==================================================================
BUG: KASAN: use-after-free in ax25_send_control+0x70/0x430 net/ax25/ax25_subr.c:152
Read of size 8 at addr ffff0000c1837608 by task syz.3.772/7036
CPU: 0 PID: 7036 Comm: syz.3.772 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0x174/0x1e4 mm/kasan/report.c:451
__asan_report_load8_noabort+0x44/0x50 mm/kasan/report_generic.c:309
ax25_send_control+0x70/0x430 net/ax25/ax25_subr.c:152
ax25_release+0x32c/0x82c net/ax25/af_ax25.c:1006
__sock_release net/socket.c:649 [inline]
sock_close+0xb8/0x1fc net/socket.c:1336
__fput+0x1c4/0x800 fs/file_table.c:311
____fput+0x20/0x30 fs/file_table.c:339
task_work_run+0x130/0x1e4 kernel/task_work.c:188
get_signal+0x1450/0x1550 kernel/signal.c:2672
do_signal arch/arm64/kernel/signal.c:890 [inline]
do_notify_resume+0x3d0/0x32b8 arch/arm64/kernel/signal.c:943
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Allocated by task 4178:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513
__kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522
kasan_kmalloc include/linux/kasan.h:264 [inline]
kmem_cache_alloc_trace+0x27c/0x47c mm/slub.c:3247
kmalloc include/linux/slab.h:591 [inline]
kzalloc include/linux/slab.h:721 [inline]
ax25_dev_device_up+0x5c/0x548 net/ax25/ax25_dev.c:55
ax25_device_event+0x504/0x590 net/ax25/af_ax25.c:139
notifier_call_chain kernel/notifier.c:83 [inline]
raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391
__dev_notify_flags+0x2b4/0x540
dev_change_flags+0xc8/0x154 net/core/dev.c:8928
dev_ifsioc+0x140/0xfe4 net/core/dev_ioctl.c:324
dev_ioctl+0x4e0/0xd3c net/core/dev_ioctl.c:587
sock_do_ioctl+0x1dc/0x2dc net/socket.c:1154
sock_ioctl+0x4f4/0x8b0 net/socket.c:1257
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Freed by task 7019:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4c/0x84 mm/kasan/common.c:46
kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360
____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366
__kasan_slab_free+0x18/0x28 mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1705 [inline]
slab_free_freelist_hook+0x128/0x1ec mm/slub.c:1731
slab_free mm/slub.c:3499 [inline]
kfree+0x178/0x410 mm/slub.c:4559
ax25_dev_put include/net/ax25.h:302 [inline]
ax25_release+0x57c/0x82c net/ax25/af_ax25.c:1062
__sock_release net/socket.c:649 [inline]
sock_close+0xb8/0x1fc net/socket.c:1336
__fput+0x1c4/0x800 fs/file_table.c:311
____fput+0x20/0x30 fs/file_table.c:339
task_work_run+0x130/0x1e4 kernel/task_work.c:188
get_signal+0x1450/0x1550 kernel/signal.c:2672
do_signal arch/arm64/kernel/signal.c:890 [inline]
do_notify_resume+0x3d0/0x32b8 arch/arm64/kernel/signal.c:943
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Last potentially related work creation:
kasan_save_stack+0x38/0x68 mm/kasan/common.c:38
kasan_record_aux_stack+0xd4/0x11c mm/kasan/generic.c:348
insert_work+0x64/0x394 kernel/workqueue.c:1366
__queue_work+0xb84/0x114c kernel/workqueue.c:1532
queue_work_on+0xc4/0x17c kernel/workqueue.c:1559
queue_work include/linux/workqueue.h:512 [inline]
call_usermodehelper_exec+0x238/0x484 kernel/umh.c:435
call_modprobe kernel/kmod.c:98 [inline]
__request_module+0x4c0/0xb34 kernel/kmod.c:170
dev_load+0x1d8/0x1ec net/core/dev_ioctl.c:448
dev_ioctl+0x3a4/0xd3c net/core/dev_ioctl.c:511
sock_do_ioctl+0x1dc/0x2dc net/socket.c:1154
sock_ioctl+0x4f4/0x8b0 net/socket.c:1257
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
The buggy address belongs to the object at ffff0000c1837600
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 8 bytes inside of
256-byte region [ffff0000c1837600, ffff0000c1837700)
The buggy address belongs to the page:
page:0000000081eb41a6 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x101836
head:0000000081eb41a6 order:1 compound_mapcount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc0003050a00 0000000900000009 ffff0000c0002480
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff0000c1837500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000c1837580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000c1837600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000c1837680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000c1837700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Unable to handle kernel paging request at virtual address f0ff8081c0000388
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
[f0ff8081c0000388] address between user and kernel address ranges
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 7036 Comm: syz.3.772 Tainted: G B 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ax25_send_control+0x84/0x430 net/ax25/ax25_subr.c:152
lr : ax25_send_control+0x70/0x430 net/ax25/ax25_subr.c:152
sp : ffff800020b877e0
x29: ffff800020b877e0 x28: dfff800000000000 x27: ffff0000ce0ed080
x26: 1fffe0001aaad005 x25: dfff800000000000 x24: ffff0000d5568028
x23: 0000000000000043 x22: 0000000000000001 x21: 8800040e00001c41
x20: ffff0000d5568000 x19: 0000000000000001 x18: 1fffe0003682e78e
x17: 1fffe0003682e78e x16: ffff800011b59ca8 x15: ffff800014c0f2a0
x14: ffff0001b4173c80 x13: ffff0001b4173c7c x12: 0000000000080000
x11: 0000000000029b16 x10: ffff8000245a9000 x9 : 0000000000000002
x8 : 11000081c0000388 x7 : 0000000000000000 x6 : ffff80000826b1e8
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff80000819cb88
x2 : 0000000000000001 x1 : 0000000000000001 x0 : 0000000000000001
Call trace:
ax25_send_control+0x84/0x430 net/ax25/ax25_subr.c:152
ax25_release+0x32c/0x82c net/ax25/af_ax25.c:1006
__sock_release net/socket.c:649 [inline]
sock_close+0xb8/0x1fc net/socket.c:1336
__fput+0x1c4/0x800 fs/file_table.c:311
____fput+0x20/0x30 fs/file_table.c:339
task_work_run+0x130/0x1e4 kernel/task_work.c:188
get_signal+0x1450/0x1550 kernel/signal.c:2672
do_signal arch/arm64/kernel/signal.c:890 [inline]
do_notify_resume+0x3d0/0x32b8 arch/arm64/kernel/signal.c:943
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: 91035915 d343fea8 12000aa9 11000529 (38f96908)
---[ end trace 1b87fb46178d15d3 ]---
----------------
Code disassembly (best guess):
0: 91035915 add x21, x8, #0xd6
4: d343fea8 lsr x8, x21, #3
8: 12000aa9 and w9, w21, #0x7
c: 11000529 add w9, w9, #0x1
* 10: 38f96908 ldrsb w8, [x8, x25] <-- trapping instruction