==================================================================
BUG: KASAN: slab-use-after-free in ax25cmp+0x2bc/0x410 net/ax25/ax25_addr.c:119
Read of size 1 at addr ffff888040df9408 by task swapper/0/0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
ax25cmp+0x2bc/0x410 net/ax25/ax25_addr.c:119
ax25_find_cb+0x130/0x3a0 net/ax25/af_ax25.c:236
ax25_send_frame+0x2f6/0x9f0 net/ax25/ax25_out.c:55
rose_send_frame+0x111/0x220 net/rose/rose_link.c:106
rose_transmit_restart_request net/rose/rose_link.c:198 [inline]
rose_t0timer_expiry+0x143/0x350 net/rose/rose_link.c:83
call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x61a/0x860 kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404
handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x60/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 13 e3 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 73 c1 0e 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07dc0 EFLAGS: 000002c2
RAX: 0000000000396937 RBX: ffffffff819713ee RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d792037 RDI: ffffffff8bc083e0
RBP: ffffffff8dc07eb0 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f822270
R13: 1ffffffff1b92a68 R14: 0000000000000000 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1be/0x4d0 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x381/0x3d0 init/main.c:1206
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
Allocated by task 29925:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5776
kmalloc_noprof include/linux/slab.h:957 [inline]
rose_add_node+0x23a/0xeb0 net/rose/rose_route.c:85
rose_rt_ioctl+0xce2/0x1240 net/rose/rose_route.c:748
rose_ioctl+0x3ce/0x8b0 net/rose/af_rose.c:1382
sock_do_ioctl+0xdc/0x300 net/socket.c:1254
sock_ioctl+0x576/0x790 net/socket.c:1375
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 0:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6670 [inline]
kfree+0x1c0/0x660 mm/slub.c:6878
rose_neigh_put include/net/rose.h:166 [inline]
rose_timer_expiry+0x4cb/0x600 net/rose/rose_timer.c:183
call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x61a/0x860 kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404
handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x60/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
The buggy address belongs to the object at ffff888040df9400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
freed 512-byte region [ffff888040df9400, ffff888040df9600)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x40df8
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ffa6c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ffa6c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0001037e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 29466, tgid 29465 (syz.6.8154), ts 659160576238, free_ts 634860614870
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857
prep_new_page mm/page_alloc.c:1865 [inline]
get_page_from_freelist+0x24e0/0x2580 mm/page_alloc.c:3915
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab+0x86/0x3b0 mm/slub.c:3248
new_slab mm/slub.c:3302 [inline]
___slab_alloc+0xe53/0x1820 mm/slub.c:4656
__slab_alloc+0x65/0x100 mm/slub.c:4779
__slab_alloc_node mm/slub.c:4855 [inline]
slab_alloc_node mm/slub.c:5251 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_noprof+0x47d/0x800 mm/slub.c:5669
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
hash_netportnet6_add+0x2427/0x2e60 net/netfilter/ipset/ip_set_hash_gen.h:950
hash_netportnet6_uadt+0xafa/0xed0 net/netfilter/ipset/ip_set_hash_netportnet.c:560
call_ad+0x383/0xb00 net/netfilter/ipset/ip_set_core.c:1751
ip_set_ad+0x791/0x930 net/netfilter/ipset/ip_set_core.c:1841
nfnetlink_rcv_msg+0xb4d/0x1130 net/netfilter/nfnetlink.c:302
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
nfnetlink_rcv+0x282/0x2590 net/netfilter/nfnetlink.c:669
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
page last free pid 12481 tgid 12481 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
bpf_ringbuf_free kernel/bpf/ringbuf.c:239 [inline]
ringbuf_map_free+0xc9/0x120 kernel/bpf/ringbuf.c:248
bpf_map_free+0x19b/0x3f0 kernel/bpf/syscall.c:894
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Memory state around the buggy address:
ffff888040df9300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888040df9380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888040df9400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888040df9480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888040df9500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 13 e3 adc %ebx,%esp
2: 02 00 add (%rax),%al
4: cc int3
5: cc int3
6: cc int3
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: f3 0f 1e fa endbr64
1b: 66 90 xchg %ax,%ax
1d: 0f 00 2d 73 c1 0e 00 verw 0xec173(%rip) # 0xec197
24: f3 0f 1e fa endbr64
28: fb sti
29: f4 hlt
* 2a: c3 ret <-- trapping instruction
2b: cc int3
2c: cc int3
2d: cc int3
2e: cc int3
2f: cc int3
30: cc int3
31: cc int3
32: cc int3
33: cc int3
34: cc int3
35: cc int3
36: cc int3
37: 90 nop
38: 90 nop
39: 90 nop
3a: 90 nop
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop