syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=3004/1/0x4000000000000000 softirq=37347/37350 fqs=5
rcu: 	(detected by 0, t=10502 jiffies, g=25889, q=565 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5828 Comm: syz-executor Not tainted 6.15.0-syzkaller-07774-g90b83efa6701 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:srso_alias_safe_ret+0x0/0x7 arch/x86/lib/retpoline.S:172
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <48> 8d 64 24 08 c3 cc e8 f4 ff ff ff 0f 0b cc cc cc cc cc cc cc cc
RSP: 0018:ffffc90000a08b48 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 0000000000000012 RCX: 7b531cfdfc34c200
RDX: 0000000000000001 RSI: ffffffff8be263e0 RDI: ffffffff8be263a0
RBP: ffffc90000a08c78 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200014116c R12: dffffc0000000000
R13: ffffffff84c5b8c2 R14: ffffffff99c6f948 R15: 1ffff9200014117c
FS:  0000555590c4c500(0000) GS:ffff888125d66000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5cbf5e6880 CR3: 000000005e726000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 srso_alias_return_thunk+0x5/0xfbef5 arch/x86/lib/retpoline.S:182
 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
 rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:745
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x4b/0x3e0 kernel/locking/lockdep.c:5882
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x70/0x110 kernel/locking/spinlock.c:194
 debug_object_activate+0x2e2/0x420 lib/debugobjects.c:836
 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline]
 debug_activate kernel/time/hrtimer.c:484 [inline]
 enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1088
 __run_hrtimer kernel/time/hrtimer.c:1778 [inline]
 __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x17c6/0x2390 arch/x86/kernel/unwind_orc.c:-1
Code: 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 0e 0b 00 00 49 0f bf 04 24 48 01 c6 4c 89 f7 48 89 da e8 4c 0e 00 00 84 c0 <0f> 84 47 01 00 00 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 20 0f
RSP: 0018:ffffc9000404f3d8 EFLAGS: 00000202
RAX: 1ffff92000809e01 RBX: ffffffff903f3fe8 RCX: 0000000000000001
RDX: ffffc9000404f4e8 RSI: dffffc0000000000 RDI: ffffc9000404fdf0
RBP: dffffc0000000000 R08: ffffc9000404fdf0 R09: ffffc9000404f4f8
R10: dffffc0000000000 R11: fffff52000809ea1 R12: ffffc9000404fdf0
R13: ffffc9000404f4f8 R14: ffffc9000404f4a8 R15: 1ffffffff207e7fd
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2380 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4744
 f2fs_destroy_node_manager+0x322/0xcc0 fs/f2fs/node.c:3369
 f2fs_put_super+0xb15/0x1170 fs/f2fs/super.c:1694
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1760
 kill_f2fs_super+0x390/0x6c0 fs/f2fs/super.c:5032
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1432
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c4a18fc97
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fff3aaaf4c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f1c4a21089d RCX: 00007f1c4a18fc97
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff3aaaf580
RBP: 00007fff3aaaf580 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff3aab0610
R13: 00007f1c4a21089d R14: 0000000000036305 R15: 00007fff3aab0650
 </TASK>
rcu: rcu_preempt kthread starved for 10423 jiffies! g25889 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:27128 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5392 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6781
 __schedule_loop kernel/sched/core.c:6859 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6874
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5834 Comm: syz-executor Not tainted 6.15.0-syzkaller-07774-g90b83efa6701 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_single+0x3ae/0x590 kernel/smp.c:679
Code: e6 01 31 ff e8 23 92 0b 00 41 83 e6 01 75 11 e8 d8 8d 0b 00 4d 89 fe eb 3f e8 ce 8d 0b 00 eb 3c 4d 89 fe f3 90 43 0f b6 04 2c <84> c0 75 0f f7 03 01 00 00 00 74 1d e8 b1 8d 0b 00 eb e6 89 d9 80
RSP: 0018:ffffc900031178e0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffffc90003117928 RCX: ffff888025af5a00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900031179e0 R08: ffffffff8fa0b1b7 R09: 1ffffffff1f41636
R10: dffffc0000000000 R11: ffffffff816fe060 R12: 1ffff92000622f25
R13: dffffc0000000000 R14: 1ffff92000622f20 R15: 1ffff92000622f20
FS:  0000555576320500(0000) GS:ffff888125c66000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e719ff8 CR3: 000000005dc50000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 rcu_barrier+0x360/0x570 kernel/rcu/tree.c:3834
 flush_rcu_work+0x84/0xb0 kernel/workqueue.c:4304
 kvfree_rcu_barrier+0x12b/0x160 mm/slab_common.c:2083
 kmem_cache_destroy+0x2e/0x160 mm/slab_common.c:492
 f2fs_put_super+0xb8c/0x1170 fs/f2fs/super.c:1707
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1760
 kill_f2fs_super+0x390/0x6c0 fs/f2fs/super.c:5032
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1432
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe6b318fc97
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe8774b808 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fe6b321089d RCX: 00007fe6b318fc97
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe8774b8c0
RBP: 00007ffe8774b8c0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe8774c950
R13: 00007fe6b321089d R14: 0000000000036343 R15: 00007ffe8774c990
 </TASK>