syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P25416/1:b..l P14249/1:b..l
rcu: 	(detected by 0, t=10505 jiffies, g=106909, q=753 ncpus=2)
task:syz-executor    state:R  running task     stack:22360 pid:14249 tgid:14249 ppid:14233  task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7188
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
 irqentry_exit+0x14f/0x730 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 e1 14 06 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 cb 0f 97 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 9b a0 6e ff cc 48 8d 3d 98 4c 92
RSP: 0018:ffffc9000729f0d8 EFLAGS: 00000286
RAX: 430c4aa65330c000 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000005a44979c RSI: ffffffff8e216b62 RDI: ffffffff8c28aa60
RBP: ffffffff8176e256 R08: ffffffff8176e256 R09: ffffffff8e95cd60
R10: dffffc0000000000 R11: ffffffff81b0d880 R12: 0000000000000002
R13: ffffffff8e95cd60 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 rcu_read_lock include/linux/rcupdate.h:838 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 free_unref_folios+0xcec/0x1480 mm/page_alloc.c:3004
 folios_put_refs+0x9ff/0xb40 mm/swap.c:1008
 folio_batch_release include/linux/folio_batch.h:101 [inline]
 shmem_undo_range+0x52c/0x1660 mm/shmem.c:1149
 shmem_truncate_range mm/shmem.c:1277 [inline]
 shmem_evict_inode+0x289/0xae0 mm/shmem.c:1407
 evict+0x61e/0xb10 fs/inode.c:841
 __dentry_kill+0x1a2/0x690 fs/dcache.c:718
 finish_dput+0xc9/0x480 fs/dcache.c:927
 __fput+0x691/0xa60 fs/file_table.c:518
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3e3c75d60e
RSP: 002b:00007fffdb528c28 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000055557d46a500 RCX: 00007f3e3c75d60e
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fffdb528ccc R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000022b
R13: 00000000000927c0 R14: 000000000016c38a R15: 00007fffdb528d20
 </TASK>
task:syz.0.5589      state:R  running task     stack:25464 pid:25416 tgid:25415 ppid:16870  task_flags:0x400040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7188
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7369
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
 _raw_spin_unlock_irqrestore+0x74/0x80 kernel/locking/spinlock.c:198
 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline]
 lruvec_unlock_irqrestore include/linux/memcontrol.h:1492 [inline]
 folios_put_refs+0x8dd/0xb40 mm/swap.c:1000
 folio_batch_release include/linux/folio_batch.h:101 [inline]
 shmem_undo_range+0x52c/0x1660 mm/shmem.c:1149
 shmem_truncate_range mm/shmem.c:1277 [inline]
 shmem_evict_inode+0x289/0xae0 mm/shmem.c:1407
 evict+0x61e/0xb10 fs/inode.c:841
 __dentry_kill+0x1a2/0x690 fs/dcache.c:718
 finish_dput+0xc9/0x480 fs/dcache.c:927
 __fput+0x691/0xa60 fs/file_table.c:518
 fput_close_sync+0x11f/0x240 fs/file_table.c:615
 __do_sys_close fs/open.c:1507 [inline]
 __se_sys_close fs/open.c:1492 [inline]
 __x64_sys_close+0x7e/0x110 fs/open.c:1492
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f399cd5d60e
RSP: 002b:00007f399dc9bda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f399dc9c6c0 RCX: 00007f399cd5d60e
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f399dc9bee0 R14: 00007f399dc9bea0 R15: 00007f3992a00000
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g106909 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=34266
rcu: rcu_preempt kthread starved for 10505 jiffies! g106909 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:26784 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7188
 __schedule_loop kernel/sched/core.c:7267 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7282
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </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: 0 Comm: swapper/1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:rb_erase_linked+0x15c/0x190 lib/rbtree.c:462
Code: e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 8d e1 8d f6 4d 89 3f 48 83 c3 08 ba 10 00 00 00 48 89 ef 31 f6 e8 57 e3 8d f6 48 89 d8 <48> c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 71 e0 8d f6 48 83 3b
RSP: 0018:ffffc90000a08d48 EFLAGS: 00000002
RAX: ffff8880b8728420 RBX: ffff8880b8728420 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff88807bdfc328
RBP: ffff88807bdfc318 R08: ffff88807bdfc327 R09: ffff88807bdfc318
R10: dffffc0000000000 R11: ffffed100f7bf865 R12: 0000000000000000
R13: dffffc0000000000 R14: 1ffff1100f7bf863 R15: ffff88807bdfc300
FS:  0000000000000000(0000) GS:ffff888125395000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000bc5000 CR3: 0000000098ed2000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 timerqueue_linked_del include/linux/timerqueue.h:66 [inline]
 __remove_hrtimer+0xf7/0x3e0 kernel/time/hrtimer.c:1155
 __run_hrtimer kernel/time/hrtimer.c:1910 [inline]
 __hrtimer_run_queues+0x299/0xa20 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 7b 7e 02 e9 fe 8f 68 f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 b1 21 00 fb f4 <e9> d7 8f 68 f5 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000242
RAX: 00000000012c7e7f RBX: ffffffff819a815a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfa34f0 RDI: ffffffff8c28aa60
RBP: ffffc90000197f10 R08: ffff8880b87339db R09: 1ffff110170e673b
R10: dffffc0000000000 R11: ffffed10170e673c R12: 0000000000000001
R13: 1ffff11003b5c000 R14: 0000000000000001 R15: 1ffff11003b5c000
 arch_safe_halt arch/x86/kernel/process.c:766 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x36a/0x5f0 kernel/sched/idle.c:352
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x147
 </TASK>