rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4624/1:b..l P3638/1:b..l P8134/1:b..l P8128/1:b..l (detected by 0, t=10502 jiffies, g=42245, q=72 ncpus=2) task:rm state:R running task stack:24352 pid:8128 ppid:8087 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:debug_lockdep_rcu_enabled+0xb/0x30 kernel/rcu/update.c:280 Code: 6c 8a 48 c7 c6 80 28 6c 8a e8 f1 88 3c f7 0f 0b eb d1 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 31 c0 83 3d d7 9c ee 03 00 74 1d <83> 3d 62 d0 ee 03 00 74 14 65 48 8b 0d b4 fc f1 75 31 c0 83 b9 dc RSP: 0000:ffffc90003a97c08 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffffffff83f41deb RCX: ffff88802ba51dc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100fbab0e9 R10: ffffed100fbab0e9 R11: 1ffff1100fbab0e8 R12: dffffc0000000000 R13: 0000000000000710 R14: 0000000000000000 R15: ffff88807dd58740 rcu_read_unlock include/linux/rcupdate.h:820 [inline] blk_cgroup_congested+0x180/0x220 block/blk-cgroup.c:2019 __cgroup_throttle_swaprate+0x6d/0x1a0 mm/swapfile.c:3671 cgroup_throttle_swaprate include/linux/swap.h:672 [inline] do_anonymous_page mm/memory.c:4197 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5173 [inline] handle_mm_fault+0x2c3f/0x3e60 mm/memory.c:5294 do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340 handle_page_fault arch/x86/mm/fault.c:1431 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7ff7fc2f3134 RSP: 002b:00007ffc78ab8020 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 00007ff7fbf75420 RCX: 00007ff7fbf75c80 RDX: 00007ff7fbf75c80 RSI: 0000000000000040 RDI: 00007ff7fbf75c88 RBP: 0000000000001180 R08: 00007ff7fc316598 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000001 R14: 0000009e56dd0559 R15: 0000000000000000 task:syz.7.624 state:R running task stack:25408 pid:8134 ppid:5204 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:215 Code: 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 90 30 7e 0c 48 89 de 5b e9 47 68 4f 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d 64 8f 81 7e 65 8b 15 65 8f 81 7e 81 e2 00 01 ff 00 74 RSP: 0018:ffffc90003c672f0 EFLAGS: 00000246 RAX: ffffffff81d9a1eb RBX: 0000000000000001 RCX: 0000000000000002 RDX: ffff888057c61dc0 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100351da16 R10: ffffed100351da16 R11: 1ffff1100351da15 R12: 000000000000000a R13: dffffc0000000000 R14: 0000000000000001 R15: ffff88801a8ed0f0 __set_page_owner_handle+0x37b/0x3c0 mm/page_owner.c:182 __set_page_owner+0x41/0x60 mm/page_owner.c:195 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532 prep_new_page mm/page_alloc.c:2539 [inline] get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614 __folio_alloc+0xe/0x30 mm/page_alloc.c:5646 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243 shmem_alloc_folio mm/shmem.c:1589 [inline] shmem_alloc_and_acct_folio+0x42e/0xb60 mm/shmem.c:1613 shmem_get_folio_gfp+0x1361/0x3400 mm/shmem.c:1941 shmem_get_folio mm/shmem.c:2072 [inline] shmem_write_begin+0xee/0x3f0 mm/shmem.c:2556 generic_perform_write+0x2f7/0x5a0 mm/filemap.c:3862 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x44c/0x960 fs/read_write.c:584 ksys_write+0x143/0x240 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f134b98e1ff RSP: 002b:00007f134c8dedf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000400000 RCX: 00007f134b98e1ff RDX: 0000000000400000 RSI: 00007f13417f7000 RDI: 0000000000000005 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000010f7 R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000005 R13: 00007f134c8deef0 R14: 00007f134c8deeb0 R15: 00007f13417f7000 task:udevd state:R running task stack:23040 pid:3638 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754 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+0xf6/0x100 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+0x11b/0x180 kernel/sched/wait.c:208 sock_def_readable+0x15b/0x280 net/core/sock.c:3316 __netlink_sendskb net/netlink/af_netlink.c:1264 [inline] netlink_sendskb+0x97/0x130 net/netlink/af_netlink.c:1270 netlink_sendmsg+0x89e/0xbc0 net/netlink/af_netlink.c:1872 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x59b/0x970 net/socket.c:2519 ___sys_sendmsg+0x21c/0x290 net/socket.c:2573 __sys_sendmsg net/socket.c:2602 [inline] __do_sys_sendmsg net/socket.c:2611 [inline] __se_sys_sendmsg+0x19e/0x270 net/socket.c:2609 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7efe7f0a7407 RSP: 002b:00007ffeba5756e0 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007efe7f76f880 RCX: 00007efe7f0a7407 RDX: 0000000000000000 RSI: 00007ffeba575740 RDI: 0000000000000004 RBP: 000055815182a7b0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000b4 R13: 000055815180d9e0 R14: 0000000000000000 R15: 0000000000000000 task:kworker/u4:13 state:R running task stack:22496 pid:4624 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 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+0x20f/0x490 kernel/locking/lockdep.c:5666 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 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b RSP: 0018:ffffc90004f7fac0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 1b49ba3e5c4bc600 RDX: 0000000000000000 RSI: ffffffff8a6c1780 RDI: ffffffff8abef920 RBP: ffffc90004f7fbc8 R08: dffffc0000000000 R09: fffffbfff2119049 R10: fffffbfff2119049 R11: 1ffffffff2119048 R12: 0000000000000001 R13: 1ffff920009eff64 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+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 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 starved for 10622 jiffies! g42245 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:27200 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 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: 8132 Comm: syz.8.625 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ae 05 49 f7 48 89 df e8 06 cb 49 f7 e8 d1 bd 6c f7 fb bf 01 00 00 00 96 43 3d f7 65 8b 05 27 f1 e7 75 85 c0 74 02 5b c3 e8 c4 02 e6 RSP: 0018:ffffc900043a7b98 EFLAGS: 00000282 RAX: 19806e86c487cf00 RBX: ffff888079d70000 RCX: 19806e86c487cf00 RDX: dffffc0000000000 RSI: ffffffff8a6c0600 RDI: 0000000000000001 RBP: ffff888079d70298 R08: dffffc0000000000 R09: ffffed100f3ae001 R10: ffffed100f3ae001 R11: 1ffff1100f3ae000 R12: 1ffff1100f3ae053 R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007fbbe615a6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff7fbf765b8 CR3: 00000000404e5000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x1163/0x1350 kernel/signal.c:2874 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fbbe538f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fbbe615a0e8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007fbbe55e5fa8 RCX: 00007fbbe538f749 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fbbe55e5fac RBP: 00007fbbe55e5fa0 R08: 001c09d36e2b24d4 R09: 0000000000000000 R10: 000000000000000b R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbbe55e6038 R14: 00007ffefbbe77c0 R15: 00007ffefbbe78a8