rcu/tree_plugin.h:404 Code: 65 48 8b 1d f3 37 92 7e 48 81 c3 3c 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 11 ff 03 <8b> 03 3d 00 00 00 40 7d 02 5b c3 0f 0b eb fa 89 d9 80 e1 07 80 c1 RSP: 0018:ffffc9000b61f610 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff88801b2fde3c RCX: dffffc0000000000 RDX: ffff88801b2fda00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000b61f730 R08: ffff88801b2fda07 R09: 1ffff1100365fb40 R10: dffffc0000000000 R11: ffffed100365fb41 R12: ffff88807b6b7800 R13: 1ffff920016c3ed0 R14: ffff888077fdd140 R15: dffffc0000000000 rcu_read_lock include/linux/rcupdate.h:784 [inline] sk_filter_trim_cap+0x183/0x8e0 net/core/filter.c:148 sk_filter include/linux/filter.h:888 [inline] unix_dgram_sendmsg+0x948/0x16e0 net/unix/af_unix.c:2037 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x61b/0x980 net/socket.c:2595 ___sys_sendmsg+0x2a6/0x360 net/socket.c:2649 __sys_sendmmsg+0x2ca/0x510 net/socket.c:2735 __do_sys_sendmmsg net/socket.c:2764 [inline] __se_sys_sendmmsg net/socket.c:2761 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2761 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fcdb2f9ce59 RSP: 002b:00007fcdb3f45028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fcdb3215fa0 RCX: 00007fcdb2f9ce59 RDX: 0000000000000651 RSI: 0000200000000000 RDI: 0000000000000004 RBP: 00007fcdb3032e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcdb3216038 R14: 00007fcdb3215fa0 R15: 00007ffe07b7d908 rcu: rcu_preempt kthread starved for 10568 jiffies! g71209 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:27496 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x10/0x60 kernel/kcov.c:216 Code: 89 fb e8 13 00 00 00 48 8b 3d cc 02 04 0d 48 89 de 5b e9 b3 a3 57 00 cc cc cc f3 0f 1e fa 48 8b 04 24 65 48 8b 0d e0 d2 7c 7e <65> 8b 15 e1 d2 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 RSP: 0018:ffffc90000007d18 EFLAGS: 00000002 RAX: ffffffff81770cc4 RBX: ffff8880535b8340 RCX: ffffffff8ce93440 RDX: ffffffff8ce93440 RSI: 0000000000000010 RDI: 0000000000000000 RBP: 0000000000000010 R08: ffffffff8e8ae5ef R09: 1ffffffff1d15cbd R10: dffffc0000000000 R11: fffffbfff1d15cbe R12: 1ffff110171c5728 R13: dffffc0000000000 R14: ffff8880b8e2b940 R15: ffff8880b8e2b78c FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 000000006bae5000 CR4: 00000000003506f0 Call Trace: enqueue_hrtimer+0x104/0x380 kernel/time/hrtimer.c:1101 __run_hrtimer kernel/time/hrtimer.c:1771 [inline] __hrtimer_run_queues+0x62f/0xc10 kernel/time/hrtimer.c:1818 hrtimer_interrupt+0x39d/0x980 kernel/time/hrtimer.c:1880 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: dc 23 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 43 67 44 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2c 89 cb 80 f9 RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c6 RAX: cdd9798bb7c30d00 RBX: ffffffff81628c14 RCX: cdd9798bb7c30d00 RDX: 0000000000000001 RSI: ffffffff8acacb60 RDI: ffffffff8b1c7be0 RBP: ffffffff8ce07eb8 R08: ffff8880b8e36bab R09: 1ffff110171c6d75 R10: dffffc0000000000 R11: ffffed10171c6d76 R12: 1ffffffff19c0fbc R13: dffffc0000000000 R14: 1ffffffff19d2688 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:178 [inline] do_idle+0x334/0x5c0 kernel/sched/idle.c:302 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401 rest_init+0x2e2/0x300 init/main.c:744 arch_call_rest_init+0xe/0x10 init/main.c:840 start_kernel+0x459/0x4e0 init/main.c:1085 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b