==================================================================
BUG: KASAN: use-after-free in ax25_send_frame+0x678/0x9f0 net/ax25/ax25_out.c:75
Read of size 7 at addr ffff8880575f7008 by task udevd/6499
CPU: 1 PID: 6499 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
print_address_description mm/kasan/report.c:316 [inline]
print_report+0xa8/0x210 mm/kasan/report.c:420
kasan_report+0x10b/0x140 mm/kasan/report.c:524
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x235/0x290 mm/kasan/generic.c:189
memcpy+0x25/0x60 mm/kasan/shadow.c:65
ax25_send_frame+0x678/0x9f0 net/ax25/ax25_out.c:75
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+0x13f/0x350 net/rose/rose_link.c:83
call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x53e/0x800 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 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
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:get_stack_info_noinstr+0x8/0x130 arch/x86/kernel/dumpstack_64.c:172
Code: 48 c7 c7 40 40 86 8a e8 96 3b 00 00 65 c6 05 0e d0 d4 75 00 eb 9b 00 00 cc cc 00 00 cc cc 00 00 cc cc 41 57 41 56 41 55 41 54 <53> 49 89 d6 49 89 f4 49 89 ff e8 19 01 00 00 b3 01 84 c0 0f 85 d0
RSP: 0018:ffffc9000e2cf810 EFLAGS: 00000282
RAX: 1ffff92001c59f20 RBX: ffffc9000e2cf8e8 RCX: ffffc9000e2cf8e8
RDX: ffffc9000e2cf8c8 RSI: ffff888028bb1dc0 RDI: ffffc9000e2cf868
RBP: ffffc9000e2cf901 R08: ffffc9000e2cf927 R09: ffffc9000e2cf8c8
R10: dffffc0000000000 R11: fffff52001c59f25 R12: ffffc9000e2cf868
R13: ffffc9000e2cf8e8 R14: ffffc9000e2cf8c8 R15: ffff888028bb1dc0
get_stack_info+0x36/0xf0 arch/x86/kernel/dumpstack_64.c:199
__unwind_start+0x441/0x740 arch/x86/kernel/unwind_orc.c:686
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xda/0x140 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
__kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700
kernfs_fop_release+0x162/0x190 fs/kernfs/file.c:828
__fput+0x22c/0x920 fs/file_table.c:320
task_work_run+0x1d0/0x260 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f09bcca7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffdc7569750 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f09bd35c880 RCX: 00007f09bcca7407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055c34689c7c0
R13: 0000000000000005 R14: 00007ffdc7569c30 R15: 000055c337e5fbcc
Allocated by task 4509:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
kmalloc include/linux/slab.h:563 [inline]
rose_add_node+0x227/0xea0 net/rose/rose_route.c:85
rose_rt_ioctl+0xb63/0xf70 net/rose/rose_route.c:748
rose_ioctl+0x2a7/0x7d0 net/rose/af_rose.c:1386
sock_do_ioctl+0xfb/0x320 net/socket.c:1201
sock_ioctl+0x4d2/0x710 net/socket.c:1320
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Freed by task 7996:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
__kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700
rose_neigh_put include/net/rose.h:166 [inline]
rose_timer_expiry+0x4a7/0x5d0 net/rose/rose_timer.c:183
call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x53e/0x800 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 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
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
The buggy address belongs to the object at ffff8880575f7000
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
512-byte region [ffff8880575f7000, ffff8880575f7200)
The buggy address belongs to the physical page:
page:ffffea00015d7d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x575f4
head:ffffea00015d7d00 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888017441c80
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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4281, tgid 4281 (syz-executor), ts 71602439923, free_ts 19570030102
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
prep_new_page mm/page_alloc.c:2566 [inline]
get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
__alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5657
alloc_slab_page+0x5d/0x160 mm/slub.c:1799
allocate_slab mm/slub.c:1944 [inline]
new_slab+0x87/0x2c0 mm/slub.c:1997
___slab_alloc+0xbc6/0x1240 mm/slub.c:3154
__slab_alloc mm/slub.c:3240 [inline]
slab_alloc_node mm/slub.c:3325 [inline]
__kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398
__do_kmalloc_node mm/slab_common.c:935 [inline]
__kmalloc_node_track_caller+0x9e/0x230 mm/slab_common.c:956
kmalloc_reserve net/core/skbuff.c:446 [inline]
__alloc_skb+0x22a/0x7e0 net/core/skbuff.c:515
alloc_skb include/linux/skbuff.h:1303 [inline]
nlmsg_new include/net/netlink.h:991 [inline]
mpls_netconf_notify_devconf+0x46/0xf0 net/mpls/af_mpls.c:1188
mpls_dev_sysctl_register+0x249/0x2f0 net/mpls/af_mpls.c:1425
mpls_add_dev net/mpls/af_mpls.c:1476 [inline]
mpls_dev_notify+0x24e/0x760 net/mpls/af_mpls.c:1616
notifier_call_chain kernel/notifier.c:87 [inline]
raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
call_netdevice_notifiers_extack net/core/dev.c:2052 [inline]
call_netdevice_notifiers net/core/dev.c:2066 [inline]
register_netdevice+0x163f/0x1b00 net/core/dev.c:10263
veth_newlink+0x830/0xc80 drivers/net/veth.c:1756
rtnl_newlink_create net/core/rtnetlink.c:3422 [inline]
__rtnl_newlink net/core/rtnetlink.c:3642 [inline]
rtnl_newlink+0x1542/0x2080 net/core/rtnetlink.c:3655
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1486 [inline]
free_pcp_prepare mm/page_alloc.c:1536 [inline]
free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413
free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3508
free_contig_range+0x9d/0x150 mm/page_alloc.c:9625
destroy_args+0xf0/0xa0a mm/debug_vm_pgtable.c:1031
debug_vm_pgtable+0x33c/0x38e mm/debug_vm_pgtable.c:1359
do_one_initcall+0x26a/0x840 init/main.c:1310
do_initcall_level+0x137/0x1e4 init/main.c:1383
do_initcalls+0x4b/0x8a init/main.c:1399
kernel_init_freeable+0x415/0x5be init/main.c:1638
kernel_init+0x19/0x1b0 init/main.c:1526
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Memory state around the buggy address:
ffff8880575f6f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880575f6f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880575f7000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880575f7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880575f7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 48 c7 c7 40 40 86 8a mov $0xffffffff8a864040,%rdi
7: e8 96 3b 00 00 call 0x3ba2
c: 65 c6 05 0e d0 d4 75 movb $0x0,%gs:0x75d4d00e(%rip) # 0x75d4d022
13: 00
14: eb 9b jmp 0xffffffb1
16: 00 00 add %al,(%rax)
18: cc int3
19: cc int3
1a: 00 00 add %al,(%rax)
1c: cc int3
1d: cc int3
1e: 00 00 add %al,(%rax)
20: cc int3
21: cc int3
22: 41 57 push %r15
24: 41 56 push %r14
26: 41 55 push %r13
28: 41 54 push %r12
* 2a: 53 push %rbx <-- trapping instruction
2b: 49 89 d6 mov %rdx,%r14
2e: 49 89 f4 mov %rsi,%r12
31: 49 89 ff mov %rdi,%r15
34: e8 19 01 00 00 call 0x152
39: b3 01 mov $0x1,%bl
3b: 84 c0 test %al,%al
3d: 0f .byte 0xf
3e: 85 d0 test %edx,%eax