[v5.15] INFO: rcu detected stall in tun_chr_close (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 91d48252ad4b Linux 5.15.202
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1279bbd6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=e5cae1bc08235555e8a0
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1f63ca11335d/disk-91d48252.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/85d7c8824423/vmlinux-91d48252.xz
kernel image: https://storage.googleapis.com/syzbot-assets/11897ccd5b62/bzImage-91d48252.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e5cae1...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-....: (1 GPs behind) idle=487/1/0x4000000000000002 softirq=8476/8477 fqs=2100
(detected by 1, t=10505 jiffies, g=9553, q=1347)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4867 Comm: syz.4.150 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:perf_swevent_put_recursion_context kernel/events/core.c:9750 [inline]
RIP: 0010:perf_tp_event+0xa72/0xbf0 kernel/events/core.c:10080
Code: c0 32 8a be 02 03 00 00 48 c7 c2 20 c1 32 8a e8 54 0d 19 08 e8 8f f2 cc ff 48 c7 c7 a0 ea 31 8c e8 53 ce 01 00 e8 de ee 23 08 <41> 89 c6 89 c3 bf 08 00 00 00 89 c6 e8 6d 9a e0 ff 41 83 fe 07 0f
RSP: 0018:ffffc90000007640 EFLAGS: 00000086
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 498e59ddccaf3b00
RDX: 0000000000000100 RSI: ffffffff8a79f960 RDI: ffffffff8a79f920
RBP: ffffc900000078c8 R08: ffffffff8d89e36f R09: 1ffffffff1b13c6d
R10: dffffc0000000000 R11: fffffbfff1b13c6e R12: ffff8880b9035250
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007feaf11806c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c346442 CR3: 000000001e7f2000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 12 f2 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007b00 EFLAGS: 00000206
RAX: 498e59ddccaf3b00 RBX: 1ffff92000000f64 RCX: 498e59ddccaf3b00
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980
RBP: ffffc90000007bd8 R08: ffffffff901d40cf R09: 1ffffffff203a819
R10: dffffc0000000000 R11: fffffbfff203a81a R12: ffffffff8c322f00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
ieee80211_iterate_active_interfaces_atomic+0x132/0x140 net/mac80211/util.c:831
mac80211_hwsim_beacon+0x9b/0x180 drivers/net/wireless/mac80211_hwsim.c:1865
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x4f2/0xb70 kernel/time/hrtimer.c:1749
hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
handle_softirqs+0x339/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:30 [inline]
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:52 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:178 [inline]
RIP: 0010:unwind_next_frame+0x1065/0x1d90 arch/x86/kernel/unwind_orc.c:448
Code: e8 3f 48 01 c8 48 83 e0 fe 4d 8d 74 45 00 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 27 49 63 06 <4c> 01 f0 49 8d 4e 04 48 39 e8 4c 0f 46 e9 49 8d 46 fc 4c 0f 47 e0
RSP: 0018:ffffc90002ebf508 EFLAGS: 00000246
RAX: fffffffffa1989a2 RBX: ffffc90002ebf5c8 RCX: dffffc0000000000
RDX: ffffffff8de7bf2c RSI: ffffffff8e7b12c2 RDI: ffffffff81350d2c
RBP: ffffffff88014a5e R08: 0000000000000001 R09: 0000000000000006
R10: dffffc0000000000 R11: fffff520005d7ec5 R12: ffffffff8de7bf2c
R13: ffffffff8de7bf2c R14: ffffffff8de7bf2c R15: ffffffff8de7bf2c
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
qdisc_destroy+0x115/0x390 net/sched/sch_generic.c:1028
qdisc_put net/sched/sch_generic.c:1047 [inline]
shutdown_scheduler_queue net/sched/sch_generic.c:1100 [inline]
netdev_for_each_tx_queue include/linux/netdevice.h:2388 [inline]
dev_shutdown+0x19f/0x710 net/sched/sch_generic.c:1408
unregister_netdevice_many+0xa2c/0x19f0 net/core/dev.c:11153
unregister_netdevice_queue+0x324/0x370 net/core/dev.c:11093
unregister_netdevice include/linux/netdevice.h:3029 [inline]
__tun_detach+0xd4a/0x1500 drivers/net/tun.c:686
tun_detach drivers/net/tun.c:702 [inline]
tun_chr_close+0x109/0x1b0 drivers/net/tun.c:3440
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7feaf2f47819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007feaf1180028 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007feaf31c1090 RCX: 00007feaf2f47819
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007feaf2fddc91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feaf31c1128 R14: 00007feaf31c1090 R15: 00007ffc82f36f28
</TASK>


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