[v6.6] INFO: rcu detected stall in rtnl_newlink
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syzbot
Jun 20, 2025, 6:45:30 AM6/20/25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1355030c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=574b5c9e549e529fe81a
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=163c5370580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+574b5c...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (2 GPs behind) idle=d69c/1/0x4000000000000000 softirq=12592/12593 fqs=1
rcu: (detected by 1, t=10503 jiffies, g=10653, q=336 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5892 Comm: syz-executor Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x0/0x16
Code: 56 57 41 50 41 51 41 52 41 53 e8 5b 08 00 00 41 5b 41 5a 41 59 41 58 5f 5e 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 52 b8 01 00 00 00 31 d2 f0 0f b0 17 3c 01 75 02 5a c3
RSP: 0018:ffffc90000007c20 EFLAGS: 00000082
RAX: 1ffffffff1973958 RBX: ffff88802de312e8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88802de312e8
RBP: 1ffff11005bc625e R08: ffff88802de312eb R09: 1ffff11005bc625d
R10: dffffc0000000000 R11: ffffed1005bc625e R12: dffffc0000000000
R13: 1ffff11005bc625f R14: ffff88802de312f8 R15: ffff88802de312f0
FS: 000055557d2af500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000300 CR3: 00000000626ad000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:591 [inline]
queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline]
do_raw_spin_unlock+0x121/0x230 kernel/locking/spinlock_debug.c:141
__raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_unlock+0x1e/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
advance_sched+0x9a0/0xc80 net/sched/sch_taprio.c:992
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:console_flush_all+0x889/0xd00 arch/x86/include/asm/irqflags.h:-1
Code: ed 01 00 00 e8 18 38 1b 00 4d 85 ff 48 8b 5c 24 38 75 07 e8 09 38 1b 00 eb 06 e8 02 38 1b 00 fb 49 bf 00 00 00 00 00 fc ff df <48> 8b 44 24 50 42 0f b6 04 38 84 c0 0f 85 2f 02 00 00 80 3b 01 0f
RSP: 0018:ffffc900033667c0 EFLAGS: 00000293
RAX: ffffffff816a5dce RBX: ffffc9000336695f RCX: ffff88802c20bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003366930 R08: ffffffff90d85527 R09: 1ffffffff21b0aa4
R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: ffffffff8d4b68e0
R13: 1ffffffff1979228 R14: ffffffff8d4b6938 R15: dffffc0000000000
console_unlock+0xae/0x340 kernel/printk/printk.c:3069
vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
_printk+0xd0/0x110 kernel/printk/printk.c:2366
batadv_check_known_mac_addr+0x29b/0x3e0 net/batman-adv/hard-interface.c:526
batadv_hard_if_event+0x3a3/0x15b0 net/batman-adv/hard-interface.c:998
notifier_call_chain+0x197/0x390 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
call_netdevice_notifiers net/core/dev.c:2078 [inline]
dev_set_mac_address+0x377/0x4b0 net/core/dev.c:8936
dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8950
do_setlink+0x871/0x3fb0 net/core/rtnetlink.c:2860
__rtnl_newlink net/core/rtnetlink.c:3703 [inline]
rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750
rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2537
netlink_unicast_kernel net/netlink/af_netlink.c:1323 [inline]
netlink_unicast+0x750/0x8c0 net/netlink/af_netlink.c:1349
netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x46a/0x620 net/socket.c:2201
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0xf0 net/socket.c:2209
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0bf3b907bc
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007ffcc8fe7cc0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0bf48e4620 RCX: 00007f0bf3b907bc
RDX: 000000000000002c RSI: 00007f0bf48e4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffcc8fe7d14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f0bf48e4670 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 10497 jiffies! g10653 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27464 pid:17 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14e2/0x4580 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 142 Comm: kworker/u4:5 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xddf/0x1130 kernel/smp.c:855
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 1a e7 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 55 e3 0a 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 39 e3
RSP: 0018:ffffc90002e47780 EFLAGS: 00000293
RAX: ffffffff817ab297 RBX: 1ffff110171c87d9 RCX: ffff88801abf8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002e47900 R08: ffffffff90d85527 R09: 1ffffffff21b0aa4
R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: ffff8880b8e43ec8
R13: dffffc0000000000 R14: ffff8880b8f3d588 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c090326640 CR3: 000000000cb30000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:2222 [inline]
text_poke_bp_batch+0x318/0x930 arch/x86/kernel/alternative.c:2432
text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
static_key_enable+0x1a/0x20 kernel/jump_label.c:220
toggle_allocation_gate+0xaa/0x250 mm/kfence/core.c:831
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
watchdog: BUG: soft lockup - CPU#1 stuck for 246s! [kworker/u4:5:142]
Modules linked in:
irq event stamp: 977310
hardirqs last enabled at (977309): [<ffffffff8a80144a>] asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
hardirqs last disabled at (977310): [<ffffffff8a662e8e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1088
softirqs last enabled at (977306): [<ffffffff81518d67>] __do_softirq kernel/softirq.c:612 [inline]
softirqs last enabled at (977306): [<ffffffff81518d67>] invoke_softirq kernel/softirq.c:452 [inline]
softirqs last enabled at (977306): [<ffffffff81518d67>] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
softirqs last disabled at (977287): [<ffffffff81518d67>] __do_softirq kernel/softirq.c:612 [inline]
softirqs last disabled at (977287): [<ffffffff81518d67>] invoke_softirq kernel/softirq.c:452 [inline]
softirqs last disabled at (977287): [<ffffffff81518d67>] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
CPU: 1 PID: 142 Comm: kworker/u4:5 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xddf/0x1130 kernel/smp.c:855
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 1a e7 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 55 e3 0a 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 39 e3
RSP: 0018:ffffc90002e47780 EFLAGS: 00000293
RAX: ffffffff817ab297 RBX: 1ffff110171c87d9 RCX: ffff88801abf8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002e47900 R08: ffffffff90d85527 R09: 1ffffffff21b0aa4
R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: ffff8880b8e43ec8
R13: dffffc0000000000 R14: ffff8880b8f3d588 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c090326640 CR3: 000000000cb30000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:2222 [inline]
text_poke_bp_batch+0x318/0x930 arch/x86/kernel/alternative.c:2432
text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
static_key_enable+0x1a/0x20 kernel/jump_label.c:220
toggle_allocation_gate+0xaa/0x250 mm/kfence/core.c:831
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5892 Comm: syz-executor Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212
Code: 00 0f 0b 0f 1f 80 00 00 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 8c 17 c4 0c 48 89 de 5b e9 83 d6 57 00 cc cc cc <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0d 20 24 7e 7e 65 8b 15 21 24 7e
RSP: 0018:ffffc90000007c68 EFLAGS: 00000046
RAX: ffff88802f6f9110 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000001cb0e3946b
RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f7c R12: ffff88802f6f9110
R13: ffff88802de31000 R14: 0000001cb0e3946b R15: ffff88802f6f9940
FS: 000055557d2af500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000300 CR3: 00000000626ad000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
should_restart_cycle net/sched/sch_taprio.c:880 [inline]
advance_sched+0x3c0/0xc80 net/sched/sch_taprio.c:959
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:console_flush_all+0x889/0xd00 arch/x86/include/asm/irqflags.h:-1
Code: ed 01 00 00 e8 18 38 1b 00 4d 85 ff 48 8b 5c 24 38 75 07 e8 09 38 1b 00 eb 06 e8 02 38 1b 00 fb 49 bf 00 00 00 00 00 fc ff df <48> 8b 44 24 50 42 0f b6 04 38 84 c0 0f 85 2f 02 00 00 80 3b 01 0f
RSP: 0018:ffffc900033667c0 EFLAGS: 00000293
RAX: ffffffff816a5dce RBX: ffffc9000336695f RCX: ffff88802c20bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003366930 R08: ffffffff90d85527 R09: 1ffffffff21b0aa4
R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: ffffffff8d4b68e0
R13: 1ffffffff1979228 R14: ffffffff8d4b6938 R15: dffffc0000000000
console_unlock+0xae/0x340 kernel/printk/printk.c:3069
vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
_printk+0xd0/0x110 kernel/printk/printk.c:2366
batadv_check_known_mac_addr+0x29b/0x3e0 net/batman-adv/hard-interface.c:526
batadv_hard_if_event+0x3a3/0x15b0 net/batman-adv/hard-interface.c:998
notifier_call_chain+0x197/0x390 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
call_netdevice_notifiers net/core/dev.c:2078 [inline]
dev_set_mac_address+0x377/0x4b0 net/core/dev.c:8936
dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8950
do_setlink+0x871/0x3fb0 net/core/rtnetlink.c:2860
__rtnl_newlink net/core/rtnetlink.c:3703 [inline]
rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750
rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2537
netlink_unicast_kernel net/netlink/af_netlink.c:1323 [inline]
netlink_unicast+0x750/0x8c0 net/netlink/af_netlink.c:1349
netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x46a/0x620 net/socket.c:2201
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0xf0 net/socket.c:2209
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0bf3b907bc
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007ffcc8fe7cc0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0bf48e4620 RCX: 00007f0bf3b907bc
RDX: 000000000000002c RSI: 00007f0bf48e4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffcc8fe7d14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f0bf48e4670 R15: 0000000000000000
</TASK>
---
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syzbot found the following issue on:
HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1355030c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427
dashboard link: https://syzkaller.appspot.com/bug?extid=574b5c9e549e529fe81a
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=163c5370580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a3bf0d8e22b2/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d1d442f782d0/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8378f4b7e1b/bzImage-6282921b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+574b5c...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (2 GPs behind) idle=d69c/1/0x4000000000000000 softirq=12592/12593 fqs=1
rcu: (detected by 1, t=10503 jiffies, g=10653, q=336 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5892 Comm: syz-executor Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x0/0x16
Code: 56 57 41 50 41 51 41 52 41 53 e8 5b 08 00 00 41 5b 41 5a 41 59 41 58 5f 5e 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 52 b8 01 00 00 00 31 d2 f0 0f b0 17 3c 01 75 02 5a c3
RSP: 0018:ffffc90000007c20 EFLAGS: 00000082
RAX: 1ffffffff1973958 RBX: ffff88802de312e8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88802de312e8
RBP: 1ffff11005bc625e R08: ffff88802de312eb R09: 1ffff11005bc625d
R10: dffffc0000000000 R11: ffffed1005bc625e R12: dffffc0000000000
R13: 1ffff11005bc625f R14: ffff88802de312f8 R15: ffff88802de312f0
FS: 000055557d2af500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000300 CR3: 00000000626ad000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:591 [inline]
queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline]
do_raw_spin_unlock+0x121/0x230 kernel/locking/spinlock_debug.c:141
__raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_unlock+0x1e/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
advance_sched+0x9a0/0xc80 net/sched/sch_taprio.c:992
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:console_flush_all+0x889/0xd00 arch/x86/include/asm/irqflags.h:-1
Code: ed 01 00 00 e8 18 38 1b 00 4d 85 ff 48 8b 5c 24 38 75 07 e8 09 38 1b 00 eb 06 e8 02 38 1b 00 fb 49 bf 00 00 00 00 00 fc ff df <48> 8b 44 24 50 42 0f b6 04 38 84 c0 0f 85 2f 02 00 00 80 3b 01 0f
RSP: 0018:ffffc900033667c0 EFLAGS: 00000293
RAX: ffffffff816a5dce RBX: ffffc9000336695f RCX: ffff88802c20bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003366930 R08: ffffffff90d85527 R09: 1ffffffff21b0aa4
R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: ffffffff8d4b68e0
R13: 1ffffffff1979228 R14: ffffffff8d4b6938 R15: dffffc0000000000
console_unlock+0xae/0x340 kernel/printk/printk.c:3069
vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
_printk+0xd0/0x110 kernel/printk/printk.c:2366
batadv_check_known_mac_addr+0x29b/0x3e0 net/batman-adv/hard-interface.c:526
batadv_hard_if_event+0x3a3/0x15b0 net/batman-adv/hard-interface.c:998
notifier_call_chain+0x197/0x390 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
call_netdevice_notifiers net/core/dev.c:2078 [inline]
dev_set_mac_address+0x377/0x4b0 net/core/dev.c:8936
dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8950
do_setlink+0x871/0x3fb0 net/core/rtnetlink.c:2860
__rtnl_newlink net/core/rtnetlink.c:3703 [inline]
rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750
rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2537
netlink_unicast_kernel net/netlink/af_netlink.c:1323 [inline]
netlink_unicast+0x750/0x8c0 net/netlink/af_netlink.c:1349
netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x46a/0x620 net/socket.c:2201
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0xf0 net/socket.c:2209
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0bf3b907bc
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007ffcc8fe7cc0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0bf48e4620 RCX: 00007f0bf3b907bc
RDX: 000000000000002c RSI: 00007f0bf48e4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffcc8fe7d14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f0bf48e4670 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 10497 jiffies! g10653 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27464 pid:17 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x14e2/0x4580 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 142 Comm: kworker/u4:5 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xddf/0x1130 kernel/smp.c:855
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 1a e7 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 55 e3 0a 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 39 e3
RSP: 0018:ffffc90002e47780 EFLAGS: 00000293
RAX: ffffffff817ab297 RBX: 1ffff110171c87d9 RCX: ffff88801abf8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002e47900 R08: ffffffff90d85527 R09: 1ffffffff21b0aa4
R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: ffff8880b8e43ec8
R13: dffffc0000000000 R14: ffff8880b8f3d588 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c090326640 CR3: 000000000cb30000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:2222 [inline]
text_poke_bp_batch+0x318/0x930 arch/x86/kernel/alternative.c:2432
text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
static_key_enable+0x1a/0x20 kernel/jump_label.c:220
toggle_allocation_gate+0xaa/0x250 mm/kfence/core.c:831
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
watchdog: BUG: soft lockup - CPU#1 stuck for 246s! [kworker/u4:5:142]
Modules linked in:
irq event stamp: 977310
hardirqs last enabled at (977309): [<ffffffff8a80144a>] asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
hardirqs last disabled at (977310): [<ffffffff8a662e8e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1088
softirqs last enabled at (977306): [<ffffffff81518d67>] __do_softirq kernel/softirq.c:612 [inline]
softirqs last enabled at (977306): [<ffffffff81518d67>] invoke_softirq kernel/softirq.c:452 [inline]
softirqs last enabled at (977306): [<ffffffff81518d67>] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
softirqs last disabled at (977287): [<ffffffff81518d67>] __do_softirq kernel/softirq.c:612 [inline]
softirqs last disabled at (977287): [<ffffffff81518d67>] invoke_softirq kernel/softirq.c:452 [inline]
softirqs last disabled at (977287): [<ffffffff81518d67>] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
CPU: 1 PID: 142 Comm: kworker/u4:5 Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xddf/0x1130 kernel/smp.c:855
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 1a e7 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 55 e3 0a 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 39 e3
RSP: 0018:ffffc90002e47780 EFLAGS: 00000293
RAX: ffffffff817ab297 RBX: 1ffff110171c87d9 RCX: ffff88801abf8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002e47900 R08: ffffffff90d85527 R09: 1ffffffff21b0aa4
R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: ffff8880b8e43ec8
R13: dffffc0000000000 R14: ffff8880b8f3d588 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c090326640 CR3: 000000000cb30000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:2222 [inline]
text_poke_bp_batch+0x318/0x930 arch/x86/kernel/alternative.c:2432
text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
static_key_enable+0x1a/0x20 kernel/jump_label.c:220
toggle_allocation_gate+0xaa/0x250 mm/kfence/core.c:831
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5892 Comm: syz-executor Not tainted 6.6.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212
Code: 00 0f 0b 0f 1f 80 00 00 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 8c 17 c4 0c 48 89 de 5b e9 83 d6 57 00 cc cc cc <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0d 20 24 7e 7e 65 8b 15 21 24 7e
RSP: 0018:ffffc90000007c68 EFLAGS: 00000046
RAX: ffff88802f6f9110 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000001cb0e3946b
RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f7c R12: ffff88802f6f9110
R13: ffff88802de31000 R14: 0000001cb0e3946b R15: ffff88802f6f9940
FS: 000055557d2af500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000300 CR3: 00000000626ad000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
should_restart_cycle net/sched/sch_taprio.c:880 [inline]
advance_sched+0x3c0/0xc80 net/sched/sch_taprio.c:959
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:console_flush_all+0x889/0xd00 arch/x86/include/asm/irqflags.h:-1
Code: ed 01 00 00 e8 18 38 1b 00 4d 85 ff 48 8b 5c 24 38 75 07 e8 09 38 1b 00 eb 06 e8 02 38 1b 00 fb 49 bf 00 00 00 00 00 fc ff df <48> 8b 44 24 50 42 0f b6 04 38 84 c0 0f 85 2f 02 00 00 80 3b 01 0f
RSP: 0018:ffffc900033667c0 EFLAGS: 00000293
RAX: ffffffff816a5dce RBX: ffffc9000336695f RCX: ffff88802c20bc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003366930 R08: ffffffff90d85527 R09: 1ffffffff21b0aa4
R10: dffffc0000000000 R11: fffffbfff21b0aa5 R12: ffffffff8d4b68e0
R13: 1ffffffff1979228 R14: ffffffff8d4b6938 R15: dffffc0000000000
console_unlock+0xae/0x340 kernel/printk/printk.c:3069
vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
_printk+0xd0/0x110 kernel/printk/printk.c:2366
batadv_check_known_mac_addr+0x29b/0x3e0 net/batman-adv/hard-interface.c:526
batadv_hard_if_event+0x3a3/0x15b0 net/batman-adv/hard-interface.c:998
notifier_call_chain+0x197/0x390 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2064 [inline]
call_netdevice_notifiers net/core/dev.c:2078 [inline]
dev_set_mac_address+0x377/0x4b0 net/core/dev.c:8936
dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8950
do_setlink+0x871/0x3fb0 net/core/rtnetlink.c:2860
__rtnl_newlink net/core/rtnetlink.c:3703 [inline]
rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750
rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2537
netlink_unicast_kernel net/netlink/af_netlink.c:1323 [inline]
netlink_unicast+0x750/0x8c0 net/netlink/af_netlink.c:1349
netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x46a/0x620 net/socket.c:2201
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0xf0 net/socket.c:2209
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0bf3b907bc
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007ffcc8fe7cc0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0bf48e4620 RCX: 00007f0bf3b907bc
RDX: 000000000000002c RSI: 00007f0bf48e4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffcc8fe7d14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f0bf48e4670 R15: 0000000000000000
</TASK>
---
This report is generated by a bot. It may contain errors.
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syzbot
Jun 21, 2026, 1:02:30 AM (5 days ago) Jun 21
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: d1cfde2d5d15 Linux 6.6.143
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1631e8ea580000
kernel config: https://syzkaller.appspot.com/x/.config?x=441765643cbfb8d
dashboard link: https://syzkaller.appspot.com/bug?extid=574b5c9e549e529fe81a
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13dc501c580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14daa01c580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4e37bcd98892/disk-d1cfde2d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/64b2ed856057/vmlinux-d1cfde2d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0a6949479d66/bzImage-d1cfde2d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+574b5c...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5910/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=11117, q=560 ncpus=2)
task:syz-executor state:R running task stack:22280 pid:5910 ppid:5905 flags:0x00004002
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:preempt_schedule+0x92/0xd0 kernel/sched/core.c:6892
Code: 48 b8 04 00 00 00 00 fc ff df c6 04 03 00 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 c6 04 03 f8 75 29 <48> c7 04 24 0e 36 e0 45 4a c7 04 33 00 00 00 00 65 48 8b 04 25 28
RSP: 0018:ffffc900032e6960 EFLAGS: 00000246
RAX: 1ffff11004953b40 RBX: 1ffff9200065cd2c RCX: 96572b2a9bc3aa00
RDX: dffffc0000000000 RSI: ffffffff8acacb60 RDI: ffff888024a9eff8
RBP: ffffc900032e69d8 R08: ffffffff911bc5c7 R09: 1ffffffff22378b8
R10: dffffc0000000000 R11: fffffbfff22378b9 R12: dffffc0000000000
R13: 1ffff9200065cd4c R14: dffffc0000000000 R15: 000000000000005d
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
vprintk_emit+0x587/0x610 kernel/printk/printk.c:2342
_printk+0xde/0x130 kernel/printk/printk.c:2366
batadv_check_known_mac_addr+0x29a/0x3e0 net/batman-adv/hard-interface.c:526
batadv_hard_if_event+0x3a2/0x1570 net/batman-adv/hard-interface.c:998
notifier_call_chain+0x18f/0x380 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2077 [inline]
call_netdevice_notifiers net/core/dev.c:2091 [inline]
dev_set_mac_address+0x38e/0x4d0 net/core/dev.c:8986
dev_set_mac_address_user+0x31/0x50 net/core/dev.c:9000
do_setlink+0x78f/0x3f40 net/core/rtnetlink.c:2864
__rtnl_newlink net/core/rtnetlink.c:3707 [inline]
rtnl_newlink+0x1848/0x2170 net/core/rtnetlink.c:3754
rtnetlink_rcv_msg+0x843/0xf90 net/core/rtnetlink.c:6476
netlink_rcv_skb+0x235/0x4c0 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd26ff5d68e
RSP: 002b:00007ffc405abb98 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555562d90500 RCX: 00007fd26ff5d68e
RDX: 000000000000002c RSI: 00007fd270d44670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffc405abc14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fd270d44670 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 10560 jiffies! g11117 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__timer_delete_sync+0x275/0x2e0 kernel/time/timer.c:1582
Code: 00 00 fc ff df 49 c7 44 05 00 00 00 00 00 41 c7 44 05 08 00 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 80 00 00 00 75 1b <44> 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 84 8f 10
RSP: 0018:ffffc90000167aa0 EFLAGS: 00000246
RAX: f8f38a1d3f93a500 RBX: ffffc90000167ba0 RCX: ffff88801b648000
R10: dffffc0000000000 R11: fffffbfff1d15cbe R12: ffffffff8176544e
R13: 1ffff9200002cf58 R14: 0000000000000000 R15: 0000000000000000
timer_delete_sync kernel/time/timer.c:1629 [inline]
del_timer_sync include/linux/timer.h:200 [inline]
schedule_timeout+0x192/0x2d0 kernel/time/timer.c:2169
rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_acquire+0xe4a/0x7d80 kernel/locking/lockdep.c:5120
Code: 00 00 84 c9 0f 84 60 0a 00 00 48 89 d8 48 c1 e8 03 42 80 3c 00 00 74 12 48 89 df e8 10 44 77 00 49 b8 00 00 00 00 00 fc ff df <4c> 89 3b 48 8b 44 24 78 42 0f b6 04 00 84 c0 0f 85 a5 0d 00 00 48
RSP: 0018:ffffc900043174c0 EFLAGS: 00000046
RAX: 1ffff11005a92161 RBX: ffff88802d490b08 RCX: ffffffff816815a2
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911bc510
RBP: ffffc90004317708 R08: dffffc0000000000 R09: 1ffffffff22378a2
R10: dffffc0000000000 R11: fffffbfff22378a3 R12: 0000000000040000
R13: ffff88802d490000 R14: ffff88802d490ad0 R15: 21172683b190bb39
FS: 00007ff11530f6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
Call Trace:
<TASK>
lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
do_write_seqcount_begin_nested include/linux/seqlock.h:515 [inline]
do_write_seqcount_begin include/linux/seqlock.h:541 [inline]
psi_write_begin kernel/sched/psi.c:179 [inline]
psi_account_irqtime+0x236/0x810 kernel/sched/psi.c:1034
__schedule+0x8c8/0x4660 kernel/sched/core.c:6694
schedule+0xbd/0x170 kernel/sched/core.c:6774
futex_wait_queue+0x138/0x1b0 kernel/futex/waitwake.c:355
futex_wait+0x1e9/0x5c0 kernel/futex/waitwake.c:656
do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134
__do_sys_futex kernel/futex/syscalls.c:211 [inline]
__se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff11439ce59
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:00007ff11530f0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007ff114615fa8 RCX: 00007ff11439ce59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff114615fa8
RBP: 00007ff114615fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff114616038 R14: 00007ffcc7ec0b90 R15: 00007ffcc7ec0c78
</TASK>
sched: RT throttling activated
---
HEAD commit: d1cfde2d5d15 Linux 6.6.143
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1631e8ea580000
kernel config: https://syzkaller.appspot.com/x/.config?x=441765643cbfb8d
dashboard link: https://syzkaller.appspot.com/bug?extid=574b5c9e549e529fe81a
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13dc501c580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14daa01c580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4e37bcd98892/disk-d1cfde2d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/64b2ed856057/vmlinux-d1cfde2d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0a6949479d66/bzImage-d1cfde2d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+574b5c...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: (detected by 1, t=10503 jiffies, g=11117, q=560 ncpus=2)
task:syz-executor state:R running task stack:22280 pid:5910 ppid:5905 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6700
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:preempt_schedule+0x92/0xd0 kernel/sched/core.c:6892
Code: 48 b8 04 00 00 00 00 fc ff df c6 04 03 00 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 c6 04 03 f8 75 29 <48> c7 04 24 0e 36 e0 45 4a c7 04 33 00 00 00 00 65 48 8b 04 25 28
RSP: 0018:ffffc900032e6960 EFLAGS: 00000246
RAX: 1ffff11004953b40 RBX: 1ffff9200065cd2c RCX: 96572b2a9bc3aa00
RDX: dffffc0000000000 RSI: ffffffff8acacb60 RDI: ffff888024a9eff8
RBP: ffffc900032e69d8 R08: ffffffff911bc5c7 R09: 1ffffffff22378b8
R10: dffffc0000000000 R11: fffffbfff22378b9 R12: dffffc0000000000
R13: 1ffff9200065cd4c R14: dffffc0000000000 R15: 000000000000005d
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
vprintk_emit+0x587/0x610 kernel/printk/printk.c:2342
_printk+0xde/0x130 kernel/printk/printk.c:2366
batadv_check_known_mac_addr+0x29a/0x3e0 net/batman-adv/hard-interface.c:526
batadv_hard_if_event+0x3a2/0x1570 net/batman-adv/hard-interface.c:998
notifier_call_chain+0x18f/0x380 kernel/notifier.c:93
call_netdevice_notifiers_extack net/core/dev.c:2077 [inline]
call_netdevice_notifiers net/core/dev.c:2091 [inline]
dev_set_mac_address+0x38e/0x4d0 net/core/dev.c:8986
dev_set_mac_address_user+0x31/0x50 net/core/dev.c:9000
do_setlink+0x78f/0x3f40 net/core/rtnetlink.c:2864
__rtnl_newlink net/core/rtnetlink.c:3707 [inline]
rtnl_newlink+0x1848/0x2170 net/core/rtnetlink.c:3754
rtnetlink_rcv_msg+0x843/0xf90 net/core/rtnetlink.c:6476
netlink_rcv_skb+0x235/0x4c0 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x4a9/0x6b0 net/socket.c:2201
__sock_sendmsg net/socket.c:745 [inline]
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0xf0 net/socket.c:2209
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0xf0 net/socket.c:2209
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd26ff5d68e
RSP: 002b:00007ffc405abb98 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555562d90500 RCX: 00007fd26ff5d68e
RDX: 000000000000002c RSI: 00007fd270d44670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffc405abc14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fd270d44670 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 10560 jiffies! g11117 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:26856 pid:17 ppid:2 flags:0x00004000
rcu: RCU grace-period kthread stack dump:
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6700
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__timer_delete_sync+0x275/0x2e0 kernel/time/timer.c:1582
Code: 00 00 fc ff df 49 c7 44 05 00 00 00 00 00 41 c7 44 05 08 00 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 80 00 00 00 75 1b <44> 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 84 8f 10
RSP: 0018:ffffc90000167aa0 EFLAGS: 00000246
RAX: f8f38a1d3f93a500 RBX: ffffc90000167ba0 RCX: ffff88801b648000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000167b70 R08: ffffffff8e8ae5ef R09: 1ffffffff1d15cbd
R10: dffffc0000000000 R11: fffffbfff1d15cbe R12: ffffffff8176544e
R13: 1ffff9200002cf58 R14: 0000000000000000 R15: 0000000000000000
timer_delete_sync kernel/time/timer.c:1629 [inline]
del_timer_sync include/linux/timer.h:200 [inline]
schedule_timeout+0x192/0x2d0 kernel/time/timer.c:2169
rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6188 Comm: syz.2.19 Not tainted syzkaller #0
NMI backtrace for cpu 0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_acquire+0xe4a/0x7d80 kernel/locking/lockdep.c:5120
Code: 00 00 84 c9 0f 84 60 0a 00 00 48 89 d8 48 c1 e8 03 42 80 3c 00 00 74 12 48 89 df e8 10 44 77 00 49 b8 00 00 00 00 00 fc ff df <4c> 89 3b 48 8b 44 24 78 42 0f b6 04 00 84 c0 0f 85 a5 0d 00 00 48
RSP: 0018:ffffc900043174c0 EFLAGS: 00000046
RAX: 1ffff11005a92161 RBX: ffff88802d490b08 RCX: ffffffff816815a2
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911bc510
RBP: ffffc90004317708 R08: dffffc0000000000 R09: 1ffffffff22378a2
R10: dffffc0000000000 R11: fffffbfff22378a3 R12: 0000000000040000
R13: ffff88802d490000 R14: ffff88802d490ad0 R15: 21172683b190bb39
FS: 00007ff11530f6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000060c70000 CR4: 00000000003506f0
Call Trace:
<TASK>
lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
do_write_seqcount_begin_nested include/linux/seqlock.h:515 [inline]
do_write_seqcount_begin include/linux/seqlock.h:541 [inline]
psi_write_begin kernel/sched/psi.c:179 [inline]
psi_account_irqtime+0x236/0x810 kernel/sched/psi.c:1034
__schedule+0x8c8/0x4660 kernel/sched/core.c:6694
schedule+0xbd/0x170 kernel/sched/core.c:6774
futex_wait_queue+0x138/0x1b0 kernel/futex/waitwake.c:355
futex_wait+0x1e9/0x5c0 kernel/futex/waitwake.c:656
do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134
__do_sys_futex kernel/futex/syscalls.c:211 [inline]
__se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff11439ce59
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:00007ff11530f0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007ff114615fa8 RCX: 00007ff11439ce59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff114615fa8
RBP: 00007ff114615fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff114616038 R14: 00007ffcc7ec0b90 R15: 00007ffcc7ec0c78
</TASK>
sched: RT throttling activated
---
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