==================================================================
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline]
BUG: KASAN: use-after-free in enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
Write of size 8 at addr ffff8881ddb931c8 by task syz.0.1064/4105
CPU: 0 PID: 4105 Comm: syz.0.1064 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
__dump_stack+0x1e/0x20 lib/dump_stack.c:77
dump_stack+0x15b/0x1b8 lib/dump_stack.c:118
print_address_description+0x8d/0x4c0 mm/kasan/report.c:384
__kasan_report+0xef/0x120 mm/kasan/report.c:516
kasan_report+0x30/0x60 mm/kasan/common.c:653
__asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:137
hlist_add_head include/linux/list.h:814 [inline]
enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541
__internal_add_timer kernel/time/timer.c:554 [inline]
internal_add_timer+0x208/0x3e0 kernel/time/timer.c:604
__mod_timer+0x5ab/0x1150 kernel/time/timer.c:1065
mod_timer+0x1f/0x30 kernel/time/timer.c:1117
can_stat_update+0xbab/0xc40 net/can/proc.c:186
call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448
expire_timers kernel/time/timer.c:1493 [inline]
__run_timers+0x81d/0xb60 kernel/time/timer.c:1817
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
__do_softirq+0x236/0x660 kernel/softirq.c:292
do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1086
do_softirq+0xf9/0x140 kernel/softirq.c:337
__local_bh_enable_ip+0x70/0x80 kernel/softirq.c:189
local_bh_enable+0x1f/0x30 include/linux/bottom_half.h:32
rcu_read_unlock_bh include/linux/rcupdate.h:739 [inline]
__dev_queue_xmit+0x136e/0x2400 net/core/dev.c:3848
dev_queue_xmit+0x17/0x20 net/core/dev.c:3854
__bpf_tx_skb net/core/filter.c:2063 [inline]
__bpf_redirect_no_mac net/core/filter.c:2097 [inline]
__bpf_redirect+0x699/0xe30 net/core/filter.c:2120
____bpf_clone_redirect net/core/filter.c:2151 [inline]
bpf_clone_redirect+0x242/0x380 net/core/filter.c:2123
bpf_prog_973cd02a7a0e8181+0xde/0x1000
bpf_call_func include/linux/filter.h:627 [inline]
bpf_test_run+0x1ea/0x5d0 net/bpf/test_run.c:44
bpf_prog_test_run_skb+0x721/0xdc0 net/bpf/test_run.c:311
bpf_prog_test_run+0x21a/0x2a0 kernel/bpf/syscall.c:2124
__do_sys_bpf kernel/bpf/syscall.c:2909 [inline]
__se_sys_bpf+0x49a/0x570 kernel/bpf/syscall.c:2849
__x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:2849
do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f3048a7f969
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:00007f30470e8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f3048ca6fa0 RCX: 00007f3048a7f969
RDX: 000000000000002c RSI: 0000200000000080 RDI: 000000000000000a
RBP: 00007f3048b01ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3048ca6fa0 R15: 00007ffd56e2e5a8
Allocated by task 4022:
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
__kasan_kmalloc+0x162/0x200 mm/kasan/common.c:529
kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:537
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc_node mm/slub.c:2829 [inline]
slab_alloc mm/slub.c:2837 [inline]
__kmalloc_track_caller+0x10d/0x2d0 mm/slub.c:4449
__kmalloc_reserve net/core/skbuff.c:142 [inline]
__alloc_skb+0xdc/0x500 net/core/skbuff.c:210
alloc_skb include/linux/skbuff.h:1080 [inline]
nlmsg_new include/net/netlink.h:888 [inline]
fdb_notify+0x78/0x130 net/bridge/br_fdb.c:709
br_fdb_update+0x33d/0x4f0 net/bridge/br_fdb.c:615
br_handle_frame_finish+0x1e6/0x11d0 net/bridge/br_input.c:98
nf_hook_bridge_pre net/bridge/br_input.c:254 [inline]
br_handle_frame+0x407/0x8e0 net/bridge/br_input.c:355
__netif_receive_skb_core+0xe7f/0x2f10 net/core/dev.c:4885
__netif_receive_skb_one_core net/core/dev.c:4989 [inline]
__netif_receive_skb+0x72/0x280 net/core/dev.c:5105
process_backlog+0x363/0x630 net/core/dev.c:5940
napi_poll net/core/dev.c:6386 [inline]
net_rx_action+0x447/0xe50 net/core/dev.c:6454
__do_softirq+0x236/0x660 kernel/softirq.c:292
Freed by task 4022:
save_stack mm/kasan/common.c:70 [inline]
set_track mm/kasan/common.c:78 [inline]
kasan_set_free_info mm/kasan/common.c:345 [inline]
__kasan_slab_free+0x1c3/0x280 mm/kasan/common.c:487
kasan_slab_free+0xe/0x10 mm/kasan/common.c:496
slab_free_hook mm/slub.c:1455 [inline]
slab_free_freelist_hook+0xb7/0x180 mm/slub.c:1494
slab_free mm/slub.c:3080 [inline]
kfree+0xbe/0x260 mm/slub.c:4071
skb_free_head net/core/skbuff.c:601 [inline]
skb_release_data+0x4ea/0x610 net/core/skbuff.c:621
skb_release_all net/core/skbuff.c:675 [inline]
__kfree_skb net/core/skbuff.c:689 [inline]
consume_skb+0xad/0x240 net/core/skbuff.c:849
netlink_broadcast_filtered+0x1198/0x1290 net/netlink/af_netlink.c:1516
netlink_broadcast net/netlink/af_netlink.c:1538 [inline]
nlmsg_multicast include/net/netlink.h:968 [inline]
nlmsg_notify+0xed/0x1b0 net/netlink/af_netlink.c:2510
rtnl_notify+0x9a/0xc0 net/core/rtnetlink.c:737
fdb_notify+0xce/0x130 net/bridge/br_fdb.c:720
br_fdb_update+0x33d/0x4f0 net/bridge/br_fdb.c:615
br_handle_frame_finish+0x1e6/0x11d0 net/bridge/br_input.c:98
nf_hook_bridge_pre net/bridge/br_input.c:254 [inline]
br_handle_frame+0x407/0x8e0 net/bridge/br_input.c:355
__netif_receive_skb_core+0xe7f/0x2f10 net/core/dev.c:4885
__netif_receive_skb_one_core net/core/dev.c:4989 [inline]
__netif_receive_skb+0x72/0x280 net/core/dev.c:5105
process_backlog+0x363/0x630 net/core/dev.c:5940
napi_poll net/core/dev.c:6386 [inline]
net_rx_action+0x447/0xe50 net/core/dev.c:6454
__do_softirq+0x236/0x660 kernel/softirq.c:292
The buggy address belongs to the object at ffff8881ddb93000
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 456 bytes inside of
512-byte region [ffff8881ddb93000, ffff8881ddb93200)
The buggy address belongs to the page:
page:ffffea000776e400 refcount:1 mapcount:0 mapping:ffff8881f5c02500 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c02500
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x152a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL)
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook mm/page_alloc.c:2165 [inline]
prep_new_page+0x35e/0x370 mm/page_alloc.c:2171
get_page_from_freelist+0x1296/0x1310 mm/page_alloc.c:3794
__alloc_pages_nodemask+0x202/0x4b0 mm/page_alloc.c:4894
alloc_slab_page+0x3c/0x3b0 mm/slub.c:343
allocate_slab mm/slub.c:1683 [inline]
new_slab+0x93/0x420 mm/slub.c:1749
new_slab_objects mm/slub.c:2505 [inline]
___slab_alloc+0x29e/0x420 mm/slub.c:2667
__slab_alloc+0x63/0xa0 mm/slub.c:2707
slab_alloc_node mm/slub.c:2792 [inline]
slab_alloc mm/slub.c:2837 [inline]
__kmalloc+0x176/0x2f0 mm/slub.c:3909
kmalloc include/linux/slab.h:561 [inline]
kzalloc include/linux/slab.h:690 [inline]
neigh_alloc net/core/neighbour.c:439 [inline]
___neigh_create+0x6f0/0x1a80 net/core/neighbour.c:592
__neigh_create+0x31/0x40 net/core/neighbour.c:680
ip6_finish_output2+0x934/0x1570 net/ipv6/ip6_output.c:126
__ip6_finish_output+0x5ff/0x790 net/ipv6/ip6_output.c:200
ip6_finish_output+0x33/0x1f0 net/ipv6/ip6_output.c:210
NF_HOOK_COND include/linux/netfilter.h:292 [inline]
ip6_output+0x1bc/0x3a0 net/ipv6/ip6_output.c:233
dst_output include/net/dst.h:438 [inline]
NF_HOOK include/linux/netfilter.h:303 [inline]
ndisc_send_skb+0x71d/0xba0 net/ipv6/ndisc.c:513
ndisc_send_ns+0x842/0xaf0 net/ipv6/ndisc.c:655
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1176 [inline]
__free_pages_ok+0x7e4/0x910 mm/page_alloc.c:1438
free_the_page mm/page_alloc.c:4956 [inline]
__free_pages+0x8c/0x110 mm/page_alloc.c:4962
kfree+0x1ca/0x260 mm/slub.c:4068
kvfree+0x4c/0x50 mm/util.c:625
netdev_freemem+0x3f/0x60 net/core/dev.c:9583
netdev_release+0x7f/0xb0 net/core/net-sysfs.c:1743
device_release+0x70/0x1a0 drivers/base/core.c:1776
kobject_cleanup lib/kobject.c:716 [inline]
kobject_release lib/kobject.c:747 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1fe/0x2c0 lib/kobject.c:764
put_device+0x1f/0x30 drivers/base/core.c:3010
free_netdev+0x27e/0x320 net/core/dev.c:9746
tun_set_iff+0x87c/0xe00 drivers/net/tun.c:2924
__tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187
tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470
do_vfs_ioctl+0x753/0x13f0 fs/ioctl.c:47
ksys_ioctl fs/ioctl.c:742 [inline]
__do_sys_ioctl fs/ioctl.c:749 [inline]
__se_sys_ioctl fs/ioctl.c:747 [inline]
__x64_sys_ioctl+0xe1/0x120 fs/ioctl.c:747
do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
Memory state around the buggy address:
ffff8881ddb93080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881ddb93100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881ddb93180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881ddb93200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881ddb93280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 0 P4D 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010202
RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffffffff85c1ad40
RDX: 0000000080000101 RSI: 0000000000000000 RDI: ffff8881ddb931c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb0c0
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881ddb931c0
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000005c0e000 CR4: 00000000003406b0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600
Call Trace:
call_timer_fn+0x3c/0x380 kernel/time/timer.c:1448
expire_timers kernel/time/timer.c:1493 [inline]
__run_timers+0x81d/0xb60 kernel/time/timer.c:1817
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1830
__do_softirq+0x236/0x660 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x197/0x1c0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:539 [inline]
smp_apic_timer_interrupt+0x11d/0x490 arch/x86/kernel/apic/apic.c:1161
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
RIP: 0010:default_idle+0x23/0x40 arch/x86/kernel/process.c:578
Code: 90 90 00 00 90 90 00 55 48 89 e5 e8 87 b2 f5 fd bf 01 00 00 00 89 c6 e8 bb 1c fc fc 0f 1f 44 00 00 0f 00 2d cf c2 59 00 fb f4 68 b2 f5 fd bf ff ff ff ff 89 c6 e8 9c 1c fc fc 5d c3 66 2e 0f
RSP: 0018:ffffffff85c07cc0 EFLAGS: 000002c6 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff85c1ad40 RCX: ffffffff85c1ad40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffffff85c07cc0 R08: dffffc0000000000 R09: fffffbfff0b835a9
R10: fffffbfff0b835a9 R11: 1ffffffff0b835a8 R12: 0000000000000000
R13: 1ffffffff0b835a8 R14: 0000000000000000 R15: ffffffff862bb528
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:568
default_idle_call kernel/sched/idle.c:94 [inline]
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x21d/0x550 kernel/sched/idle.c:264
cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:356
rest_init+0xe8/0xf0 init/main.c:707
arch_call_rest_init+0xe/0x10 init/main.c:831
start_kernel+0x678/0x73e init/main.c:1036
x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:492
x86_64_start_kernel+0x60/0x63 arch/x86/kernel/head64.c:473
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
Modules linked in:
CR2: 0000000000000000
---[ end trace 5d4b2761df3a91e8 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09cf0 EFLAGS: 00010202
RAX: ffffffff8150a590 RBX: 0000000000000101 RCX: ffffffff85c1ad40
RDX: 0000000080000101 RSI: 0000000000000000 RDI: ffff8881ddb931c0
RBP: ffff8881f6e09d30 R08: 0000000000000004 R09: 0000000000000003
R10: ffffed103edc1398 R11: 1ffff1103edc1398 R12: 00000000ffffb0c0
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881ddb931c0
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000005c0e000 CR4: 00000000003406b0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600
----------------
Code disassembly (best guess):
0: 90 nop
1: 90 nop
2: 00 00 add %al,(%rax)
4: 90 nop
5: 90 nop
6: 00 55 48 add %dl,0x48(%rbp)
9: 89 e5 mov %esp,%ebp
b: e8 87 b2 f5 fd call 0xfdf5b297
10: bf 01 00 00 00 mov $0x1,%edi
15: 89 c6 mov %eax,%esi
17: e8 bb 1c fc fc call 0xfcfc1cd7
1c: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
21: 0f 00 2d cf c2 59 00 verw 0x59c2cf(%rip) # 0x59c2f7
28: fb sti
29: f4 hlt
* 2a: e8 68 b2 f5 fd call 0xfdf5b297 <-- trapping instruction
2f: bf ff ff ff ff mov $0xffffffff,%edi
34: 89 c6 mov %eax,%esi
36: e8 9c 1c fc fc call 0xfcfc1cd7
3b: 5d pop %rbp
3c: c3 ret
3d: 66 data16
3e: 2e cs
3f: 0f .byte 0xf