rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4373/1:b..l P5822/1:b..l P7072/1:b..l rcu: (detected by 1, t=10502 jiffies, g=11557, q=323 ncpus=2) task:syz.3.203 state:R running task stack:27080 pid:7072 tgid:7062 ppid:5817 task_flags:0x40044c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5870 Code: e9 0b 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 02 d8 ec 0e 0f 82 74 02 00 00 8b 35 9a 07 ed 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 d9 e8 0b 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc9001a82ef28 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e3bfc00 RCX: 00000000ef9d33e4 RDX: 0000000000000000 RSI: ffffffff8dbbd24b RDI: ffffffff8bf48920 RBP: 0000000000000002 R08: 0ac0d5affe09d4ff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] free_unref_folios+0x999/0x1630 mm/page_alloc.c:2782 folios_put_refs+0x56f/0x740 mm/swap.c:992 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x58f/0x1150 mm/shmem.c:1125 shmem_truncate_range mm/shmem.c:1237 [inline] shmem_evict_inode+0x3a1/0xbe0 mm/shmem.c:1365 evict+0x3e3/0x920 fs/inode.c:810 iput_final fs/inode.c:1898 [inline] iput fs/inode.c:1924 [inline] iput+0x521/0x880 fs/inode.c:1910 dentry_unlink_inode+0x29c/0x480 fs/dcache.c:457 __dentry_kill+0x1d0/0x600 fs/dcache.c:660 dput.part.0+0x4b1/0x9b0 fs/dcache.c:902 dput+0x1f/0x30 fs/dcache.c:892 __fput+0x51c/0xb70 fs/file_table.c:473 task_work_run+0x150/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xafb/0x2c30 kernel/exit.c:953 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbd18f8e969 RSP: 002b:00007fbd19e1a0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fbd191b6088 RCX: 00007fbd18f8e969 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbd191b6088 RBP: 00007fbd191b6080 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbd191b608c R13: 0000000000000000 R14: 00007ffd6d5095e0 R15: 00007ffd6d5096c8 task:syz-executor state:R running task stack:24024 pid:5822 tgid:5822 ppid:5805 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6947 preempt_schedule_thunk+0x16/0x30 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:1194 [inline] copy_pmd_range mm/memory.c:1255 [inline] copy_pud_range mm/memory.c:1292 [inline] copy_p4d_range mm/memory.c:1316 [inline] copy_page_range+0x1948/0x5f80 mm/memory.c:1410 dup_mmap kernel/fork.c:726 [inline] dup_mm kernel/fork.c:1734 [inline] copy_mm kernel/fork.c:1786 [inline] copy_process+0x862b/0x91a0 kernel/fork.c:2429 kernel_clone+0xfc/0x960 kernel/fork.c:2844 __do_sys_clone+0xce/0x120 kernel/fork.c:2987 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcddcb851d3 RSP: 002b:00007ffc17af1328 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcddcb851d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555752fd7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000030fbf R15: 00007ffc17af14c0 task:kworker/u8:8 state:R running task stack:23320 pid:4373 tgid:4373 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x11/0x90 kernel/kcov.c:246 Code: cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 47 d0 e8 11 <65> 8b 05 58 d0 e8 11 a9 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 RSP: 0018:ffffc9000de2fb28 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffff8880648892c0 RCX: ffffffff8b3a7fd9 RDX: ffff888035220000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000258 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 rcu_read_lock include/linux/rcupdate.h:842 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xc19/0x1030 net/batman-adv/network-coding.c:719 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g11557 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=9415 rcu: rcu_preempt kthread starved for 10502 jiffies! g11557 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:28280 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 7087 Comm: syz.1.206 Not tainted 6.15.0-rc6-syzkaller-00080-g1a80a098c606 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x10/0x70 kernel/kcov.c:217 Code: 00 00 5b e9 52 bd 15 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 34 24 65 48 8b 15 c8 c9 e8 11 <65> 8b 05 d9 c9 e8 11 a9 00 01 ff 00 74 1d f6 c4 01 74 43 a9 00 00 RSP: 0018:ffffc90000007d88 EFLAGS: 00000046 RAX: 0000000000010002 RBX: ffff88804afcf340 RCX: ffffffff8980f312 RDX: ffff88802e4ca440 RSI: ffffffff8981b3ab RDI: 0000000000000004 RBP: ffff8880367d4400 R08: 0000000000000004 R09: 0000000000000002 R10: 0000000000000002 R11: 0000000000000000 R12: 184d056be7415975 R13: 184d056be7415975 R14: 0000000000000002 R15: ffff8880367d5410 FS: 00007fb1074626c0(0000) GS:ffff8881249df000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ee09ff8 CR3: 0000000022b45000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: advance_sched+0x5fb/0xc80 net/sched/sch_taprio.c:980 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 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 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 06 84 28 f6 48 89 df e8 ae d7 28 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 05 44 19 f6 65 8b 05 fe 73 34 08 85 c0 74 16 5b RSP: 0018:ffffc9001a84fca8 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffff8880b8427840 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff8dbe285d RDI: ffffffff8bf48920 RBP: 0000000000000283 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff9084ff17 R11: 0000000000000000 R12: 0000000000000000 R13: 0000002ed782b4c7 R14: dffffc0000000000 R15: ffff8880b8427840 clock_was_set+0x599/0x870 kernel/time/hrtimer.c:972 do_settimeofday64+0x323/0x4d0 kernel/time/timekeeping.c:1407 do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195 __do_sys_clock_settime kernel/time/posix-timers.c:1140 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1124 [inline] __x64_sys_clock_settime+0x1c1/0x2a0 kernel/time/posix-timers.c:1124 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb10658e969 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:00007fb107462038 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007fb1067b6080 RCX: 00007fb10658e969 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000 RBP: 00007fb106610ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb1067b6080 R15: 00007fff97987f78