syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=134c/1/0x4000000000000000 softirq=41824/41825 fqs=7
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P15496/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=35241, q=152 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 15624 Comm: syz.4.1373 Not tainted 6.13.0-rc4-syzkaller-00078-g059dd502b263 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:__lock_acquire+0xe98/0x3c40 kernel/locking/lockdep.c:5259
Code: 00 00 39 05 6a 14 a8 14 0f 82 82 12 00 00 ba 01 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5c 24 18 48 c7 04 03 00 00 00 00 <48> 8b 84 24 e8 00 00 00 65 48 2b 04 25 28 00 00 00 0f 85 93 22 00
RSP: 0018:ffffc90000a18b48 EFLAGS: 00000006
RAX: dffffc0000000000 RBX: 1ffff9200014317b RCX: 00000000d439196c
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffffffff96e53ae8
RBP: ffffffff96e572e8 R08: 0000000000000000 R09: fffffbfff2dca398
R10: ffffffff96e51cc7 R11: 0000000000000003 R12: ffff88807d0d0b51
R13: ffff88807d0d0000 R14: 0000000000000003 R15: ffff88807d0d0b58
FS:  00007fa2174036c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f70cff8 CR3: 000000004dc02000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 advance_sched+0x67f/0xc60 net/sched/sch_taprio.c:985
 __run_hrtimer kernel/time/hrtimer.c:1739 [inline]
 __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1803
 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1865
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x10f/0x400 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
 </IRQ>
 <TASK>
 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 a6 72 4a f6 48 89 df e8 ee f1 4a f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 e5 d6 3b f6 65 8b 05 a6 92 d7 74 85 c0 74 16 5b
RSP: 0018:ffffc900114cf5b8 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff88801b0850a8 RCX: 1ffffffff2dcae69
RDX: 0000000000000000 RSI: ffffffff8b6cd9e0 RDI: ffffffff8bd1eda0
RBP: 0000000000000283 R08: 0000000000000001 R09: fffffbfff2dca399
R10: ffffffff96e51ccf R11: 0000000000000005 R12: 0000000000200080
R13: 0000000000000000 R14: ffff88801b085070 R15: ffff888025274f00
 __setup_irq+0x10cd/0x1f00 kernel/irq/manage.c:1824
 request_threaded_irq+0x2b4/0x3e0 kernel/irq/manage.c:2208
 request_irq include/linux/interrupt.h:172 [inline]
 serial_link_irq_chain drivers/tty/serial/8250/8250_core.c:169 [inline]
 univ8250_setup_irq+0x547/0x6a0 drivers/tty/serial/8250/8250_core.c:292
 serial8250_do_startup+0x856/0x3a90 drivers/tty/serial/8250/8250_port.c:2320
 serial8250_startup+0x62/0x80 drivers/tty/serial/8250/8250_port.c:2478
 uart_port_startup drivers/tty/serial/serial_core.c:323 [inline]
 uart_startup+0x50f/0x1340 drivers/tty/serial/serial_core.c:367
 uart_port_activate+0xe8/0x190 drivers/tty/serial/serial_core.c:2010
 tty_port_open+0x153/0x1f0 drivers/tty/tty_port.c:784
 uart_open+0x41/0x60 drivers/tty/serial/serial_core.c:1990
 tty_open+0x3dd/0xf80 drivers/tty/tty_io.c:2146
 chrdev_open+0x237/0x6a0 fs/char_dev.c:414
 do_dentry_open+0xf59/0x1ea0 fs/open.c:945
 vfs_open+0x82/0x3f0 fs/open.c:1075
 do_open fs/namei.c:3828 [inline]
 path_openat+0x1e6a/0x2d60 fs/namei.c:3987
 do_filp_open+0x20c/0x470 fs/namei.c:4014
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1402
 do_sys_open fs/open.c:1417 [inline]
 __do_sys_openat fs/open.c:1433 [inline]
 __se_sys_openat fs/open.c:1428 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1428
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa216585d29
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:00007fa217403038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa216776080 RCX: 00007fa216585d29
RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c
RBP: 00007fa216601b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa216776080 R15: 00007fffff2a3048
 </TASK>
task:syz.3.1341      state:R  running task     stack:23648 pid:15496 tgid:15496 ppid:5815   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0xe58/0x5ad0 kernel/sched/core.c:6756
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6935
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 unwind_next_frame+0x1776/0x20c0 arch/x86/kernel/unwind_orc.c:672
 arch_stack_walk+0x95/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122
 save_stack+0x162/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x8d/0x400 mm/page_owner.c:297
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_folios+0xa7b/0x14f0 mm/page_alloc.c:2706
 folios_put_refs+0x587/0x7b0 mm/swap.c:962
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x586/0x1170 mm/shmem.c:1044
 shmem_truncate_range mm/shmem.c:1156 [inline]
 shmem_evict_inode+0x3a3/0xba0 mm/shmem.c:1284
 evict+0x409/0x960 fs/inode.c:796
 iput_final fs/inode.c:1946 [inline]
 iput fs/inode.c:1972 [inline]
 iput+0x52a/0x890 fs/inode.c:1958
 dentry_unlink_inode+0x29c/0x480 fs/dcache.c:422
 __dentry_kill+0x1d0/0x600 fs/dcache.c:625
 dput.part.0+0x4b1/0x9b0 fs/dcache.c:867
 dput+0x1f/0x30 fs/dcache.c:857
 __fput+0x515/0xb60 fs/file_table.c:458
 task_work_run+0x14e/0x250 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xad8/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x24ed/0x26c0 kernel/signal.c:3017
 arch_do_signal_or_restart+0x90/0x7e0 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]
 irqentry_exit_to_user_mode+0x13f/0x280 kernel/entry/common.c:231
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7ffb3dd85d31
RSP: 002b:0000000000000010 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007ffb3df75fa0 RCX: 00007ffb3dd85d29
RDX: 00000000200000c0 RSI: 0000000000000010 RDI: 0000000008001000
RBP: 00007ffb3de01b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ffb3df75fa0 R15: 00007ffcb50ed188
 </TASK>
rcu: rcu_preempt kthread starved for 10465 jiffies! g35241 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:27488 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0xe58/0x5ad0 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6848
 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045
 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 866 Comm: kworker/0:2 Not tainted 6.13.0-rc4-syzkaller-00078-g059dd502b263 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events fqdir_free_fn
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_single+0x1d7/0x580 kernel/smp.c:679
Code: af fa ff ff 41 89 c5 0f 1f 44 00 00 e8 42 f4 0b 00 eb 07 e8 3b f4 0b 00 f3 90 8b 5c 24 48 31 ff 83 e3 01 89 de e8 69 f6 0b 00 <85> db 75 e5 e8 20 f4 0b 00 e8 1b f4 0b 00 bf 01 00 00 00 e8 a1 fb
RSP: 0018:ffffc90003a87b20 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff818e2187
RDX: ffff88802584a440 RSI: 0000000000000000 RDI: 0000000000000005
RBP: ffffc90003a87c00 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000003 R12: 1ffff92000750f68
R13: 0000000000000000 R14: 0000000000000001 R15: ffff8880b873fb80
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f782e044e1e CR3: 000000002a806000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 rcu_barrier+0x28d/0x700 kernel/rcu/tree.c:4617
 fqdir_free_fn+0x32/0x130 net/ipv4/inet_fragment.c:167
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>