rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2915/1:b..l P5757/1:b..l rcu: (detected by 0, t=10502 jiffies, g=8473, q=742 ncpus=2) task:udevd state:R running task stack:24968 pid:5757 ppid:5139 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7010 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_is_held_type+0x50/0x190 kernel/locking/lockdep.c:5818 Code: 3d e0 a5 e3 03 00 0f 84 03 01 00 00 65 8b 05 ef 4f 9c 75 85 c0 0f 85 f4 00 00 00 65 48 8b 1d e7 7f 9d 75 83 bb dc 0a 00 00 00 <0f> 85 df 00 00 00 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c 8f RSP: 0018:ffffc900044cf7d8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888028701e00 RCX: ffff888028701e00 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff88807a2014a0 RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff2e53ae4 R12: ffff88807a2014a0 R13: ffff88802557ee0c R14: 0000000000000002 R15: ffff88802459d250 lock_is_held include/linux/lockdep.h:288 [inline] mt_locked lib/maple_tree.c:-1 [inline] mt_slot lib/maple_tree.c:812 [inline] mas_slot lib/maple_tree.c:845 [inline] mas_validate_parent_slot lib/maple_tree.c:7035 [inline] mt_validate+0x7b1/0x4530 lib/maple_tree.c:7224 validate_mm+0xb1/0x420 mm/mmap.c:287 do_vmi_align_munmap+0x148a/0x1660 mm/mmap.c:2587 do_vmi_munmap+0x252/0x2d0 mm/mmap.c:2650 __vm_munmap+0x193/0x3c0 mm/mmap.c:2951 __do_sys_munmap mm/mmap.c:2968 [inline] __se_sys_munmap mm/mmap.c:2965 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:2965 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: 0033:0x7f97bd71e097 RSP: 002b:00007ffe0b6a9a58 EFLAGS: 00000246 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 000055c0d2e71310 RCX: 00007f97bd71e097 RDX: 000055c0d2e6ddd8 RSI: 0000000000000200 RDI: 00007f97bde94000 RBP: 000000000000000d R08: 000055c0d2e793c0 R09: 0000000000000003 R10: 0000000000000000 R11: 0000000000000246 R12: 000055c0d2e6e060 R13: 00007f97bdfc839c R14: 0000000000001a00 R15: 0000000000000009 task:kworker/u4:8 state:R running task stack:22616 pid:2915 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 preempt_schedule_irq+0xb5/0x140 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: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:ffffc9000bb07a40 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: daa7cab1a6a12700 RDX: 0000000000000000 RSI: ffffffff8aaac440 RDI: ffffffff8afc6900 RBP: ffffc9000bb07b48 R08: dffffc0000000000 R09: 1ffffffff21b0aa4 R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: 1ffff92001760f54 R13: ffffffff8cd2f760 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 rcu: rcu_preempt kthread starved for 10550 jiffies! g8473 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:27672 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 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 6.6.94-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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 63 f0 41 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: 00f920f3fc099f00 RBX: ffffffff81618a7b RCX: 00f920f3fc099f00 RDX: 0000000000000001 RSI: ffffffff8aaab2c0 RDI: ffffffff8afc6900 RBP: ffffc90000187f20 R08: ffff8880b8f36d4b R09: 1ffff110171e6da9 R10: dffffc0000000000 R11: ffffed10171e6daa R12: ffffffff8e49ab28 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110037cb780 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6b5ea77f98 CR3: 000000007d8b6000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 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