[v5.15] INFO: rcu detected stall in inet_diag_dump_compat

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 43bb85222e53 Linux 5.15.193
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=109256e2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=67eb83593d1eee4cfcf6
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/0bc183664ae8/disk-43bb8522.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0fc2f6618934/vmlinux-43bb8522.xz
kernel image: https://storage.googleapis.com/syzbot-assets/af70b3957f4c/bzImage-43bb8522.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+67eb83...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-....: (1 GPs behind) idle=7ef/1/0x4000000000000002 softirq=43719/43720 fqs=2105
(detected by 1, t=10502 jiffies, g=62305, q=1242)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 14901 Comm: syz.2.3748 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__kasan_check_write+0x2/0x10 mm/kasan/shadow.c:37
Code: 0a 48 c7 c7 b5 97 a2 8b 48 89 de e8 48 3a e2 07 31 ed eb d7 00 00 cc cc 89 f6 48 8b 0c 24 31 d2 e9 43 ef ff ff 0f 1f 00 89 f6 <48> 8b 0c 24 ba 01 00 00 00 e9 30 ef ff ff 55 41 56 53 48 89 d3 89
RSP: 0018:ffffc90000007018 EFLAGS: 00000046
RAX: 0000000000000101 RBX: 1ffff92000000e08 RCX: dffffc0000000000
RDX: 0000000000000100 RSI: 0000000000000008 RDI: ffff888021010000
RBP: ffffc90000007100 R08: dffffc0000000000 R09: fffffbfff1ad323e
R10: fffffbfff1ad323e R11: 1ffffffff1ad323d R12: ffffffff8c120b00
R13: 0000000000000000 R14: 0000000000000046 R15: ffff888021010000
FS: 00007f8c0f6d26c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3320eff8 CR3: 0000000074b1c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
instrument_atomic_write include/linux/instrumented.h:86 [inline]
set_bit include/asm-generic/bitops/instrumented-atomic.h:28 [inline]
set_ti_thread_flag include/linux/thread_info.h:89 [inline]
set_tsk_thread_flag include/linux/sched.h:1968 [inline]
set_tsk_need_resched include/linux/sched.h:1999 [inline]
rcu_read_unlock_special+0x25f/0x480 kernel/rcu/tree_plugin.h:659
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:771 [inline]
__perf_event_output kernel/events/core.c:7813 [inline]
perf_event_output_forward+0x216/0x280 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2be/0x380 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+0x84/0x480 kernel/rcu/tree_plugin.h:674
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 ad 13 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900000077a0 EFLAGS: 00000206
RAX: 15f55f01db57c100 RBX: 1ffff92000000ef8 RCX: 15f55f01db57c100
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a480
RBP: ffffc90000007880 R08: dffffc0000000000 R09: fffffbfff1ff782b
R10: fffffbfff1ff782b R11: 1ffffffff1ff782a R12: ffffffff8c120b00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:771 [inline]
netif_receive_skb_list_internal+0x93a/0xb90 net/core/dev.c:5760
gro_normal_list net/core/dev.c:5913 [inline]
napi_complete_done+0x37d/0x830 net/core/dev.c:6651
virtqueue_napi_complete drivers/net/virtio_net.c:357 [inline]
virtnet_poll+0x912/0xef0 drivers/net/virtio_net.c:1624
__napi_poll+0xc0/0x430 net/core/dev.c:7075
napi_poll net/core/dev.c:7142 [inline]
net_rx_action+0x4a8/0x9c0 net/core/dev.c:7232
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 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:inet_diag_dump_icsk+0x80c/0x13c0 net/ipv4/inet_diag.c:1089
Code: b6 04 28 84 c0 0f 85 25 0a 00 00 48 8b 44 24 68 8b 18 23 5c 24 28 ba 80 00 00 00 48 8d bc 24 10 01 00 00 31 f6 e8 24 a6 42 f9 <ba> 40 00 00 00 48 8d bc 24 b0 01 00 00 31 f6 e8 10 a6 42 f9 4c 89
RSP: 0018:ffffc900034bf020 EFLAGS: 00000202
RAX: ffffc900034bf130 RBX: 000000000000006f RCX: 0000000000000000
RDX: 0000000000000080 RSI: 0000000000000000 RDI: ffffc900034bf1b0
RBP: ffffc900034bf2a0 R08: dffffc0000000000 R09: ffffc900034bf130
R10: fffff52000697e36 R11: 1ffff92000697e26 R12: ffff88807cad65f0
R13: dffffc0000000000 R14: ffffc9000194b778 R15: ffff888019593500
__inet_diag_dump+0x1f6/0x380 net/ipv4/inet_diag.c:1179
inet_diag_dump_compat+0x161/0x200 net/ipv4/inet_diag.c:1288
netlink_dump+0x676/0xcd0 net/netlink/af_netlink.c:2283
__netlink_dump_start+0x523/0x700 net/netlink/af_netlink.c:2386
netlink_dump_start include/linux/netlink.h:258 [inline]
inet_diag_rcv_msg_compat+0x1e9/0x3c0 net/ipv4/inet_diag.c:1323
sock_diag_rcv_msg+0x164/0x3e0 net/core/sock_diag.c:-1
netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507
sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
__sys_sendmsg net/socket.c:2519 [inline]
__do_sys_sendmsg net/socket.c:2528 [inline]
__se_sys_sendmsg+0x190/0x250 net/socket.c:2526
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: 0033:0x7f8c1146aec9
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:00007f8c0f6d2038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8c116c1fa0 RCX: 00007f8c1146aec9
RDX: 0000000008004000 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f8c114edf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8c116c2038 R14: 00007f8c116c1fa0 R15: 00007fff88413428
</TASK>


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