rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4323/1:b..l P4473/1:b..l P5091/1:b..l (detected by 0, t=10503 jiffies, g=14833, q=108 ncpus=2) task:modprobe state:R running task stack:23472 pid:5091 ppid:5020 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5710 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc9000481f878 EFLAGS: 00000206 RAX: ab67aa42d71e1100 RBX: ffff888027733b80 RCX: ab67aa42d71e1100 RDX: 0000000000000000 RSI: ffffffff8a8c22a0 RDI: ffffffff8adf1320 RBP: 0000000000000001 R08: ffff888027733b80 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000246 R14: ffff88801db1db58 R15: ffff888027734660 lock_is_held include/linux/lockdep.h:283 [inline] mt_locked lib/maple_tree.c:-1 [inline] mt_slot lib/maple_tree.c:816 [inline] mas_slot lib/maple_tree.c:849 [inline] mt_validate_nulls lib/maple_tree.c:7193 [inline] mt_validate+0x43d1/0x4cb0 lib/maple_tree.c:7249 validate_mm_mt+0xe2/0x440 mm/mmap.c:295 __split_vma+0x30/0x500 mm/mmap.c:2355 mprotect_fixup+0x5b1/0x800 mm/mprotect.c:623 do_mprotect_pkey+0x7fe/0xba0 mm/mprotect.c:792 __do_sys_mprotect mm/mprotect.c:819 [inline] __se_sys_mprotect mm/mprotect.c:816 [inline] __x64_sys_mprotect+0x7c/0x90 mm/mprotect.c:816 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe1a24f42c7 RSP: 002b:00007ffd21369588 EFLAGS: 00000206 ORIG_RAX: 000000000000000a RAX: ffffffffffffffda RBX: 00007fe1a24d1580 RCX: 00007fe1a24f42c7 RDX: 0000000000000001 RSI: 0000000000001000 RDI: 00007fe1a2212000 RBP: 00007ffd21369850 R08: 0000000000000000 R09: 00007fe1a22662e0 R10: 00007fe1a24d1580 R11: 0000000000000206 R12: 0000000000000020 R13: 000000718cc53f1a R14: 0000000000000000 R15: 00007fe1a2508310 task:udevd state:R running task stack:24528 pid:4473 ppid:3638 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6731 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6755 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x10d/0x120 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x128/0x190 kernel/sched/wait.c:208 sock_def_readable+0x15b/0x280 net/core/sock.c:3316 unix_dgram_sendmsg+0x1051/0x16e0 net/unix/af_unix.c:2085 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] sock_write_iter+0x2d9/0x3e0 net/socket.c:1143 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x4b1/0xa30 fs/read_write.c:584 ksys_write+0x14c/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4bd2ea7407 RSP: 002b:00007ffe089536b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f4bd3551880 RCX: 00007f4bd2ea7407 RDX: 0000000000000000 RSI: 00007ffe08953757 RDI: 000000000000000a RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007f4bd35516e8 R13: 0000000000000000 R14: 0000000000000000 R15: 0000563b6812db20 task:kworker/u4:6 state:R running task stack:24304 pid:4323 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_acquire+0x225/0x4a0 kernel/locking/lockdep.c:5666 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc900045cfac0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: a7c62b0883495900 RDX: 0000000000000000 RSI: ffffffff8a8c22a0 RDI: ffffffff8adf1320 RBP: ffffc900045cfbc8 R08: dffffc0000000000 R09: 1ffffffff215f248 R10: dffffc0000000000 R11: fffffbfff215f249 R12: 0000000000000000 R13: 1ffff920008b9f64 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xeb/0x600 net/batman-adv/network-coding.c:719 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread timer wakeup didn't happen for 10589 jiffies! g14833 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=9965 rcu: rcu_preempt kthread starved for 10592 jiffies! g14833 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:27760 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742 Code: 48 89 df e8 77 a3 9b f7 e9 44 ff ff ff e8 3d 07 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d a7 ca 4e 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0018:ffffffff8c807d88 EFLAGS: 000002c6 RAX: 9cea687e8c067900 RBX: ffffffff8a37e307 RCX: 9cea687e8c067900 RDX: 0000000000000001 RSI: ffffffff8a8c1120 RDI: ffffffff8adf1320 RBP: ffffffff8c807ec0 R08: ffff8880b8e3580b R09: 1ffff110171c6b01 R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 0000000000000000 R13: dffffc0000000000 R14: ffffffff8c8bc740 R15: 1ffffffff1900fbc FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd24342fb0 CR3: 000000005e89a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: default_idle_call+0x84/0xc0 kernel/sched/idle.c:109 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x250/0x680 kernel/sched/idle.c:323 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:422 rest_init+0x2dc/0x300 init/main.c:745 arch_call_rest_init+0xa/0xa init/main.c:905 start_kernel+0x493/0x53c init/main.c:1152 secondary_startup_64_no_verify+0xcf/0xdb