syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=85d4/1/0x4000000000000000 softirq=48736/48736 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P12345/1:b..l P36/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=50313, q=155 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 12477 Comm: syz.5.1667 Not tainted 6.14.0-rc7-syzkaller-00205-g586de92313fc #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:19 [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+0x175/0xa30 kernel/locking/lockdep.c:5868
Code: f7 e8 cf 9c 89 00 48 c7 c0 10 77 08 94 49 39 06 0f 84 ee 04 00 00 4c 8d b4 24 b0 00 00 00 4c 89 f3 48 c1 eb 03 42 80 3c 3b 00 <74> 08 4c 89 f7 e8 91 9d 89 00 4c 89 6c 24 50 48 c7 84 24 b0 00 00
RSP: 0018:ffffc90000a28a40 EFLAGS: 00000046
RAX: ffffffff94087710 RBX: 1ffff9200014515e RCX: ffffffff819cfa80
RDX: 0000000000000000 RSI: ffffffff8c802cc0 RDI: ffffffff8c802c80
RBP: ffffc90000a28b70 R08: ffffffff903bd177 R09: 1ffffffff2077a2e
R10: dffffc0000000000 R11: fffffbfff2077a2f R12: 1ffff92000145154
R13: ffffffff84f4e395 R14: ffffc90000a28af0 R15: dffffc0000000000
FS:  00007f53857e56c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34010ff8 CR3: 00000000653de000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x79/0x140 kernel/locking/spinlock.c:194
 debug_object_deactivate+0x2d5/0x390 lib/debugobjects.c:888
 debug_hrtimer_deactivate kernel/time/hrtimer.c:460 [inline]
 debug_deactivate+0x1b/0x220 kernel/time/hrtimer.c:502
 __run_hrtimer kernel/time/hrtimer.c:1769 [inline]
 __hrtimer_run_queues+0x305/0xd30 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5252
Code: c9 50 e8 a9 2d 0c 00 48 83 c4 08 4c 89 f7 e8 fd 39 00 00 e9 de 04 00 00 4c 89 f7 e8 d0 50 73 0a e8 6b 08 39 00 fb 48 8b 5d c0 <48> 8d bb 08 16 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc
RSP: 0018:ffffc9000b8671c8 EFLAGS: 00000282
RAX: 11bef1e00c0c8800 RBX: ffff88807c428000 RCX: ffffffff9a61e903
RDX: dffffc0000000000 RSI: ffffffff8c2ab3a0 RDI: ffffffff8c802ce0
RBP: ffffc9000b867210 R08: ffffffff903bd177 R09: 1ffffffff2077a2e
R10: dffffc0000000000 R11: fffffbfff2077a2f R12: 1ffff110170e7ebe
R13: dffffc0000000000 R14: ffff8880b863e7c0 R15: ffff8880b873f5f0
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x18c4/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75
 unix_wait_for_peer+0x250/0x340 net/unix/af_unix.c:1526
 unix_dgram_sendmsg+0xc74/0x1df0 net/unix/af_unix.c:2128
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:733
 ____sys_sendmsg+0x53a/0x860 net/socket.c:2573
 ___sys_sendmsg net/socket.c:2627 [inline]
 __sys_sendmmsg+0x36a/0x720 net/socket.c:2716
 __do_sys_sendmmsg net/socket.c:2743 [inline]
 __se_sys_sendmmsg net/socket.c:2740 [inline]
 __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2740
 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: 0033:0x7f538498d169
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:00007f53857e5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f5384ba5fa0 RCX: 00007f538498d169
RDX: 0000000000000651 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f5384a0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5384ba5fa0 R15: 00007ffec5fafa38
 </TASK>
task:kworker/u8:2    state:R  running task     stack:20848 pid:36    tgid:36    ppid:2      task_flags:0x4208160 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7087
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:lock_release+0x658/0xa30 kernel/locking/lockdep.c:5876
Code: 3c 3b 00 74 08 4c 89 f7 e8 e5 97 89 00 f6 84 24 91 00 00 00 02 75 77 41 f7 c5 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 4b c7 44 27 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90000ac7980 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000158f42 RCX: ffffc90000ac7a03
RDX: 0000000000000002 RSI: ffffffff8c2ac600 RDI: ffffffff8c802ce0
RBP: ffffc90000ac7aa8 R08: ffffffff903bd177 R09: 1ffffffff2077a2e
R10: dffffc0000000000 R11: fffffbfff2077a2f R12: 1ffff92000158f3c
R13: 0000000000000246 R14: ffffc90000ac7a10 R15: dffffc0000000000
 rcu_lock_release include/linux/rcupdate.h:347 [inline]
 rcu_read_unlock include/linux/rcupdate.h:880 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0x28b/0x610 net/batman-adv/network-coding.c:719
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 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
 </TASK>
task:syz.2.1627      state:R  running task     stack:22072 pid:12345 tgid:12345 ppid:5827   task_flags:0x40064c flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7087
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:unwind_next_frame+0x5/0x22d0 arch/x86/kernel/unwind_orc.c:469
Code: 80 e1 07 80 c1 03 38 c1 7c 91 4c 89 f7 e8 33 63 b9 00 eb 87 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 81 ec 98 00 00 00 49 89 fd 49 bc 00
RSP: 0018:ffffc9000c246d10 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc9000c246d20 RCX: ffffffff919c1000
RDX: dffffc0000000000 RSI: ffffffff81ad6ad8 RDI: ffffc9000c246d20
RBP: ffffc9000c246db0 R08: 0000000000000000 R09: ffffc9000c246e10
R10: ffffc9000c246d70 R11: ffffffff81ad6ba0 R12: ffff888053d39e00
R13: ffffffff81ad6ba0 R14: ffffc9000c246e00 R15: 0000000000000000
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 save_stack+0xfb/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x76/0x430 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+0xe2f/0x18a0 mm/page_alloc.c:2707
 folios_put_refs+0x76c/0x860 mm/swap.c:994
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x593/0x1820 mm/shmem.c:1112
 shmem_truncate_range mm/shmem.c:1224 [inline]
 shmem_evict_inode+0x29b/0xa80 mm/shmem.c:1352
 evict+0x4e8/0x9a0 fs/inode.c:796
 __dentry_kill+0x20d/0x630 fs/dcache.c:643
 dput+0x19f/0x2b0 fs/dcache.c:885
 __fput+0x60b/0x9f0 fs/file_table.c:472
 task_work_run+0x24f/0x310 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xa2a/0x2940 kernel/exit.c:938
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x168c/0x1720 kernel/signal.c:3036
 arch_do_signal_or_restart+0x96/0x860 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+0x7e/0x250 kernel/entry/common.c:231
 exc_page_fault+0x590/0x8b0 arch/x86/mm/fault.c:1541
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f21fdc4e757
RSP: 002b:00007f21fbbd7120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f21fdd8d169
RDX: 00007f21fbbd7140 RSI: 00007f21fbbd7270 RDI: 000000000000000b
RBP: 00007f21fde0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f21fdfa6160 R15: 00007ffcaf636e88
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g50313 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=46283
rcu: rcu_preempt kthread starved for 10502 jiffies! g50313 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:25784 pid:18    tgid:18    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 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
 </TASK>