[v6.1] INFO: rcu detected stall in rtnl_setlink
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syzbot
Jun 13, 2026, 2:38:37 PM (12 hours ago) Jun 13
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 228da13e907e Linux 6.1.175
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1782f3d2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4dd3c1715f0a309b
dashboard link: https://syzkaller.appspot.com/bug?extid=6c98b89b805fbe7f4ad4
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/894d01ce6736/disk-228da13e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2a4cec18e217/vmlinux-228da13e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/32550387ebe8/bzImage-228da13e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6c98b8...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2652 jiffies s: 62897 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: 19703 Comm: syz.5.4965 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5400 [inline]
RIP: 0010:lock_is_held_type+0xb4/0x190 kernel/locking/lockdep.c:5705
Code: df 49 81 c7 e0 0a 00 00 45 31 e4 49 83 fc 31 73 24 4c 89 ff 4c 89 f6 e8 2a 02 00 00 85 c0 75 2a 49 ff c4 48 63 83 d8 0a 00 00 <49> 83 c7 28 49 39 c4 7c d8 eb 11 48 c7 c7 60 c1 9f 8c 4c 89 e6 e8
RSP: 0018:ffffc900001e0758 EFLAGS: 00000002
RAX: 0000000000000004 RBX: ffff88802b729e00 RCX: 0000000000000000
RDX: ffff88802b729e00 RSI: ffffffff8cb2de60 RDI: ffff88802b72a8e0
RBP: 00000000ffffffff R08: dffffc0000000000 R09: 1ffffffff215fe48
R10: dffffc0000000000 R11: fffffbfff215fe49 R12: 0000000000000001
R13: 0000000000000046 R14: ffffffff8cb2de60 R15: ffff88802b72a8e0
FS: 00007f3d7e9136c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb214017dac CR3: 00000000827fc000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
trace_call_bpf+0x19e/0x6b0 kernel/trace/bpf_trace.c:135
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 82 30 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:ffffc900001e0ac0 EFLAGS: 00000206
RAX: 669f99cbb41e3a00 RBX: 1ffff9200003c160 RCX: 669f99cbb41e3a00
RDX: dffffc0000000000 RSI: ffffffff8a8c1aa0 RDI: ffffffff8adf2060
RBP: ffffc900001e0bb0 R08: ffffffff90aff24f R09: 1ffffffff215fe49
R10: dffffc0000000000 R11: fffffbfff215fe4a 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]
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:1751 [inline]
__hrtimer_run_queues+0x54a/0xd50 kernel/time/hrtimer.c:1815
hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1832
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:__rcu_read_unlock+0x65/0xd0 kernel/rcu/tree_plugin.h:433
Code: 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 75 5f 41 83 3e 00 75 20 43 0f b6 04 3c 84 c0 75 3a 8b 03 3d 00 00 00 40 73 0a <5b> 41 5c 41 5d 41 5e 41 5f c3 0f 0b eb f2 e8 58 00 00 00 eb d9 89
RSP: 0018:ffffc900033b6480 EFLAGS: 00000287
RAX: 0000000000000000 RBX: ffff88802b72a23c RCX: 0000000000080000
RDX: ffffc90013644000 RSI: 00000000000209bd RDI: ffff88802b729e00
RBP: 0000000000000000 R08: dffffc0000000000 R09: 1ffffffff215fe48
R10: dffffc0000000000 R11: fffffbfff215fe49 R12: 1ffff110056e5447
R13: dffffc0000000000 R14: ffff88802b72a240 R15: dffffc0000000000
rcu_read_unlock include/linux/rcupdate.h:823 [inline]
is_bpf_text_address+0x27a/0x2a0 kernel/bpf/core.c:737
kernel_text_address+0x9c/0xd0 kernel/extable.c:125
__kernel_text_address+0x9/0x30 kernel/extable.c:79
unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slab_common.c:936 [inline]
__kmalloc_node_track_caller+0xae/0x230 mm/slab_common.c:956
kmalloc_reserve net/core/skbuff.c:446 [inline]
pskb_expand_head+0x1a6/0x12a0 net/core/skbuff.c:1849
netlink_trim+0x180/0x220 net/netlink/af_netlink.c:1299
netlink_broadcast+0x75/0x10d0 net/netlink/af_netlink.c:1500
nlmsg_multicast include/net/netlink.h:1078 [inline]
nlmsg_notify+0xe7/0x1a0 net/netlink/af_netlink.c:2554
__dev_notify_flags+0xef/0x310 net/core/dev.c:8711
dev_change_flags+0xe4/0x1a0 net/core/dev.c:8753
do_setlink+0xba1/0x3e60 net/core/rtnetlink.c:2837
rtnl_setlink+0x37e/0x510 net/core/rtnetlink.c:3128
rtnetlink_rcv_msg+0x87c/0xfc0 net/core/rtnetlink.c:6158
netlink_rcv_skb+0x1fb/0x450 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+0x8ad/0xbd0 net/netlink/af_netlink.c:1872
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
____sys_sendmsg+0x5be/0x970 net/socket.c:2518
___sys_sendmsg+0x2a2/0x360 net/socket.c:2572
__sys_sendmsg net/socket.c:2601 [inline]
__do_sys_sendmsg net/socket.c:2610 [inline]
__se_sys_sendmsg+0x1bb/0x2a0 net/socket.c:2608
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: 0033:0x7f3d7d99ce59
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:00007f3d7e913028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3d7dc15fa0 RCX: 00007f3d7d99ce59
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000013
RBP: 00007f3d7da32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3d7dc16038 R14: 00007f3d7dc15fa0 R15: 00007ffe97bf34f8
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 228da13e907e Linux 6.1.175
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1782f3d2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4dd3c1715f0a309b
dashboard link: https://syzkaller.appspot.com/bug?extid=6c98b89b805fbe7f4ad4
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/894d01ce6736/disk-228da13e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2a4cec18e217/vmlinux-228da13e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/32550387ebe8/bzImage-228da13e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6c98b8...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2652 jiffies s: 62897 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: 19703 Comm: syz.5.4965 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5400 [inline]
RIP: 0010:lock_is_held_type+0xb4/0x190 kernel/locking/lockdep.c:5705
Code: df 49 81 c7 e0 0a 00 00 45 31 e4 49 83 fc 31 73 24 4c 89 ff 4c 89 f6 e8 2a 02 00 00 85 c0 75 2a 49 ff c4 48 63 83 d8 0a 00 00 <49> 83 c7 28 49 39 c4 7c d8 eb 11 48 c7 c7 60 c1 9f 8c 4c 89 e6 e8
RSP: 0018:ffffc900001e0758 EFLAGS: 00000002
RAX: 0000000000000004 RBX: ffff88802b729e00 RCX: 0000000000000000
RDX: ffff88802b729e00 RSI: ffffffff8cb2de60 RDI: ffff88802b72a8e0
RBP: 00000000ffffffff R08: dffffc0000000000 R09: 1ffffffff215fe48
R10: dffffc0000000000 R11: fffffbfff215fe49 R12: 0000000000000001
R13: 0000000000000046 R14: ffffffff8cb2de60 R15: ffff88802b72a8e0
FS: 00007f3d7e9136c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb214017dac CR3: 00000000827fc000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
trace_call_bpf+0x19e/0x6b0 kernel/trace/bpf_trace.c:135
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 82 30 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:ffffc900001e0ac0 EFLAGS: 00000206
RAX: 669f99cbb41e3a00 RBX: 1ffff9200003c160 RCX: 669f99cbb41e3a00
RDX: dffffc0000000000 RSI: ffffffff8a8c1aa0 RDI: ffffffff8adf2060
RBP: ffffc900001e0bb0 R08: ffffffff90aff24f R09: 1ffffffff215fe49
R10: dffffc0000000000 R11: fffffbfff215fe4a 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]
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:1751 [inline]
__hrtimer_run_queues+0x54a/0xd50 kernel/time/hrtimer.c:1815
hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1832
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:__rcu_read_unlock+0x65/0xd0 kernel/rcu/tree_plugin.h:433
Code: 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 75 5f 41 83 3e 00 75 20 43 0f b6 04 3c 84 c0 75 3a 8b 03 3d 00 00 00 40 73 0a <5b> 41 5c 41 5d 41 5e 41 5f c3 0f 0b eb f2 e8 58 00 00 00 eb d9 89
RSP: 0018:ffffc900033b6480 EFLAGS: 00000287
RAX: 0000000000000000 RBX: ffff88802b72a23c RCX: 0000000000080000
RDX: ffffc90013644000 RSI: 00000000000209bd RDI: ffff88802b729e00
RBP: 0000000000000000 R08: dffffc0000000000 R09: 1ffffffff215fe48
R10: dffffc0000000000 R11: fffffbfff215fe49 R12: 1ffff110056e5447
R13: dffffc0000000000 R14: ffff88802b72a240 R15: dffffc0000000000
rcu_read_unlock include/linux/rcupdate.h:823 [inline]
is_bpf_text_address+0x27a/0x2a0 kernel/bpf/core.c:737
kernel_text_address+0x9c/0xd0 kernel/extable.c:125
__kernel_text_address+0x9/0x30 kernel/extable.c:79
unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slab_common.c:936 [inline]
__kmalloc_node_track_caller+0xae/0x230 mm/slab_common.c:956
kmalloc_reserve net/core/skbuff.c:446 [inline]
pskb_expand_head+0x1a6/0x12a0 net/core/skbuff.c:1849
netlink_trim+0x180/0x220 net/netlink/af_netlink.c:1299
netlink_broadcast+0x75/0x10d0 net/netlink/af_netlink.c:1500
nlmsg_multicast include/net/netlink.h:1078 [inline]
nlmsg_notify+0xe7/0x1a0 net/netlink/af_netlink.c:2554
__dev_notify_flags+0xef/0x310 net/core/dev.c:8711
dev_change_flags+0xe4/0x1a0 net/core/dev.c:8753
do_setlink+0xba1/0x3e60 net/core/rtnetlink.c:2837
rtnl_setlink+0x37e/0x510 net/core/rtnetlink.c:3128
rtnetlink_rcv_msg+0x87c/0xfc0 net/core/rtnetlink.c:6158
netlink_rcv_skb+0x1fb/0x450 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+0x8ad/0xbd0 net/netlink/af_netlink.c:1872
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
____sys_sendmsg+0x5be/0x970 net/socket.c:2518
___sys_sendmsg+0x2a2/0x360 net/socket.c:2572
__sys_sendmsg net/socket.c:2601 [inline]
__do_sys_sendmsg net/socket.c:2610 [inline]
__se_sys_sendmsg+0x1bb/0x2a0 net/socket.c:2608
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: 0033:0x7f3d7d99ce59
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:00007f3d7e913028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3d7dc15fa0 RCX: 00007f3d7d99ce59
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000013
RBP: 00007f3d7da32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3d7dc16038 R14: 00007f3d7dc15fa0 R15: 00007ffe97bf34f8
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
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