From: syzbot <syzbot+fed5dce4553262f3b35c@syzkaller.appspotmail.com>
To: dakr@kernel.org, driver-core@lists.linux.dev,
gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
rafael@kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [kernel?] KASAN: slab-use-after-free Read in netdev_register_kobject (2)
Date: Mon, 01 Jun 2026 08:08:24 -0700 [thread overview]
Message-ID: <6a1da068.bd48a97d.14881d.0003.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: 4cbfe4502e3d Merge tag 'v7.1-rc5-ksmbd-server-fixes' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11419cec580000
kernel config: https://syzkaller.appspot.com/x/.config?x=58acee1ac5406016
dashboard link: https://syzkaller.appspot.com/bug?extid=fed5dce4553262f3b35c
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-4cbfe450.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/45e57d38df99/vmlinux-4cbfe450.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fe2428a7711a/bzImage-4cbfe450.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fed5dce4553262f3b35c@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in kobject_get+0x136/0x150 lib/kobject.c:639
Read of size 1 at addr ffff88804be10d1c by task syz.2.2484/16757
CPU: 1 UID: 0 PID: 16757 Comm: syz.2.2484 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1d0 mm/kasan/report.c:595
kobject_get+0x136/0x150 lib/kobject.c:639
get_device drivers/base/core.c:3802 [inline]
device_add+0x19f/0x1950 drivers/base/core.c:3614
netdev_register_kobject+0x1a9/0x3d0 net/core/net-sysfs.c:2343
register_netdevice+0x151c/0x24b0 net/core/dev.c:11423
register_netdev+0x34/0x50 net/core/dev.c:11539
bnep_add_connection+0x723/0xd30 net/bluetooth/bnep/core.c:631
do_bnep_sock_ioctl.isra.0+0x3ac/0x5b0 net/bluetooth/bnep/sock.c:83
bnep_sock_compat_ioctl+0x87/0x1d0 net/bluetooth/bnep/sock.c:168
compat_sock_ioctl+0x179/0x760 net/socket.c:3632
__do_compat_sys_ioctl fs/ioctl.c:695 [inline]
__se_compat_sys_ioctl fs/ioctl.c:638 [inline]
__ia32_compat_sys_ioctl+0x2cf/0x360 fs/ioctl.c:638
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307
do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf705ef7c
Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 2e 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 58 b8
RSP: 002b:00000000f540b50c EFLAGS: 00000292 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00000000400442c8
RDX: 0000000080000340 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Allocated by task 12930:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__hci_conn_add+0x1f4/0x1da0 net/bluetooth/hci_conn.c:1030
hci_conn_add_unset+0x76/0x120 net/bluetooth/hci_conn.c:1157
hci_conn_request_evt+0xa58/0xbb0 net/bluetooth/hci_event.c:3333
hci_event_func net/bluetooth/hci_event.c:7796 [inline]
hci_event_packet+0x8e9/0xcd0 net/bluetooth/hci_event.c:7847
hci_rx_work+0x451/0xfc0 net/bluetooth/hci_core.c:4077
process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
process_scheduled_works kernel/workqueue.c:3397 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Freed by task 16742:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/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:6251 [inline]
kfree+0x223/0x6c0 mm/slub.c:6566
device_release+0xd2/0x270 drivers/base/core.c:2566
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1f7/0x640 lib/kobject.c:737
put_device+0x1f/0x30 drivers/base/core.c:3814
hci_conn_put include/net/bluetooth/hci_core.h:1673 [inline]
hci_disconnect_all_sync.constprop.0.isra.0+0x15d/0x430 net/bluetooth/hci_sync.c:5790
hci_suspend_sync+0x8b7/0xa70 net/bluetooth/hci_sync.c:6265
hci_suspend_dev+0x31d/0x540 net/bluetooth/hci_core.c:2850
hci_suspend_notifier+0x21e/0x330 net/bluetooth/hci_core.c:2421
notifier_call_chain+0x99/0x400 kernel/notifier.c:85
notifier_call_chain_robust kernel/notifier.c:120 [inline]
blocking_notifier_call_chain_robust kernel/notifier.c:345 [inline]
blocking_notifier_call_chain_robust+0xc8/0x160 kernel/notifier.c:333
pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:172
snapshot_open+0x189/0x2a0 kernel/power/user.c:77
misc_open+0x26d/0x450 drivers/char/misc.c:163
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6d8/0x1660 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4858
do_file_open+0x20e/0x430 fs/namei.c:4887
do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_compat_sys_openat fs/open.c:1432 [inline]
__se_compat_sys_openat fs/open.c:1430 [inline]
__ia32_compat_sys_openat+0x12d/0x210 fs/open.c:1430
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307
do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
Last potentially related work creation:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
insert_work+0x36/0x230 kernel/workqueue.c:2226
__queue_work+0x9a2/0x1270 kernel/workqueue.c:2393
__queue_delayed_work+0x357/0x450 kernel/workqueue.c:2560
queue_delayed_work_on+0x180/0x1e0 kernel/workqueue.c:2612
queue_delayed_work include/linux/workqueue.h:713 [inline]
hci_conn_drop include/net/bluetooth/hci_core.h:1712 [inline]
hci_conn_drop include/net/bluetooth/hci_core.h:1686 [inline]
l2cap_chan_del+0x649/0x930 net/bluetooth/l2cap_core.c:672
l2cap_conn_del+0x395/0x710 net/bluetooth/l2cap_core.c:1802
l2cap_connect_cfm+0x9bb/0xf80 net/bluetooth/l2cap_core.c:7374
hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]
hci_conn_failed+0x188/0x360 net/bluetooth/hci_conn.c:1409
hci_abort_conn_sync+0x7d9/0xb20 net/bluetooth/hci_sync.c:5766
hci_disconnect_all_sync.constprop.0.isra.0+0x155/0x430 net/bluetooth/hci_sync.c:5789
hci_suspend_sync+0x8b7/0xa70 net/bluetooth/hci_sync.c:6265
hci_suspend_dev+0x31d/0x540 net/bluetooth/hci_core.c:2850
hci_suspend_notifier+0x21e/0x330 net/bluetooth/hci_core.c:2421
notifier_call_chain+0x99/0x400 kernel/notifier.c:85
notifier_call_chain_robust kernel/notifier.c:120 [inline]
blocking_notifier_call_chain_robust kernel/notifier.c:345 [inline]
blocking_notifier_call_chain_robust+0xc8/0x160 kernel/notifier.c:333
pm_notifier_call_chain_robust+0x27/0x60 kernel/power/main.c:172
snapshot_open+0x189/0x2a0 kernel/power/user.c:77
misc_open+0x26d/0x450 drivers/char/misc.c:163
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6d8/0x1660 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4858
do_file_open+0x20e/0x430 fs/namei.c:4887
do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_compat_sys_openat fs/open.c:1432 [inline]
__se_compat_sys_openat fs/open.c:1430 [inline]
__ia32_compat_sys_openat+0x12d/0x210 fs/open.c:1430
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307
do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
The buggy address belongs to the object at ffff88804be10000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 3356 bytes inside of
freed 8192-byte region [ffff88804be10000, ffff88804be12000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88804be14000 pfn:0x4be10
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000240(workingset|head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000240 ffff88801b843180 ffffea00012f7c10 ffffea000132a210
raw: ffff88804be14000 0000000800020001 00000000f5000000 0000000000000000
head: 04fff00000000240 ffff88801b843180 ffffea00012f7c10 ffffea000132a210
head: ffff88804be14000 0000000800020001 00000000f5000000 0000000000000000
head: 04fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 16670, tgid 16669 (syz.3.2439), ts 1231348900296, free_ts 1230410524617
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1858
prep_new_page mm/page_alloc.c:1866 [inline]
get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226
alloc_slab_page mm/slub.c:3278 [inline]
allocate_slab mm/slub.c:3467 [inline]
new_slab+0xa6/0x6c0 mm/slub.c:3525
refill_objects+0x277/0x420 mm/slub.c:7272
refill_sheaf mm/slub.c:2816 [inline]
__pcs_replace_empty_main+0x375/0x650 mm/slub.c:4652
alloc_from_pcs mm/slub.c:4750 [inline]
slab_alloc_node mm/slub.c:4884 [inline]
__do_kmalloc_node mm/slub.c:5295 [inline]
__kmalloc_noprof+0x688/0x850 mm/slub.c:5308
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
snd_seq_oss_readq_new+0x9b/0x290 sound/core/seq/oss/seq_oss_readq.c:41
snd_seq_oss_open+0x476/0xa10 sound/core/seq/oss/seq_oss_init.c:226
odev_open+0x6f/0x90 sound/core/seq/oss/seq_oss.c:128
soundcore_open+0x2e3/0x5a0 sound/sound_core.c:594
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6d8/0x1660 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4858
do_file_open+0x20e/0x430 fs/namei.c:4887
page last free pid 16136 tgid 16136 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1402 [inline]
__free_frozen_pages+0x747/0x1040 mm/page_alloc.c:2943
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4570 [inline]
slab_alloc_node mm/slub.c:4899 [inline]
__do_kmalloc_node mm/slub.c:5295 [inline]
__kvmalloc_node_noprof+0x316/0xa00 mm/slub.c:6833
xt_alloc_table_info+0x44/0xa0 net/netfilter/x_tables.c:1286
compat_do_replace+0x19b/0x500 net/ipv4/netfilter/ip_tables.c:1514
do_ip6t_set_ctl+0x562/0xb00 net/ipv6/netfilter/ip6_tables.c:1641
nf_setsockopt+0x8d/0xf0 net/netfilter/nf_sockopt.c:101
ipv6_setsockopt+0x135/0x170 net/ipv6/ipv6_sockglue.c:970
tcp_setsockopt+0xa7/0x100 net/ipv4/tcp.c:4182
do_sock_setsockopt+0xf3/0x1d0 net/socket.c:2381
__sys_setsockopt+0x119/0x190 net/socket.c:2406
__do_compat_sys_socketcall net/compat.c:491 [inline]
__se_compat_sys_socketcall net/compat.c:423 [inline]
__ia32_compat_sys_socketcall+0x556/0x770 net/compat.c:423
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307
do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
Memory state around the buggy address:
ffff88804be10c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88804be10c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88804be10d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88804be10d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88804be10e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: d2 74 05 c1 shlb %cl,-0x3f(%rbp,%rax,1)
4: e8 0c 89 02 8b call 0x8b028915
9: 5d pop %rbp
a: fc cld
b: 31 c0 xor %eax,%eax
d: c9 leave
e: c3 ret
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: 90 nop
1c: 90 nop
1d: 90 nop
1e: 0f 1f 00 nopl (%rax)
21: 51 push %rcx
22: 52 push %rdx
23: 55 push %rbp
24: 89 e5 mov %esp,%ebp
26: 0f 34 sysenter
28: cd 80 int $0x80
* 2a: 5d pop %rbp <-- trapping instruction
2b: 5a pop %rdx
2c: 59 pop %rcx
2d: c3 ret
2e: 90 nop
2f: 2e 8d b4 26 00 00 00 cs lea 0x0(%rsi,%riz,1),%esi
36: 00
37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
3e: 58 pop %rax
3f: b8 .byte 0xb8
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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reply other threads:[~2026-06-01 15:08 UTC|newest]
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