rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=669/1/0x4000000000000000 softirq=11940/11944 fqs=41 
	(detected by 0, t=10502 jiffies, g=12497, q=159)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5553 Comm: syz.1.279 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline]
RIP: 0010:__lock_acquire+0x12e1/0x7c60 kernel/locking/lockdep.c:5009
Code: 07 89 c3 81 e3 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 c0 70 fb 8f be 08 00 00 00 e8 67 1b 60 00 48 0f a3 1d 2f 63 9f 0e <73> 1a 48 8d 04 5b c1 e0 06 48 8d 98 80 ef 93 8f 49 b8 00 00 00 00
RSP: 0018:ffffc90000dd0860 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff815c0d89
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffb70c0
RBP: ffffc90000dd0ab0 R08: dffffc0000000000 R09: fffffbfff1ff6e19
R10: fffffbfff1ff6e19 R11: 1ffffffff1ff6e18 R12: 00000000f273e68c
R13: ffff88802a9e1dc0 R14: 000000003196d937 R15: ffff88802a9e2948
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32422ff8 CR3: 000000000be8e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x63/0x340 lib/debugobjects.c:749
 debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline]
 debug_deactivate+0x1d/0x1c0 kernel/time/hrtimer.c:471
 __run_hrtimer kernel/time/hrtimer.c:1658 [inline]
 __hrtimer_run_queues+0x2db/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 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:ffffc900035ef2e0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 9f9d88c9635b8000
RDX: 0000000000000000 RSI: ffffffff8a0b2860 RDI: ffffffff8a599340
RBP: ffffc900035ef400 R08: dffffc0000000000 R09: fffffbfff1ff6e19
R10: fffffbfff1ff6e19 R11: 1ffffffff1ff6e18 R12: ffffffff8c11c360
R13: 1ffff920006bde68 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 lock_page_memcg+0xa9/0x410 mm/memcontrol.c:2047
 page_remove_rmap+0x2a/0x10f0 mm/rmap.c:1351
 zap_pte_range mm/memory.c:1384 [inline]
 zap_pmd_range mm/memory.c:1505 [inline]
 zap_pud_range mm/memory.c:1534 [inline]
 zap_p4d_range mm/memory.c:1555 [inline]
 unmap_page_range+0xfbc/0x2520 mm/memory.c:1576
 unmap_vmas+0x11b/0x230 mm/memory.c:1653
 exit_mmap+0x38f/0x5f0 mm/mmap.c:3212
 __mmput+0x115/0x3b0 kernel/fork.c:1127
 exit_mm+0x567/0x6c0 kernel/exit.c:550
 do_exit+0x5a1/0x20a0 kernel/exit.c:870
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 get_signal+0x6ca/0x12c0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f62115fdbe9
Code: Unable to access opcode bytes at RIP 0x7f62115fdbbf.
RSP: 002b:00007f620f8650e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f6211824fa8 RCX: 00007f62115fdbe9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f6211824fac
RBP: 00007f6211824fa0 R08: 000dc42ee3000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6211825038 R14: 00007ffeef27f100 R15: 00007ffeef27f1e8
 </TASK>
rcu: rcu_preempt kthread starved for 10419 jiffies! g12497 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:28128 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 5551 Comm: syz.5.280 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1690 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202
Code: 66 2e 0f 1f 84 00 00 00 00 00 53 48 89 fb e8 17 00 00 00 48 8b 3d c0 ac f1 0b 48 89 de 5b e9 77 99 43 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 94 ab 8a 7e 65 8b 15 95 ab 8a 7e 81 e2 00
RSP: 0018:ffffc90003bdf6f8 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc90014400000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90003bdf838 R08: dffffc0000000000 R09: fffffbfff1ff6e41
R10: fffffbfff1ff6e41 R11: 1ffffffff1ff6e40 R12: ffff8880b9140588
R13: 1ffff110172280b1 R14: ffff8880b903b380 R15: 0000000000000001
 csd_lock_wait kernel/smp.c:440 [inline]
 smp_call_function_many_cond+0xbab/0xd70 kernel/smp.c:969
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
 invalidate_bdev+0x8a/0xb0 block/bdev.c:86
 btrfs_get_bdev_and_sb+0x152/0x1e0 fs/btrfs/volumes.c:519
 btrfs_open_one_device fs/btrfs/volumes.c:656 [inline]
 open_fs_devices+0x1cc/0xd10 fs/btrfs/volumes.c:1307
 btrfs_mount_root+0x4e0/0x8c0 fs/btrfs/super.c:1725
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 fc_mount fs/namespace.c:996 [inline]
 vfs_kern_mount+0xba/0x150 fs/namespace.c:1026
 btrfs_mount+0x2d7/0xa50 fs/btrfs/super.c:1811
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3014
 do_mount fs/namespace.c:3357 [inline]
 __do_sys_mount fs/namespace.c:3565 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3542
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f83a08c438a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f839eb29e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f839eb29ef0 RCX: 00007f83a08c438a
RDX: 00002000000055c0 RSI: 0000200000005600 RDI: 00007f839eb29eb0
RBP: 00002000000055c0 R08: 00007f839eb29ef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000005600
R13: 00007f839eb29eb0 R14: 0000000000005599 R15: 0000200000000280
 </TASK>