rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=7144/1/0x4000000000000000 softirq=48621/48622 fqs=0 rcu: (detected by 0, t=10505 jiffies, g=46461, q=285 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 19 Comm: rcu_exp_gp_kthr Not tainted 6.14.0-rc4-syzkaller-00282-g1973160c90d7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:32 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:87 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:123 [inline] RIP: 0010:lock_release+0x19d/0xa30 kernel/locking/lockdep.c:5868 Code: 3b 00 74 08 4c 89 f7 e8 71 99 89 00 4c 89 6c 24 50 48 c7 84 24 b0 00 00 00 00 00 00 00 9c 8f 84 24 b0 00 00 00 42 80 3c 3b 00 <74> 08 4c 89 f7 e8 59 98 89 00 48 8b 9c 24 b0 00 00 00 fa 48 c7 c7 RSP: 0018:ffffc90000a18b20 EFLAGS: 00000046 RAX: ffffffff94083710 RBX: 1ffff9200014317a RCX: ffffffff819cd9b0 RDX: 0000000000000000 RSI: ffffffff8c801c00 RDI: ffffffff8c801bc0 RBP: ffffc90000a18c60 R08: ffffffff903bc577 R09: 1ffffffff20778ae R10: dffffc0000000000 R11: fffffbfff20778af R12: 1ffff92000143170 R13: ffffffff89fcb7a2 R14: ffffc90000a18bd0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3de39c CR3: 000000003137a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_release include/linux/rcupdate.h:347 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] advance_sched+0xb32/0xca0 net/sched/sch_taprio.c:987 __run_hrtimer kernel/time/hrtimer.c:1801 [inline] __hrtimer_run_queues+0x59b/0xd30 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 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_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202 Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0a 83 99 f5 48 89 df e8 f2 cb 9a f5 e8 dd 35 c6 f5 fb bf 01 00 00 00 a2 0c 8c f5 65 8b 05 f3 7e 00 74 85 c0 74 06 5b c3 cc cc cc cc RSP: 0018:ffffc90000187d78 EFLAGS: 00000286 RAX: 6b233b98ee44cb00 RBX: ffff88801b0a8f08 RCX: ffffffff9a61a903 RDX: dffffc0000000000 RSI: ffffffff8c2aa4a0 RDI: 0000000000000001 RBP: ffff88801b0a8f48 R08: ffffffff903bc577 R09: 1ffffffff20778ae R10: dffffc0000000000 R11: fffffbfff20778af R12: ffffc9000ee77ab8 R13: dffffc0000000000 R14: ffff88801b0a8f08 R15: ffff88801b0a8f70 kthread_worker_fn+0x372/0xb70 kernel/kthread.c:1004 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: rcu_preempt kthread starved for 10505 jiffies! g46461 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:26104 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 14328 Comm: syz.0.3443 Not tainted 6.14.0-rc4-syzkaller-00282-g1973160c90d7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x1ba4/0x2d30 kernel/smp.c:885 Code: 03 84 c0 75 7e 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 30 f5 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 e0 f0 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00 RSP: 0018:ffffc9000ee678c0 EFLAGS: 00000293 RAX: ffffffff81b5ce05 RBX: 1ffff110170e88c9 RCX: ffff88802e990000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000ee67aa8 R08: ffffffff81b5cdd0 R09: 1ffffffff28a2713 R10: dffffc0000000000 R11: fffffbfff28a2714 R12: ffff8880b863f9c8 R13: ffff8880b8744648 R14: ffff8880b863f9c0 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2fb1cff8 CR3: 0000000061a48000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 kill_bdev block/bdev.c:90 [inline] blkdev_flush_mapping+0xfe/0x270 block/bdev.c:670 blkdev_put_whole block/bdev.c:677 [inline] bdev_release+0x460/0x700 block/bdev.c:1102 blkdev_release+0x15/0x20 block/fops.c:660 __fput+0x3e9/0x9f0 fs/file_table.c:464 task_work_run+0x24f/0x310 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2a/0x28e0 kernel/exit.c:938 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 __do_sys_exit_group kernel/exit.c:1098 [inline] __se_sys_exit_group kernel/exit.c:1096 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1096 x64_sys_call+0x26a8/0x26b0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3c47d8d169 Code: Unable to access opcode bytes at 0x7f3c47d8d13f. RSP: 002b:00007ffcc403a7a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3c47d8d169 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffcc403a80c R08: 00000004c403a89f R09: 00000000000927c0 R10: 0000000000007fd4 R11: 0000000000000246 R12: 000000000000029c R13: 00000000000927c0 R14: 0000000000043e4a R15: 00007ffcc403a860