[v6.1] INFO: rcu detected stall in alloc_fd

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 779f9571ac3e Linux 6.1.164
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1043b006580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=c32d067d5fef8065b0a7
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/d8bc7a0c33a8/disk-779f9571.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/870b0bf266c7/vmlinux-779f9571.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ce1e3301c41d/bzImage-779f9571.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c32d06...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2655 jiffies s: 68889 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 15028 Comm: syz.1.3337 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:125 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:132 [inline]
RIP: 0010:lock_release+0x584/0x920 kernel/locking/lockdep.c:5685
Code: ff ff ff 65 0f c1 05 db b2 9d 7e 83 f8 01 75 7f 43 c6 44 2f 04 00 48 c7 84 24 80 00 00 00 00 00 00 00 9c 8f 84 24 80 00 00 00 <f7> 84 24 80 00 00 00 00 02 00 00 43 c6 44 2f 04 f8 75 70 f7 44 24
RSP: 0018:ffffc90000007660 EFLAGS: 00000046
RAX: 0000000000000001 RBX: da2e616334457c0f RCX: 8664e1e393a97400
RDX: 0000000000000002 RSI: ffffffff8a8c23a0 RDI: ffffffff8adf0de0
RBP: ffffc90000007770 R08: ffffffff8e1fcd2f R09: 1ffffffff1c3f9a5
R10: dffffc0000000000 R11: fffffbfff1c3f9a6 R12: ffff88802c47c6b0
R13: dffffc0000000000 R14: ffff88802c47c650 R15: 1ffff92000000ed8
FS: 00007f1c41a006c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00001ffffffffec0 CR3: 000000005a5fd000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
rcu_lock_release include/linux/rcupdate.h:355 [inline]
rcu_read_unlock include/linux/rcupdate.h:824 [inline]
trace_call_bpf+0x5ca/0x6b0 kernel/trace/bpf_trace.c:137
perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:9997
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 92 31 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:ffffc90000007aa0 EFLAGS: 00000206
RAX: 8664e1e393a97400 RBX: 1ffff92000000f5c RCX: 8664e1e393a97400
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: ffffffff8adf0de0
RBP: ffffc90000007b90 R08: ffffffff90af525f R09: 1ffffffff215ea4b
R10: dffffc0000000000 R11: fffffbfff215ea4c R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3b900 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:823 [inline]
ieee80211_iterate_active_interfaces_atomic+0x156/0x170 net/mac80211/util.c:826
mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2147
__run_hrtimer kernel/time/hrtimer.c:1747 [inline]
__hrtimer_run_queues+0x560/0xd70 kernel/time/hrtimer.c:1811
hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828
handle_softirqs+0x2a1/0x930 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:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:219
Code: 8b 15 15 fa 7f 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 <48> 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39
RSP: 0018:ffffc9000c5cfcb8 EFLAGS: 00000246
RAX: ffffffff81e95e58 RBX: 0000000000000001 RCX: ffff88802c47bb80
RDX: 0000000000000002 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000c5cfdf8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520018b9fb0 R12: 1ffff920018b9fa4
R13: 000000000000000a R14: ffff88805a028c00 R15: dffffc0000000000
expand_files+0x128/0x800 fs/file.c:229
alloc_fd+0x218/0x630 fs/file.c:512
__sys_socketpair+0x64/0x540 net/socket.c:1709
__do_sys_socketpair net/socket.c:1785 [inline]
__se_sys_socketpair net/socket.c:1782 [inline]
__x64_sys_socketpair+0x97/0xb0 net/socket.c:1782
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: 0033:0x7f1c40b9c799
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:00007f1c41a00028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f1c40e15fa0 RCX: 00007f1c40b9c799
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 00007f1c40c32bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000001380 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1c40e16038 R14: 00007f1c40e15fa0 R15: 00007ffeac685908
</TASK>


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