syzbot


INFO: rcu detected stall in netdev_run_todo

Status: upstream: reported on 2025/11/04 06:17
Reported-by: syzbot+ad0b9c68c6a903e9bd3c@syzkaller.appspotmail.com
First crash: 86d, last: 86d
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in netdev_run_todo kernel 1 1 2789d 2789d 0/29 closed as invalid on 2018/07/20 11:18
linux-5.15 INFO: rcu detected stall in netdev_run_todo 1 1 93d 93d 0/3 upstream: reported on 2025/10/29 01:55

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2631 jiffies s: 47813 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: 13214 Comm: syz.2.3027 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:check_region_inline mm/kasan/generic.c:169 [inline]
RIP: 0010:kasan_check_range+0xb/0x290 mm/kasan/generic.c:189
Code: 31 c0 c3 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 00 00 cc cc 00 00 cc cc 00 00 cc cc b0 01 48 85 f6 0f 84 a4 01 00 00 <41> 57 41 56 53 49 89 f8 49 01 f0 0f 82 57 02 00 00 49 89 f8 49 c1
RSP: 0018:ffffc900000078f8 EFLAGS: 00000002
RAX: 1ffff110171c6801 RBX: ffff8880b8e340b8 RCX: ffffffff818d1677
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8880b8e340b8
RBP: ffffc900000079b0 R08: dffffc0000000000 R09: fffffbfff1c3ed56
R10: fffffbfff1c3ed56 R11: 1ffffffff1c3ed55 R12: 1ffff92000000f20
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f91bfd0d6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f91bfcecd58 CR3: 000000002fa46000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00002000000000c0
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 instrument_atomic_write include/linux/instrumented.h:87 [inline]
 llist_del_all include/linux/llist.h:239 [inline]
 irq_work_run_list kernel/irq_work.c:240 [inline]
 irq_work_run+0x117/0x2e0 kernel/irq_work.c:251
 __sysvec_irq_work+0xba/0x350 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: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 ed 90 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:ffffc90000007aa0 EFLAGS: 00000206
RAX: 414c8c4f57cc2800 RBX: 1ffff92000000f5c RCX: 414c8c4f57cc2800
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: ffffffff8adef760
RBP: ffffc90000007b90 R08: dffffc0000000000 R09: fffffbfff215c455
R10: fffffbfff215c455 R11: 1ffffffff215c454 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+0x554/0xd60 kernel/time/hrtimer.c:1811
 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828
 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:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc9000358f080 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 414c8c4f57cc2800
RDX: 0000000000000000 RSI: ffffffff8a8c1700 RDI: ffffffff8adef760
RBP: ffffc9000358f198 R08: dffffc0000000000 R09: fffffbfff215c455
R10: fffffbfff215c455 R11: 1ffffffff215c454 R12: 0000000000000000
R13: 1ffff920006b1e1c R14: 0000000000000246 R15: dffffc0000000000
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
 __mutex_unlock_slowpath+0x36a/0x6a0 kernel/locking/mutex.c:932
 __rtnl_unlock+0x64/0xe0 net/core/rtnetlink.c:133
 netdev_run_todo+0x2b7/0xd80 net/core/dev.c:10481
 rtnl_unlock net/core/rtnetlink.c:147 [inline]
 rtnetlink_rcv_msg+0xa23/0xed0 net/core/rtnetlink.c:6151
 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: 0033:0x7f91bed8f6c9
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:00007f91bfd0d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f91befe5fa0 RCX: 00007f91bed8f6c9
RDX: 0000000000040000 RSI: 0000200000000600 RDI: 0000000000000007
RBP: 00007f91bee11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f91befe6038 R14: 00007f91befe5fa0 R15: 00007fff5bfa95a8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/04 06:17 linux-6.1.y f6e38ae624cf 686bf657 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in netdev_run_todo
* Struck through repros no longer work on HEAD.