[v6.1] INFO: rcu detected stall in dev_ioctl (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1708bdb9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=2b4c5bcbbc71f74d6935
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6980f72dc28a/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b6cadb2b40be/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cdec5b077b58/bzImage-fb28aa72.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2b4c5b...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2688 jiffies s: 4005 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4788 Comm: syz.0.109 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:202 [inline]
RIP: 0010:arch_atomic_fetch_or arch/x86/include/asm/atomic.h:242 [inline]
RIP: 0010:atomic_fetch_or include/linux/atomic/atomic-instrumented.h:407 [inline]
RIP: 0010:irq_work_claim kernel/irq_work.c:59 [inline]
RIP: 0010:irq_work_queue_on+0xd1/0x260 kernel/irq_work.c:137
Code: dd 44 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 3e 01 00 00 45 8b 37 44 89 f1 83 c9 23 31 f6 44 89 f0 f0 41 0f b1 0f <41> 89 c4 41 0f 94 c5 40 0f 94 c6 bf 02 00 00 00 e8 da b0 f3 ff 45
RSP: 0018:ffffc900001e02c8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8880b8f3bbf0 RCX: 0000000000000023
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8880b8f3bbf8
RBP: 0000000000000001 R08: ffff8880b8f3bbfb R09: 1ffff110171e777f
R10: dffffc0000000000 R11: ffffed10171e7780 R12: dffffc0000000000
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8f3bbf8
FS: 00007fc27d7c96c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000cf3d CR3: 00000000298f0000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
rcu_read_unlock_special+0x3c9/0x510 kernel/rcu/tree_plugin.h:678
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:823 [inline]
trace_call_bpf+0x5bb/0x6b0 kernel/trace/bpf_trace.c:137
perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10027
perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
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 a2 7c 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900001e0760 EFLAGS: 00000206
RAX: eb911fa7ad44f500 RBX: 1ffff9200003c0f4 RCX: eb911fa7ad44f500
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adf5de0
RBP: ffffc900001e0860 R08: ffffffff90b10337 R09: 1ffffffff2162066
R10: dffffc0000000000 R11: fffffbfff2162067 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3bb00 R15: 0000000000000002
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:823 [inline]
ndisc_send_skb+0xdc2/0x1520 net/ipv6/ndisc.c:521
addrconf_rs_timer+0x367/0x640 net/ipv6/addrconf.c:3986
call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x56c/0x810 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x291/0x910 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 3f 89 1e f7 65 8b 05 b0 3a c8 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9000c57f580 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: eb911fa7ad44f500
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: ffffc9000c57f600 R08: ffffffff90b10247 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: dffffc0000000000
R13: ffff8881436cce00 R14: ffffffff8cbebfa0 R15: 1ffff920018afeb0
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
pcpu_alloc+0xb47/0x16b0 mm/percpu.c:1850
qdisc_alloc+0x422/0xa40 net/sched/sch_generic.c:968
qdisc_create_dflt+0x5f/0x490 net/sched/sch_generic.c:1012
mq_init+0x2c3/0x650 net/sched/sch_mq.c:90
qdisc_create_dflt+0x11a/0x490 net/sched/sch_generic.c:1019
attach_default_qdiscs net/sched/sch_generic.c:1199 [inline]
dev_activate+0x1dc/0x1150 net/sched/sch_generic.c:1253
__dev_open+0x343/0x430 net/core/dev.c:1510
__dev_change_flags+0x1e4/0x6a0 net/core/dev.c:8676
dev_change_flags+0x78/0x1a0 net/core/dev.c:8748
dev_ifsioc+0x130/0xd50 net/core/dev_ioctl.c:326
dev_ioctl+0x55e/0xe80 net/core/dev_ioctl.c:572
sock_do_ioctl+0x245/0x320 net/socket.c:1216
sock_ioctl+0x48a/0x700 net/socket.c:1321
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc27c99e019
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:00007fc27d7c9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc27cc25fa0 RCX: 00007fc27c99e019
RDX: 0000200000000080 RSI: 0000000000008914 RDI: 000000000000000d
RBP: 00007fc27ca3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc27cc26038 R14: 00007fc27cc25fa0 R15: 00007ffd2f7de3c8
</TASK>


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