rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6674/2:b..l P2107/1:b..l rcu: (detected by 0, t=10502 jiffies, g=16345, q=236 ncpus=2) task:kworker/u4:6 state:R running task stack:24776 pid:2107 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 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:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00 RSP: 0018:ffffc90004ff7a40 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 036c8969464c3f00 RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc6b00 RBP: ffffc90004ff7b48 R08: dffffc0000000000 R09: 1ffffffff21b50a0 R10: dffffc0000000000 R11: fffffbfff21b50a1 R12: 1ffff920009fef54 R13: ffffffff8cd2fee0 R14: 0000000000000246 R15: dffffc0000000000 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/0x610 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 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.3.226 state:R running task stack:25736 pid:6674 ppid:5793 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00 RSP: 0018:ffffc9001989f240 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 636570d507644600 RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc6b00 RBP: ffffc9001989f348 R08: dffffc0000000000 R09: 1ffffffff21b50a0 R10: dffffc0000000000 R11: fffffbfff21b50a1 R12: 1ffff92003313e54 R13: ffffffff8cd2fee0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline] percpu_ref_tryget+0x31/0x180 include/linux/percpu-refcount.h:266 css_tryget include/linux/cgroup_refcnt.h:45 [inline] get_mem_cgroup_from_mm+0x102/0x290 mm/memcontrol.c:1065 __mem_cgroup_charge+0x15/0x80 mm/memcontrol.c:7068 mem_cgroup_charge include/linux/memcontrol.h:686 [inline] wp_page_copy mm/memory.c:3117 [inline] do_wp_page+0x14fe/0x3630 mm/memory.c:3468 handle_pte_fault mm/memory.c:5041 [inline] __handle_mm_fault mm/memory.c:5166 [inline] handle_mm_fault+0x12d4/0x4920 mm/memory.c:5331 do_user_addr_fault+0x738/0x12e0 arch/x86/mm/fault.c:1373 handle_page_fault arch/x86/mm/fault.c:1465 [inline] exc_page_fault+0x67/0x110 arch/x86/mm/fault.c:1521 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0010:__put_user_nocheck_4+0x7/0x10 arch/x86/lib/putuser.S:98 Code: 01 ca c3 f3 0f 1e fa 48 89 cb 48 c1 fb 3f 48 09 d9 0f 01 cb 89 01 31 c9 0f 01 ca c3 90 90 90 90 90 90 90 f3 0f 1e fa 0f 01 cb <89> 01 31 c9 0f 01 ca c3 90 f3 0f 1e fa 48 89 cb 48 c1 fb 3f 48 09 RSP: 0018:ffffc9001989f8d8 EFLAGS: 00050206 RAX: 0000000000000088 RBX: 0000000000000088 RCX: 000020000010e030 RDX: ffff888024a7bc00 RSI: 0000000000000042 RDI: 00000000ffffffff RBP: ffffc9001989fa70 R08: ffffffff8e4a8d6f R09: 1ffffffff1c951ad R10: dffffc0000000000 R11: fffffbfff1c951ae R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000042 R15: 000020000010e000 ____sys_recvmsg+0x388/0x5b0 net/socket.c:2827 ___sys_recvmsg+0x1b6/0x510 net/socket.c:2856 do_recvmmsg+0x360/0x7d0 net/socket.c:2950 __sys_recvmmsg net/socket.c:3029 [inline] __do_sys_recvmmsg net/socket.c:3052 [inline] __se_sys_recvmmsg net/socket.c:3045 [inline] __x64_sys_recvmmsg+0x191/0x240 net/socket.c:3045 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6f8198f749 RSP: 002b:00007f6f828af038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f6f81be5fa0 RCX: 00007f6f8198f749 RDX: 000000000000f000 RSI: 0000200000000d00 RDI: 0000000000000005 RBP: 00007f6f81a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000010002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6f81be6038 R14: 00007f6f81be5fa0 R15: 00007ffefba60f98 rcu: rcu_preempt kthread starved for 10358 jiffies! g16345 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:27752 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 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 10/02/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148 Code: 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 c3 64 39 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56 RSP: 0018:ffffc90000187de0 EFLAGS: 000002c2 RAX: 1cce6bee3398fc00 RBX: ffffffff816187ab RCX: 1cce6bee3398fc00 RDX: 0000000000000001 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6b00 RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65 R10: dffffc0000000000 R11: ffffed10171e6d66 R12: ffffffff8e4a8d68 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100384f780 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000004a030 CR3: 000000001cbb1000 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:170 [inline] do_idle+0x1eb/0x510 kernel/sched/idle.c:282 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323 secondary_startup_64_no_verify+0x179/0x17b