rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6878/1:b..l P22238/1:b..l rcu: (detected by 0, t=10503 jiffies, g=126497, q=202 ncpus=2) task:syz-executor state:R running task stack:23728 pid:22238 tgid:22238 ppid:22225 task_flags:0x400140 flags:0x00000000 Call Trace: <TASK> context_switch kernel/sched/core.c:5377 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6764 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6943 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1201 [inline] copy_pmd_range mm/memory.c:1262 [inline] copy_pud_range mm/memory.c:1299 [inline] copy_p4d_range mm/memory.c:1323 [inline] copy_page_range+0x1e7f/0x5690 mm/memory.c:1421 dup_mmap kernel/fork.c:748 [inline] dup_mm kernel/fork.c:1700 [inline] copy_mm kernel/fork.c:1752 [inline] copy_process+0x7ccb/0x8c50 kernel/fork.c:2403 kernel_clone+0xfd/0x960 kernel/fork.c:2815 __do_sys_clone+0xba/0x100 kernel/fork.c:2958 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9143b83653 RSP: 002b:00007ffd6f13a8f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9143b83653 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555740197d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000001e02d5 R15: 00007ffd6f13aa90 </TASK> task:kworker/u8:25 state:R running task stack:21856 pid:6878 tgid:6878 ppid:2 task_flags:0x4208160 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: <TASK> context_switch kernel/sched/core.c:5377 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6764 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7086 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire.part.0+0x155/0x380 kernel/locking/lockdep.c:5816 Code: b8 ff ff ff ff 65 0f c1 05 70 dd 6b 7e 83 f8 01 0f 85 d0 01 00 00 9c 58 f6 c4 02 0f 85 e5 01 00 00 48 85 ed 0f 85 b6 01 00 00 <48> b8 00 00 00 00 00 fc ff df 48 01 c3 48 c7 03 00 00 00 00 48 c7 RSP: 0018:ffffc9000441fa40 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 1ffff92000883f49 RCX: 00000000fba079c6 RDX: 0000000000000001 RSI: ffffffff8b6cef80 RDI: ffffffff8bd34d40 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2dd7b98 R10: ffffffff96ebdcc7 R11: 0000000000000002 R12: 0000000000000000 R13: ffffffff8e1bcc80 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0x16a/0x1060 net/batman-adv/network-coding.c:719 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> rcu: rcu_preempt kthread timer wakeup didn't happen for 10500 jiffies! g126497 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=160408 rcu: rcu_preempt kthread starved for 10501 jiffies! g126497 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28344 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5377 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6841 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6856 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2024 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2226 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 26479 Comm: syz.0.5581 Not tainted 6.14.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xc/0x70 kernel/kcov.c:217 Code: cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 48 8b 15 54 05 4a 7e <65> 8b 05 55 05 4a 7e a9 00 01 ff 00 48 8b 34 24 74 1d f6 c4 01 74 RSP: 0000:ffffc90000a18e28 EFLAGS: 00000002 RAX: 0000000000010000 RBX: 0000000000000001 RCX: ffffffff81a70c68 RDX: ffff888029530000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff888078857340 R13: ffff8880b872c780 R14: ffff8880b872c680 R15: ffffffff896a1330 FS: 000055555cb59500(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1da77f1d58 CR3: 0000000069a5e000 CR4: 00000000003526f0 DR0: 0000000000000007 DR1: 000000000000000b DR2: 0000000000000002 DR3: 0000000000000009 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: <NMI> </NMI> <IRQ> trace_hrtimer_expire_exit include/trace/events/timer.h:306 [inline] __run_hrtimer kernel/time/hrtimer.c:1804 [inline] __hrtimer_run_queues+0x863/0xae0 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x3e5/0x6f0 kernel/locking/lockdep.c:5859 Code: 7e 83 f8 01 0f 85 fe 01 00 00 9c 58 f6 c4 02 0f 85 e9 01 00 00 48 f7 04 24 00 02 00 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 c7 43 08 00 00 00 00 48 8b 84 24 88 RSP: 0000:ffffc9000c5a7cf0 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920018b4fa0 RCX: 0000000000000004 RDX: 1ffff110052a615d RSI: ffffffff8b6cef80 RDI: ffffffff8bd34d40 RBP: ffffffffffffffff R08: 0000000000000001 R09: fffffbfff2dd7bad R10: ffffffff96ebdd6f R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: ffff888029530ae8 R15: ffff888029530000 rcu_lock_release include/linux/rcupdate.h:347 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] lock_vma_under_rcu+0x6be/0x980 mm/memory.c:6388 do_user_addr_fault+0x457/0x13f0 arch/x86/mm/fault.c:1328 handle_page_fault arch/x86/mm/fault.c:1480 [inline] exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f1da6944826 Code: 8d 3c 30 4c 89 de 4c 89 54 24 38 e8 94 86 04 00 4c 8b 54 24 38 85 c0 0f 85 57 01 00 00 48 8b 44 24 28 48 89 df 4c 89 54 24 38 <4c> 89 93 98 06 00 00 48 89 83 90 06 00 00 48 8d 83 10 03 00 00 4c RSP: 002b:00007ffe3f459ba0 EFLAGS: 00010246 RAX: 00007f1da77d1000 RBX: 00007f1da77f16c0 RCX: 00007f1da698cea7 RDX: 0000000000000003 RSI: 0000000000020000 RDI: 00007f1da77f16c0 RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000021000 R11: 0000000000000206 R12: 00007ffe3f459cf0 R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000 </TASK>