Hello,
syzbot found the following issue on:
HEAD commit: 3b9f64db0496 Linux 6.6.138
git tree: linux-6.6.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=122ba3ce580000
kernel config:
https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link:
https://syzkaller.appspot.com/bug?extid=2c434dba510c815fb3ae
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/191b79864499/disk-3b9f64db.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/7190b56a582e/vmlinux-3b9f64db.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/afa2fbf1faa4/bzImage-3b9f64db.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+2c434d...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-....: (10459 ticks this GP) idle=f1dc/1/0x4000000000000000 softirq=11216/11216 fqs=711
rcu: hardirqs softirqs csw/system
rcu: number: 1400025 0 0
rcu: cputime: 13536 34543 41 ==> 48090(ms)
rcu: (t=10501 jiffies g=8929 q=1504 ncpus=2)
CPU: 0 PID: 5987 Comm: syz.1.36 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x96/0x120 kernel/kcov.c:350
Code: 41 54 53 48 8b 54 24 20 65 4c 8b 05 84 8e 7c 7e 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d 72 8e 7c 7e <41> 81 e3 00 01 ff 00 74 13 41 81 fb 00 01 00 00 75 d9 41 83 b8 1c
RSP: 0018:ffffc90000005f70 EFLAGS: 00000202
RAX: 0000000000000003 RBX: ffffffff8f8aa652 RCX: 0000000000000003
RDX: ffffffff813b4e99 RSI: ffffffff8cfa0860 RDI: 0000000000000001
RBP: ffffc900000060b8 R08: ffff888026e48000 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000305 R12: ffffc90000006068
R13: dffffc0000000000 R14: 0000000000000001 R15: ffffffff8f8aa656
FS: 00007f532affa6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d617ff8 CR3: 000000002f054000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
unwind_next_frame+0x16d9/0x2970 arch/x86/kernel/unwind_orc.c:641
arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767
slab_alloc_node mm/slub.c:3495 [inline]
slab_alloc mm/slub.c:3503 [inline]
__kmem_cache_alloc_lru mm/slub.c:3510 [inline]
kmem_cache_alloc+0x11a/0x2d0 mm/slub.c:3519
skb_clone+0x1eb/0x370 net/core/skbuff.c:1912
dev_queue_xmit_nit+0x24d/0xbb0 net/core/dev.c:2353
xmit_one net/core/dev.c:3640 [inline]
dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3660
sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:3881 [inline]
__dev_queue_xmit+0x165d/0x3660 net/core/dev.c:4416
dev_queue_xmit include/linux/netdevice.h:3113 [inline]
neigh_hh_output include/net/neighbour.h:527 [inline]
neigh_output include/net/neighbour.h:541 [inline]
ip_finish_output2+0xcec/0x11e0 net/ipv4/ip_output.c:235
NF_HOOK_COND include/linux/netfilter.h:293 [inline]
ip_output+0x2a1/0x3b0 net/ipv4/ip_output.c:436
dst_output include/net/dst.h:467 [inline]
ip_local_out net/ipv4/ip_output.c:129 [inline]
__ip_queue_xmit+0x1049/0x1950 net/ipv4/ip_output.c:540
__tcp_transmit_skb+0x1d6b/0x33f0 net/ipv4/tcp_output.c:1425
tcp_validate_incoming+0xf13/0x2250 net/ipv4/tcp_input.c:5901
tcp_rcv_established+0x7de/0x1d20 net/ipv4/tcp_input.c:6166
tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1735
tcp_v4_rcv+0x23bf/0x2af0 net/ipv4/tcp_ipv4.c:2167
ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x2ca/0x510 net/ipv4/ip_input.c:233
NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304
dst_input include/net/dst.h:477 [inline]
ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline]
ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline]
ip_sublist_rcv+0xa4c/0xd70 net/ipv4/ip_input.c:639
ip_list_rcv+0x3f2/0x440 net/ipv4/ip_input.c:674
__netif_receive_skb_list_ptype net/core/dev.c:5689 [inline]
__netif_receive_skb_list_core+0x2da/0x750 net/core/dev.c:5727
__netif_receive_skb_list net/core/dev.c:5789 [inline]
netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5880
gro_normal_list include/net/gro.h:451 [inline]
gro_normal_one include/net/gro.h:464 [inline]
napi_skb_finish net/core/gro.c:575 [inline]
napi_gro_receive+0x565/0xb00 net/core/gro.c:605
receive_buf+0x2203/0x3820 drivers/net/virtio_net.c:1870
virtnet_receive drivers/net/virtio_net.c:2155 [inline]
virtnet_poll+0x5dd/0x1280 drivers/net/virtio_net.c:2229
__napi_poll+0xc0/0x460 net/core/dev.c:6650
napi_poll net/core/dev.c:6717 [inline]
net_rx_action+0x616/0xc40 net/core/dev.c:6853
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 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:finish_task_switch+0x272/0x8f0 kernel/sched/core.c:5255
Code: db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 00 a9 32 09 e8 9b 29 30 00 fb 4c 8b 65 c0 49 8d bc 24 f8 15 00 00 <48> 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 d6 02 00 00 41 80
RSP: 0018:ffffc90005757558 EFLAGS: 00000282
RAX: 444d10be5a967d00 RBX: 0000000000000000 RCX: 444d10be5a967d00
RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: ffff888026e495f8
RBP: ffffc900057575b0 R08: ffffffff911c65ff R09: 1ffffffff2238cbf
R10: dffffc0000000000 R11: fffffbfff2238cc0 R12: ffff888026e48000
R13: dffffc0000000000 R14: ffff88802b74bc00 R15: ffff8880b8e3cac8
context_switch kernel/sched/core.c:5384 [inline]
__schedule+0x155b/0x45a0 kernel/sched/core.c:6700
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:smp_call_function_single+0x483/0x5a0 kernel/smp.c:652
Code: 44 89 e0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 d0 0a 0b 00 0f 0b e9 77 fc ff ff e8 c4 0a 0b 00 0f 0b e9 56 fd ff ff <e8> b8 0a 0b 00 e8 03 86 84 ff eb 90 e8 ac 0a 0b 00 0f 0b e9 14 fd
RSP: 0018:ffffc90005757940 EFLAGS: 00000246
RAX: ffffffff817c16d6 RBX: 0000000000000000 RCX: 0000000000000002
RDX: ffff888026e48000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90005757a30 R08: ffffffff911c65ff R09: 1ffffffff2238cbf
R10: dffffc0000000000 R11: fffffbfff2238cc0 R12: 0000000000000000
R13: dffffc0000000000 R14: 1ffff92000aeaf2c R15: 1ffff92000aeaf2c
task_function_call kernel/events/core.c:120 [inline]
event_function_call+0x359/0x650 kernel/events/core.c:305
_perf_event_period kernel/events/core.c:5906 [inline]
_perf_ioctl kernel/events/core.c:5975 [inline]
perf_ioctl+0x1fdc/0x24a0 kernel/events/core.c:6076
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f532a19ce59
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:00007f532affa028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f532a415fa0 RCX: 00007f532a19ce59
RDX: 0000200000000280 RSI: 0000000040082404 RDI: 0000000000000004
RBP: 00007f532a232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f532a416038 R14: 00007f532a415fa0 R15: 00007fff30a32698
</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