[v5.15] INFO: rcu detected stall in fib_nl_newrule (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: eceeec79dbc6 Linux 5.15.210
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=158b6bd2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6a0cae3abafc69
dashboard link: https://syzkaller.appspot.com/bug?extid=ca5bf767acc19b77a7de
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0843b8663fe3/disk-eceeec79.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/232e17f9e226/vmlinux-eceeec79.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c70c224634e9/bzImage-eceeec79.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ca5bf7...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-....: (28 ticks this GP) idle=587/1/0x4000000000000002 softirq=74529/74531 fqs=2103
(detected by 1, t=10503 jiffies, g=78293, q=1311)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 22988 Comm: syz.3.6811 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:irq_work_single kernel/irq_work.c:155 [inline]
RIP: 0010:irq_work_run_list+0x1c3/0x340 kernel/irq_work.c:177
Code: 48 89 54 24 08 0f 85 e8 00 00 00 c7 02 01 00 00 00 49 8d 7e 10 48 89 f8 48 c1 e8 03 80 3c 30 00 74 05 e8 90 3b 39 00 4c 89 f7 <41> ff 56 10 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 0f
RSP: 0018:ffffc90000007940 EFLAGS: 00000046
RAX: 1ffff11017207640 RBX: ffff8880b903b1f8 RCX: ffff88802ab05940
RDX: ffff88802ab06418 RSI: dffffc0000000000 RDI: ffff8880b903b1f0
RBP: ffffc900000079f8 R08: ffff8880b903b1fb R09: 1ffff1101720763f
R10: dffffc0000000000 R11: ffffed1017207640 R12: 1ffff11005560c83
R13: 0000000000000022 R14: ffff8880b903b1f0 R15: 0000000000000023
FS: 00007fb88a0066c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000340 CR3: 0000000060572000 CR4: 00000000003506f0
DR0: 0000000000000004 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
irq_work_run+0x63/0xe0 kernel/irq_work.c:186
__sysvec_irq_work+0x98/0x240 arch/x86/kernel/irq_work.c:22
instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
sysvec_irq_work+0x4a/0xc0 arch/x86/kernel/irq_work.c:17
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 c2 22 9d 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: 40daf6fe94b6c800 RBX: 1ffff92000000f64 RCX: 40daf6fe94b6c800
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a79c980
RBP: ffffc90000007bd8 R08: ffffffff901cb0d7 R09: 1ffffffff203961a
R10: dffffc0000000000 R11: fffffbfff203961b R12: ffffffff8c323400
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+0x4ea/0xb60 kernel/time/hrtimer.c:1749
hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
handle_softirqs+0x336/0x830 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:lock_release+0x5a4/0x8a0 kernel/locking/lockdep.c:5647
Code: 80 00 00 00 f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 2c 04 f8 75 6f 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 2c 00 00 00 00 43 c7 44 2c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900030beac0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 10e42062edc6c1cc RCX: 40daf6fe94b6c800
RDX: 0000000000000002 RSI: ffffffff8a2b3e80 RDI: ffffffff8a79c980
RBP: ffffc900030bebd0 R08: ffffffff8d89e06f R09: 1ffffffff1b13c0d
R10: dffffc0000000000 R11: fffffbfff1b13c0e R12: 1ffff92000617d64
R13: dffffc0000000000 R14: ffff88802ab06420 R15: 0000000000000246
rcu_read_unlock include/linux/rcupdate.h:773 [inline]
BPF_PROG_RUN_ARRAY include/linux/bpf.h:1444 [inline]
trace_call_bpf+0x4fe/0x5b0 kernel/trace/bpf_trace.c:127
perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10016
perf_trace_lock_acquire+0x341/0x3f0 include/trace/events/lock.h:13
trace_lock_acquire include/trace/events/lock.h:13 [inline]
lock_acquire+0x3d7/0x400 kernel/locking/lockdep.c:5594
fs_reclaim_acquire+0x91/0x100 mm/page_alloc.c:4597
might_alloc include/linux/sched/mm.h:206 [inline]
slab_pre_alloc_hook+0x20/0xc0 mm/slab.h:492
slab_alloc_node mm/slub.c:3139 [inline]
slab_alloc mm/slub.c:3233 [inline]
kmem_cache_alloc+0x3d/0x280 mm/slub.c:3238
fib_trie_unmerge+0x266/0xce0 net/ipv4/fib_trie.c:1896
fib_unmerge+0xbc/0x350 net/ipv4/fib_frontend.c:160
fib4_rule_configure+0xe0/0xb00 net/ipv4/fib_rules.c:239
fib_nl_newrule+0x131a/0x1e00 net/core/fib_rules.c:793
rtnetlink_rcv_msg+0x82c/0xf00 net/core/rtnetlink.c:5688
netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2512
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1923
sock_sendmsg_nosec net/socket.c:706 [inline]
__sock_sendmsg net/socket.c:718 [inline]
____sys_sendmsg+0x5be/0x8f0 net/socket.c:2446
___sys_sendmsg+0x236/0x2e0 net/socket.c:2500
__sys_sendmsg net/socket.c:2529 [inline]
__do_sys_sendmsg net/socket.c:2538 [inline]
__se_sys_sendmsg+0x1b7/0x2a0 net/socket.c:2536
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb88bdace59
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:00007fb88a006028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb88c025fa0 RCX: 00007fb88bdace59
RDX: 0000000000000000 RSI: 0000200000000940 RDI: 0000000000000007
RBP: 00007fb88be42e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb88c026038 R14: 00007fb88c025fa0 R15: 00007ffe8a4cc138
</TASK>


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