syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5819/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=35249, q=310 ncpus=2)
task:syz-executor    state:R  running task     stack:23272 pid:5819  tgid:5819  ppid:5805   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:on_stack arch/x86/include/asm/stacktrace.h:55 [inline]
RIP: 0010:unwind_next_frame+0x1632/0x20a0 arch/x86/kernel/unwind_orc.c:665
Code: fc ff df 48 8b 14 24 48 c1 ea 03 80 3c 02 00 0f 85 37 05 00 00 49 8d 7d 08 49 8b 5d 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa <48> c1 ea 03 80 3c 02 00 0f 85 0a 05 00 00 49 8d 7d 10 49 8b 6d 08
RSP: 0018:ffffc9000428f868 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffc9000428fd00 RCX: ffffc90004290000
RDX: ffffc9000428f8e0 RSI: ffffc9000428fcd0 RDI: ffffc9000428f8e0
RBP: 0000000000000000 R08: 0000000000000001 R09: 000000004f8bb13e
R10: 0000000000000002 R11: 0000000000083c59 R12: ffffc9000428f928
R13: ffffc9000428f8d8 R14: ffffc9000428fd00 R15: ffffc9000428f90c
 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:56
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 slab_free_hook mm/slub.c:2501 [inline]
 slab_free mm/slub.c:6668 [inline]
 kmem_cache_free+0x15e/0x770 mm/slub.c:6779
 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
 __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: 0033:0x7f079a18e3aa
RSP: 002b:00007ffdb099bf20 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f079a18e3aa
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffdb099bf7c R08: 00007ffdb099b86c R09: 0079746972756365
R10: 00007ffdb099b8d0 R11: 0000000000000293 R12: 0000000000000110
R13: 00000000000927c0 R14: 0000000000072dfa R15: 00007ffdb099bfd0
 </TASK>
rcu: rcu_preempt kthread starved for 10535 jiffies! g35249 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:28064 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 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: 36 60 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 e9 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:ffffc90000197de8 EFLAGS: 000002c6
RAX: 0000000001696399 RBX: 0000000000000001 RCX: ffffffff8b7776d9
RDX: 0000000000000000 RSI: ffffffff8dacb6cd RDI: ffffffff8bf2a580
RBP: ffffed1003b56498 R08: 0000000000000001 R09: ffffed10170a673d
R10: ffff8880b85339eb R11: ffff88801dab2ff0 R12: 0000000000000001
R13: ffff88801dab24c0 R14: ffffffff90887cd0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881249fd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000002f000 CR3: 0000000061424000 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
 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x148
 </TASK>