rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11758/1:b..l P20177/1:b..l P3557/1:b..l rcu: (detected by 0, t=10502 jiffies, g=133449, q=397 ncpus=2) task:kworker/u4:12 state:R running task stack:19976 pid:3557 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 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:batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:845 [inline] RIP: 0010:batadv_iv_ogm_schedule+0x9a9/0xf10 net/batman-adv/bat_iv_ogm.c:870 Code: 03 00 00 48 8b 44 24 40 48 c1 e8 03 48 89 44 24 58 49 8d 5f 78 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 48 89 df e8 cd 17 96 f7 48 8b 1b 48 b8 00 00 00 00 00 fc ff RSP: 0000:ffffc9000d1579c0 EFLAGS: 00000246 RAX: 1ffff1100f9d920f RBX: ffff88807cec9078 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffffffff8b1c8e40 RDI: ffffffff8b1c8e00 RBP: ffffc9000d157b00 R08: dffffc0000000000 R09: 1ffffffff2238aa0 R10: dffffc0000000000 R11: fffffbfff2238aa1 R12: 000000010002329e R13: ffff88802ce24000 R14: ffff88802ce24078 R15: ffff88807cec9000 batadv_iv_send_outstanding_bat_ogm_packet+0x733/0x850 net/batman-adv/bat_iv_ogm.c:1714 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730 worker_thread+0xa55/0xfc0 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:modprobe state:R running task stack:24232 pid:20177 ppid:9988 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] change_pte_range mm/mprotect.c:286 [inline] change_pmd_range mm/mprotect.c:420 [inline] change_pud_range mm/mprotect.c:453 [inline] change_p4d_range mm/mprotect.c:476 [inline] change_protection_range mm/mprotect.c:504 [inline] change_protection+0x278a/0x3200 mm/mprotect.c:538 mprotect_fixup+0x929/0xca0 mm/mprotect.c:666 do_mprotect_pkey+0x7c2/0xcb0 mm/mprotect.c:819 __do_sys_mprotect mm/mprotect.c:840 [inline] __se_sys_mprotect mm/mprotect.c:837 [inline] __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:837 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6ddbe512c7 RSP: 002b:00007fff3740b118 EFLAGS: 00000206 ORIG_RAX: 000000000000000a RAX: ffffffffffffffda RBX: 00007f6ddbb306b0 RCX: 00007f6ddbe512c7 RDX: 0000000000000001 RSI: 0000000000001000 RDI: 00007f6ddbb24000 RBP: 00007fff3740b3e0 R08: 0000000000000000 R09: 00007f6ddbbc32e0 R10: 00007f6ddbb306b0 R11: 0000000000000206 R12: 0000000000000038 R13: 0000037e56d471c8 R14: 0000000000000000 R15: 00007f6ddbe65310 task:syz-executor state:R running task stack:21320 pid:11758 ppid:11737 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1107 [inline] copy_pmd_range mm/memory.c:1168 [inline] copy_pud_range mm/memory.c:1205 [inline] copy_p4d_range mm/memory.c:1229 [inline] copy_page_range+0x2ba0/0x3670 mm/memory.c:1323 dup_mmap kernel/fork.c:768 [inline] dup_mm kernel/fork.c:1693 [inline] copy_mm+0x1281/0x1d80 kernel/fork.c:1742 copy_process+0x16f7/0x3d80 kernel/fork.c:2507 kernel_clone+0x24b/0x8a0 kernel/fork.c:2915 __do_sys_clone kernel/fork.c:3058 [inline] __se_sys_clone kernel/fork.c:3042 [inline] __x64_sys_clone+0x1b7/0x230 kernel/fork.c:3042 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f49c6fc5852 RSP: 002b:00007ffe2e9f93d0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe2e9f93d0 RCX: 00007f49c6fc5852 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe2e9f955c R08: 0000000000000000 R09: 0000000000000001 R10: 000055556b7f07d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000001a9099 R15: 00007ffe2e9f95b0 rcu: rcu_preempt kthread starved for 6272 jiffies! g133449 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:27496 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 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+0x313/0x1590 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: 39 21 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 e3 f3 41 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80 RSP: 0018:ffffc90000187de0 EFLAGS: 000002c6 RAX: b7742255d2abc000 RBX: ffffffff8162a8f1 RCX: b7742255d2abc000 RDX: 0000000000000001 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8e60 RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65 R10: dffffc0000000000 R11: ffffed10171e6d66 R12: 1ffff92000030fc8 R13: dffffc0000000000 R14: 1ffff110036cd780 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000004b000 CR3: 00000000192b5000 CR4: 00000000003506e0 Call Trace: 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+0x221/0x590 kernel/sched/idle.c:302 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323 secondary_startup_64_no_verify+0x179/0x17b