[v6.1] INFO: rcu detected stall in rtnl_newlink (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8e6e2188d949 Linux 6.1.157
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14225e7c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7eb38bd5021fec61
dashboard link: https://syzkaller.appspot.com/bug?extid=e5c69c6f95c5b9d23c39
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/18845d0cccdc/disk-8e6e2188.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a65d29c3a1da/vmlinux-8e6e2188.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f8120e905229/bzImage-8e6e2188.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e5c69c...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2675 jiffies s: 116637 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: 23707 Comm: syz.3.5347 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:lockdep_hardirqs_on_prepare+0xe0/0x760 kernel/locking/lockdep.c:4296
Code: 48 c7 c0 40 91 be 96 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 0b 05 00 00 83 3d 8c cf 5b 15 00 75 6c 48 c7 44 24 40 00 00 00 00 9c <8f> 44 24 40 f6 44 24 41 02 0f 85 87 03 00 00 48 c7 c0 40 91 be 96
RSP: 0018:ffffc900001e0a98 EFLAGS: 00000046
RAX: 0000000000000004 RBX: 1ffff9200003c158 RCX: ffffffff96be9103
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff8cb719a0
RBP: ffffc900001e0b60 R08: dffffc0000000000 R09: ffffed10171e6afa
R10: ffffed10171e6afa R11: 1ffff110171e6af9 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007ff30e9f66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2dd1fff8 CR3: 000000005cc3a000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600
Call Trace:
<IRQ>
trace_hardirqs_on+0x34/0x40 kernel/trace/trace_preemptirq.c:49
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x84/0x500 kernel/rcu/tree_plugin.h:685
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 0d 93 96 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001e0c20 EFLAGS: 00000206
RAX: 195394e328b38700 RBX: 1ffff9200003c18c RCX: 195394e328b38700
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: ffffffff8adef3a0
RBP: ffffc900001e0d08 R08: dffffc0000000000 R09: fffffbfff215c450
R10: fffffbfff215c450 R11: 1ffffffff215c44f R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:823 [inline]
rebalance_domains+0x89c/0x9d0 kernel/sched/fair.c:11044
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x12f/0x220 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:call_rcu+0x6e0/0x980 kernel/rcu/tree.c:2886
Code: 00 9c 8f 84 24 a0 00 00 00 f6 84 24 a1 00 00 00 02 75 54 f7 44 24 58 00 02 00 00 74 01 fb 48 c7 84 24 80 00 00 00 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 66 43 c7 44 25 09 00 00 43 c6 44 25 0b
RSP: 0018:ffffc9000d7e62e0 EFLAGS: 00000206
RAX: 195394e328b38700 RBX: ffff88801b7d6780 RCX: 195394e328b38700
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: ffffffff8adef3a0
RBP: ffffc9000d7e6410 R08: dffffc0000000000 R09: fffffbfff215c450
R10: fffffbfff215c450 R11: 1ffffffff215c44f R12: dffffc0000000000
R13: 1ffff92001afcc6c R14: 1ffff110171e774d R15: 000000000000000d
collapse net/ipv4/fib_trie.c:703 [inline]
resize+0x24a9/0x26e0 net/ipv4/fib_trie.c:906
trie_rebalance net/ipv4/fib_trie.c:1106 [inline]
fib_remove_alias+0x322/0x480 net/ipv4/fib_trie.c:1650
fib_table_delete+0xcfe/0xf80 net/ipv4/fib_trie.c:1752
fib_magic+0x2e1/0x390 net/ipv4/fib_frontend.c:1120
fib_del_ifaddr+0xfdf/0x1480 net/ipv4/fib_frontend.c:1322
fib_inetaddr_event+0xb7/0x1c0 net/ipv4/fib_frontend.c:1462
notifier_call_chain kernel/notifier.c:87 [inline]
blocking_notifier_call_chain+0x103/0x1b0 kernel/notifier.c:382
__inet_del_ifa+0x879/0x1020 net/ipv4/devinet.c:445
inet_del_ifa net/ipv4/devinet.c:482 [inline]
inetdev_destroy net/ipv4/devinet.c:323 [inline]
inetdev_event+0x5b7/0x1410 net/ipv4/devinet.c:1615
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
call_netdevice_notifiers_mtu net/core/dev.c:2076 [inline]
dev_set_mtu_ext+0x432/0x610 net/core/dev.c:8780
do_setlink+0x8ee/0x3c40 net/core/rtnetlink.c:2796
__rtnl_newlink net/core/rtnetlink.c:3608 [inline]
rtnl_newlink+0x17d6/0x1ff0 net/core/rtnetlink.c:3655
rtnetlink_rcv_msg+0x79b/0xed0 net/core/rtnetlink.c:6153
netlink_rcv_skb+0x1de/0x420 net/netlink/af_netlink.c:2511
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x74d/0x8d0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x89e/0xbc0 net/netlink/af_netlink.c:1872
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
____sys_sendmsg+0x59b/0x970 net/socket.c:2519
___sys_sendmsg+0x21c/0x290 net/socket.c:2573
__sys_sendmsg net/socket.c:2602 [inline]
__do_sys_sendmsg net/socket.c:2611 [inline]
__se_sys_sendmsg+0x19e/0x270 net/socket.c:2609
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff31078efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff30e9f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff3109e5fa0 RCX: 00007ff31078efc9
RDX: 0000000020000004 RSI: 0000200000000480 RDI: 000000000000000e
RBP: 00007ff310811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff3109e6038 R14: 00007ff3109e5fa0 R15: 00007ffdcab65018
</TASK>


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