rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4983/1:b..l P51/1:b..l (detected by 1, t=10503 jiffies, g=32201, q=328 ncpus=2) task:kworker/u4:3 state:R running task stack:25032 pid:51 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:ffffc90000bc7ac0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: d3cba6ed42c8db00 RDX: 0000000000000000 RSI: ffffffff8a8c1680 RDI: ffffffff8adefca0 RBP: ffffc90000bc7bc8 R08: dffffc0000000000 R09: fffffbfff215c449 R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: 0000000000000000 R13: 1ffff92000178f64 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 task:syz-executor state:R running task stack:21536 pid:4983 ppid:4954 flags:0x00004002 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:unwind_get_return_address+0x66/0x80 arch/x86/kernel/unwind_orc.c:324 Code: e8 3f 8e 98 00 48 8b 3b e8 77 ad 1c 00 85 c0 74 14 43 80 3c 37 00 74 08 48 89 df e8 24 8e 98 00 48 8b 03 eb 02 31 c0 5b 41 5e <41> 5f c3 89 d9 80 e1 07 80 c1 03 38 c1 7c ad 48 89 df e8 f3 8d 98 RSP: 0018:ffffc9000e5bf2b8 EFLAGS: 00000246 RAX: ffffffff8a1702b8 RBX: ffffc9000e5bf380 RCX: 0000000080000000 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffffff8a1702b8 RBP: ffffc9000e5bf350 R08: dffffc0000000000 R09: ffffc9000e5bf318 R10: fffff52001cb7e65 R11: 1ffff92001cb7e63 R12: ffff88802ba48000 R13: 1ffff92001cb7e84 R14: ffffffff816fb740 R15: 1ffff92001cb7e62 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122 save_stack+0xf3/0x1e0 mm/page_owner.c:127 __reset_page_owner+0x51/0x1a0 mm/page_owner.c:148 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1459 [inline] free_pcp_prepare mm/page_alloc.c:1509 [inline] free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3525 release_pages+0x1f92/0x2200 mm/swap.c:1035 __pagevec_release+0x6d/0xe0 mm/swap.c:1055 pagevec_release include/linux/pagevec.h:71 [inline] folio_batch_release include/linux/pagevec.h:135 [inline] shmem_undo_range+0x75b/0x2050 mm/shmem.c:946 shmem_truncate_range mm/shmem.c:1062 [inline] shmem_evict_inode+0x248/0xa40 mm/shmem.c:1171 evict+0x485/0x870 fs/inode.c:705 __dentry_kill+0x431/0x650 fs/dcache.c:611 dentry_kill+0xb8/0x290 fs/dcache.c:-1 dput+0xfa/0x1d0 fs/dcache.c:918 __fput+0x5e0/0x920 fs/file_table.c:328 task_work_run+0x1ca/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 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: 0033:0x7f6c2bd8fed7 RSP: 002b:00007ffde42ce4c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f6c2be11c05 RCX: 00007f6c2bd8fed7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffde42ce580 RBP: 00007ffde42ce580 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffde42cf610 R13: 00007f6c2be11c05 R14: 000000000004d5f0 R15: 00007ffde42cf650 rcu: rcu_preempt kthread timer wakeup didn't happen for 10580 jiffies! g32201 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=21572 rcu: rcu_preempt kthread starved for 10583 jiffies! g32201 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:27840 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:1965 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6667 Comm: syz.6.424 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:820 [inline] RIP: 0010:group_send_sig_info+0x107/0x250 kernel/signal.c:1446 Code: 89 f6 48 89 da e8 69 01 00 00 41 89 c5 e8 81 de c6 08 89 c5 31 ff 89 c6 e8 56 69 30 00 85 ed 74 10 e8 9d a3 1a 00 84 c0 74 0e e4 65 30 00 eb 56 e8 dd 65 30 00 eb 4f e8 56 de c6 08 89 c5 31 RSP: 0018:ffffc90000007e60 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffff8880271e9dc0 RCX: 6a538b7152d3e000 RDX: ffff8880271e9dc0 RSI: ffffffff8adefc80 RDI: ffffffff8adefc40 RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff215c449 R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: ffffffff815069da R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000011 FS: 00007f176e36b6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f176d7d6188 CR3: 000000007a387000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_bpf_send_signal+0x7b/0x150 kernel/trace/bpf_trace.c:840 irq_work_single+0xd1/0x230 kernel/irq_work.c:211 irq_work_run_list kernel/irq_work.c:242 [inline] irq_work_run+0x152/0x2e0 kernel/irq_work.c:251 __sysvec_irq_work+0xba/0x350 arch/x86/kernel/irq_work.c:22 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0x98/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline] RIP: 0010:native_apic_msr_write+0x35/0x50 arch/x86/include/asm/apic.h:206 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 ef c7 f7 02 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffc90004cafcb0 EFLAGS: 00000246 RAX: 00000000000000f6 RBX: ffffffff8c5e4b88 RCX: 000000000000083f RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff52000995f85 R10: fffff52000995f85 R11: 1ffff92000995f84 R12: ffff8880b8e33e01 R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000020 arch_irq_work_raise+0x82/0xd0 arch/x86/kernel/irq_work.c:31 irq_work_queue+0x95/0x140 kernel/irq_work.c:114 bpf_send_signal_common+0x2b2/0x420 kernel/trace/bpf_trace.c:879 ____bpf_send_signal kernel/trace/bpf_trace.c:888 [inline] bpf_send_signal+0x15/0x20 kernel/trace/bpf_trace.c:886 bpf_prog_7ba5217f62dcd359+0x38/0x3c bpf_dispatcher_nop_func include/linux/bpf.h:1011 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline] bpf_trace_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324 __bpf_trace_sys_enter+0x60/0x70 include/trace/events/syscalls.h:18 trace_sys_enter+0x6b/0x80 include/trace/events/syscalls.h:18 syscall_trace_enter+0xf0/0x150 kernel/entry/common.c:81 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:77 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f176d52ada9 Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25 RSP: 002b:00007f176e36ab40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007f176d7d6188 RCX: 00007f176d52ada9 RDX: 00007f176e36ab40 RSI: 00007f176e36ac70 RDI: 0000000000000011 RBP: 00007f176d7d6180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f176d7d6218 R14: 00007ffec6388de0 R15: 00007ffec6388ec8