[moderation] [kernel?] KASAN: slab-use-after-free Read in ret_from_fork_asm

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2d5404caa8c7 Linux 6.12-rc7
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14a3335f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=327b6119dd928cbc
dashboard link: https://syzkaller.appspot.com/bug?extid=9f32a6e177f4d8959c72
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
CC: [gre...@linuxfoundation.org linux-...@vger.kernel.org raf...@kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-2d5404ca.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1bbbfa50cb5f/vmlinux-2d5404ca.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a5bcdede1c8a/bzImage-2d5404ca.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9f32a6...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in device_for_each_child+0x18f/0x1a0 drivers/base/core.c:3996
Read of size 8 at addr ffff888034441308 by task kbnepd ��4�1./6866

CPU: 1 UID: 0 PID: 6866 Comm: kbnepd ��4�1. Not tainted 6.12.0-rc7-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
unregister_netdevice include/linux/netdevice.h:3118 [inline]
unregister_netdev+0x1c/0x30 net/core/dev.c:11487
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Allocated by task 5949:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kmalloc_noprof include/linux/slab.h:882 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
hci_alloc_dev_priv+0x1d/0x2820 net/bluetooth/hci_core.c:2440
vhci_create_device drivers/bluetooth/hci_vhci.c:470 [inline]
vhci_get_user drivers/bluetooth/hci_vhci.c:527 [inline]
vhci_write+0x2c3/0x470 drivers/bluetooth/hci_vhci.c:607
ksys_write+0x12f/0x260 fs/read_write.c:736
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 7103:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:2342 [inline]
slab_free mm/slub.c:4579 [inline]
kfree+0x14f/0x4b0 mm/slub.c:4727
hci_release_dev+0x4d9/0x600 net/bluetooth/hci_core.c:2759
bt_host_release+0x6a/0xb0 net/bluetooth/hci_sysfs.c:94
device_release+0xa1/0x240 drivers/base/core.c:2574
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1e4/0x5a0 lib/kobject.c:737
put_device+0x1f/0x30 drivers/base/core.c:3780
vhci_release+0x81/0xf0 drivers/bluetooth/hci_vhci.c:665
__fput+0x3f6/0xb60 fs/file_table.c:431
arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337
do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
insert_work+0x36/0x230 kernel/workqueue.c:2183
queue_work_on+0x11a/0x140 kernel/workqueue.c:2390
queue_work include/linux/workqueue.h:662 [inline]
hci_recv_frame+0x23f/0x7e0 net/bluetooth/hci_core.c:2946
vhci_get_user drivers/bluetooth/hci_vhci.c:511 [inline]
vhci_write+0x385/0x470 drivers/bluetooth/hci_vhci.c:607
new_sync_write fs/read_write.c:590 [inline]
vfs_write+0x5ae/0x1150 fs/read_write.c:683
ksys_write+0x12f/0x260 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
queue_work include/linux/workqueue.h:662 [inline]
hci_recv_frame+0x23f/0x7e0 net/bluetooth/hci_core.c:2946
vhci_get_user drivers/bluetooth/hci_vhci.c:511 [inline]
vhci_write+0x385/0x470 drivers/bluetooth/hci_vhci.c:607
The buggy address belongs to the object at ffff888034440000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 4872 bytes inside of
freed 8192-byte region [ffff888034440000, ffff888034442000)

head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
page_type: f5(slab)
raw: 0000000000000000 0000000000020002 00000001f5000000 0000000000000000
head: 0000000000000000 0000000000020002 00000001f5000000 0000000000000000
head: 00fff00000000003 ffffea0000d11001 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5644, tgid 5644 (S35iptables), ts 20304618083, free_ts 20294994496
___slab_alloc+0xdac/0x1880 mm/slub.c:3818
tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
tomoyo_env_perm+0x193/0x210 security/tomoyo/environ.c:63
tomoyo_bprm_check_security security/tomoyo/tomoyo.c:102 [inline]
tomoyo_bprm_check_security+0x12b/0x1d0 security/tomoyo/tomoyo.c:92
security_bprm_check+0x1b9/0x1e0 security/security.c:1297
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
do_sys_open fs/open.c:1430 [inline]
__do_sys_openat fs/open.c:1446 [inline]
__se_sys_openat fs/open.c:1441 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1441
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
>ffff888034441300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034441380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.