syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11413/1:b..l P6892/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=33709, q=232 ncpus=2)
task:syz-executor    state:R  running task     stack:24008 pid:6892  tgid:6892  ppid:6875   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x53a/0x20b0 arch/x86/kernel/unwind_orc.c:527
Code: e2 07 38 d0 7f 08 84 c0 0f 85 28 15 00 00 0f b6 41 05 83 e0 07 0f 84 53 fe ff ff 3c 01 0f 84 7b fe ff ff 4c 8d 41 04 4c 89 fe <48> b8 00 00 00 00 00 fc ff df 4c 89 c2 48 c1 ee 03 48 c1 ea 03 0f
RSP: 0018:ffffc9000404f808 EFLAGS: 00000202
RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff91b0df58
RDX: 0000000000000005 RSI: ffffffff91b0df5d RDI: ffffffff90fd81d4
RBP: ffffc9000404f8c0 R08: ffffffff91b0df5c R09: 00000000d72345cb
R10: 0000000000000002 R11: 0000000000083af9 R12: ffffc9000404f8c8
R13: ffffc9000404f878 R14: ffffc9000404f8ad R15: ffffffff91b0df5d
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 __call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3119
 slab_free_hook mm/slub.c:2504 [inline]
 slab_free mm/slub.c:6670 [inline]
 kmem_cache_free+0x171/0x770 mm/slub.c:6781
 sk_prot_free net/core/sock.c:2282 [inline]
 __sk_destruct+0x64c/0xbc0 net/core/sock.c:2384
 sk_destruct+0xc2/0xf0 net/core/sock.c:2412
 __sk_free+0xf4/0x3e0 net/core/sock.c:2423
 sk_free+0x6a/0x90 net/core/sock.c:2434
 sock_put include/net/sock.h:1998 [inline]
 tcp_close+0xd3/0x120 net/ipv4/tcp.c:3303
 inet_release+0xed/0x200 net/ipv4/af_inet.c:437
 inet6_release+0x4f/0x70 net/ipv6/af_inet6.c:487
 __sock_release+0xb3/0x270 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x402/0xb70 fs/file_table.c:468
 fput_close_sync+0x118/0x260 fs/file_table.c:573
 __do_sys_close fs/open.c:1573 [inline]
 __se_sys_close fs/open.c:1558 [inline]
 __x64_sys_close+0x8b/0x120 fs/open.c:1558
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffbe138e3aa
RSP: 002b:00007ffe8ccb67f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007ffbe138e3aa
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffe8ccb684c R08: 00007ffe8ccb613c R09: 0079746972756365
R10: 00007ffe8ccb61a0 R11: 0000000000000293 R12: 00000000000000c6
R13: 00000000000927c0 R14: 0000000000053e4d R15: 00007ffe8ccb68a0
 </TASK>
task:syz.1.1232      state:R  running task     stack:28136 pid:11413 tgid:11413 ppid:5805   task_flags:0x40004c flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7047
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 zap_pte_range mm/memory.c:1884 [inline]
 zap_pmd_range mm/memory.c:1946 [inline]
 zap_pud_range mm/memory.c:1975 [inline]
 zap_p4d_range mm/memory.c:1996 [inline]
 unmap_page_range+0x1047/0x43c0 mm/memory.c:2017
 unmap_single_vma+0x153/0x240 mm/memory.c:2059
 unmap_vmas+0x218/0x470 mm/memory.c:2101
 exit_mmap+0x1b0/0xb60 mm/mmap.c:1277
 __mmput+0x12a/0x410 kernel/fork.c:1173
 mmput+0x62/0x70 kernel/fork.c:1196
 exit_mm kernel/exit.c:581 [inline]
 do_exit+0x7d7/0x2bd0 kernel/exit.c:959
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1112
 __do_sys_exit_group kernel/exit.c:1123 [inline]
 __se_sys_exit_group kernel/exit.c:1121 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1121
 x64_sys_call+0x151c/0x1740 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f11f838f749
RSP: 002b:00007fff6d1ff9b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f11f838f749
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fff6d1ffa1c R08: 000000036d1ffaaf R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000126
R13: 00000000000927c0 R14: 0000000000053cd2 R15: 00007fff6d1ffa70
 </TASK>
rcu: rcu_preempt kthread starved for 10562 jiffies! g33709 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:28104 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 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 49 12 00 fb f4 <e9> cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6
RAX: 0000000000a00ded RBX: 0000000000000000 RCX: ffffffff8b7816d9
RDX: 0000000000000000 RSI: ffffffff8dacdf79 RDI: ffffffff8bf2b400
RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d
R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000
R13: ffffffff8e097b40 R14: ffffffff9088b6d0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30b13ff8 CR3: 0000000075caf000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x38d/0x510 kernel/sched/idle.c:332
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
 rest_init+0x16b/0x2b0 init/main.c:757
 start_kernel+0x3ef/0x4d0 init/main.c:1206
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x148
 </TASK>