* [syzbot] [hams?] KASAN: slab-use-after-free Read in ax25_send_frame (3)
@ 2026-04-27 9:11 syzbot
0 siblings, 0 replies; only message in thread
From: syzbot @ 2026-04-27 9:11 UTC (permalink / raw)
To: davem, edumazet, horms, jreuter, kuba, linux-hams, linux-kernel,
netdev, pabeni, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: e728258debd5 Merge tag 'net-7.1-rc1' of git://git.kernel.o..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15d109ba580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ca77bfc4078c8193
dashboard link: https://syzkaller.appspot.com/bug?extid=9c8999af06ca7df15fc6
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/24195bde5d1d/disk-e728258d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/78131d1b0e14/vmlinux-e728258d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/836d0dd78c10/bzImage-e728258d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9c8999af06ca7df15fc6@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in kmemdup_noprof+0x55/0x70 mm/util.c:140
Read of size 66 at addr ffff8880310ac600 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 04/18/2026
Call Trace:
<IRQ>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
__asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
kmemdup_noprof+0x55/0x70 mm/util.c:140
kmemdup_noprof include/linux/fortify-string.h:763 [inline]
ax25_send_frame+0x693/0x9f0 net/ax25/ax25_out.c:78
rose_send_frame net/rose/rose_link.c:106 [inline]
rose_transmit_restart_request net/rose/rose_link.c:198 [inline]
rose_t0timer_expiry+0x255/0x560 net/rose/rose_link.c:83
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: db 70 02 e9 53 f4 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 13 81 10 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8e607dc0 EFLAGS: 00000242
RAX: 0000000000110dc7 RBX: ffffffff819aae9a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfd8f45 RDI: ffffffff8c289f60
RBP: ffffffff8e607eb0 R08: ffff8880b86339db R09: 1ffff110170c673b
R10: dffffc0000000000 R11: ffffed10170c673c R12: 0000000000000000
R13: 1ffffffff1cd25d8 R14: 0000000000000000 R15: 1ffffffff1cd25d8
arch_safe_halt arch/x86/kernel/process.c:766 [inline]
default_idle+0x9/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x36a/0x5f0 kernel/sched/idle.c:352
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451
rest_init+0x2de/0x300 init/main.c:762
start_kernel+0x38a/0x3e0 init/main.c:1220
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
</TASK>
Allocated by task 10474:
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+0x31c/0x660 mm/slub.c:5415
kmalloc_noprof include/linux/slab.h:950 [inline]
rose_add_node+0x471/0xf00 net/rose/rose_route.c:109
rose_rt_ioctl+0xd35/0x12a0 net/rose/rose_route.c:748
rose_ioctl+0x3fb/0x8f0 net/rose/af_rose.c:1387
sock_do_ioctl+0x101/0x320 net/socket.c:1313
sock_ioctl+0x5c6/0x7f0 net/socket.c:1434
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+0x15f/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:2689 [inline]
slab_free mm/slub.c:6246 [inline]
kfree+0x1c5/0x640 mm/slub.c:6561
rose_neigh_put include/net/rose.h:165 [inline]
rose_timer_expiry+0x4c3/0x600 net/rose/rose_timer.c:183
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
The buggy address belongs to the object at ffff8880310ac600
which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
freed 96-byte region [ffff8880310ac600, ffff8880310ac660)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x310ac
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88813fe2e280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 22916083211, free_ts 22905974702
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
prep_new_page mm/page_alloc.c:1866 [inline]
get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
alloc_slab_page mm/slub.c:3278 [inline]
allocate_slab+0x77/0x660 mm/slub.c:3467
new_slab mm/slub.c:3525 [inline]
refill_objects+0x339/0x3d0 mm/slub.c:7251
refill_sheaf mm/slub.c:2816 [inline]
__pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651
alloc_from_pcs mm/slub.c:4749 [inline]
slab_alloc_node mm/slub.c:4883 [inline]
__kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5410
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
lookup_or_create_module_kobject+0x75/0x170 kernel/params.c:759
module_add_driver+0x79/0x320 drivers/base/module.c:46
bus_add_driver+0x391/0x670 drivers/base/bus.c:760
driver_register+0x23a/0x320 drivers/base/driver.c:249
usb_register_driver+0x1e4/0x390 drivers/usb/core/driver.c:1078
do_one_initcall+0x250/0x870 init/main.c:1392
do_initcall_level+0x104/0x190 init/main.c:1454
do_initcalls+0x59/0xa0 init/main.c:1470
kernel_init_freeable+0x2a6/0x3e0 init/main.c:1703
page last free pid 1 tgid 1 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1402 [inline]
__free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943
vfree+0x1d1/0x2f0 mm/vmalloc.c:3472
tpg_free+0x3aa/0x430 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:202
vivid_dev_release+0xc5/0x120 drivers/media/test-drivers/vivid/vivid-core.c:865
v4l2_device_release drivers/media/v4l2-core/v4l2-device.c:51 [inline]
kref_put include/linux/kref.h:65 [inline]
v4l2_device_put+0x81/0xd0 drivers/media/v4l2-core/v4l2-device.c:56
vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:2070 [inline]
vivid_probe+0x4a4a/0x72b0 drivers/media/test-drivers/vivid/vivid-core.c:2095
platform_probe+0xf9/0x190 drivers/base/platform.c:1418
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x267/0xaf0 drivers/base/dd.c:709
__driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
__driver_attach+0x34c/0x640 drivers/base/dd.c:1295
bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383
bus_add_driver+0x345/0x670 drivers/base/bus.c:756
driver_register+0x23a/0x320 drivers/base/driver.c:249
vivid_init+0x561/0x5f0 drivers/media/test-drivers/vivid/vivid-core.c:2294
do_one_initcall+0x250/0x870 init/main.c:1392
Memory state around the buggy address:
ffff8880310ac500: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
ffff8880310ac580: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff8880310ac600: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
^
ffff8880310ac680: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
ffff8880310ac700: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
0: db 70 02 (bad) 0x2(%rax)
3: e9 53 f4 02 00 jmp 0x2f45b
8: cc int3
9: cc int3
a: cc int3
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: 90 nop
18: 90 nop
19: 90 nop
1a: 90 nop
1b: f3 0f 1e fa endbr64
1f: 66 90 xchg %ax,%ax
21: 0f 00 2d 13 81 10 00 verw 0x108113(%rip) # 0x10813b
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: cc int3
38: cc int3
39: cc int3
3a: cc int3
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop
---
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