[syzbot] [pm?] KASAN: use-after-free Read in netdev_unregister_kobject

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3cdb45594619 Merge tag 's390-6.9-4' of git://git.kernel.or..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13d23353180000
kernel config: https://syzkaller.appspot.com/x/.config?x=d239903bd07761e5
dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=172afcbf180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=144067cb180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5135044ea611/disk-3cdb4559.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3c5a5ab80ba8/vmlinux-3cdb4559.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e215eb6531dd/bzImage-3cdb4559.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6cf565...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in device_for_each_child+0xa7/0x170 drivers/base/core.c:4044
Read of size 8 at addr ffff88807bee95f8 by task kbnepd bnep0/5202

CPU: 0 PID: 5202 Comm: kbnepd bnep0 Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
device_for_each_child+0xa7/0x170 drivers/base/core.c:4044
pm_runtime_set_memalloc_noio+0x114/0x260 drivers/base/power/runtime.c:248
netdev_unregister_kobject+0x178/0x250 net/core/net-sysfs.c:2106
unregister_netdevice_many_notify+0x11dd/0x16e0 net/core/dev.c:11135
unregister_netdevice_many net/core/dev.c:11163 [inline]
unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11042
unregister_netdevice include/linux/netdevice.h:3115 [inline]
unregister_netdev+0x1c/0x30 net/core/dev.c:11181
bnep_session+0x2e09/0x3000 net/bluetooth/bnep/core.c:525
kthread+0x2f2/0x390 kernel/kthread.c:388
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x400000000 pfn:0x7bee9
flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000400000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), pid 5095, tgid -432259438 (syz-executor223), ts 5095, free_ts 96070220809
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
prep_new_page mm/page_alloc.c:1541 [inline]
get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
__alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
__kmalloc_large_node+0x91/0x1f0 mm/slub.c:3911
__do_kmalloc_node mm/slub.c:3954 [inline]
__kmalloc+0x320/0x4a0 mm/slub.c:3979
kmalloc include/linux/slab.h:632 [inline]
kzalloc include/linux/slab.h:749 [inline]
hci_alloc_dev_priv+0x27/0x2030 net/bluetooth/hci_core.c:2500
hci_alloc_dev include/net/bluetooth/hci_core.h:1672 [inline]
__vhci_create_device drivers/bluetooth/hci_vhci.c:406 [inline]
vhci_create_device+0x12e/0x720 drivers/bluetooth/hci_vhci.c:480
vhci_get_user drivers/bluetooth/hci_vhci.c:537 [inline]
vhci_write+0x3cb/0x480 drivers/bluetooth/hci_vhci.c:617
call_write_iter include/linux/fs.h:2110 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xa86/0xcb0 fs/read_write.c:590
ksys_write+0x1a0/0x2c0 fs/read_write.c:643
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5095 tgid 5095 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1141 [inline]
free_unref_page_prepare+0x986/0xab0 mm/page_alloc.c:2347
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
__folio_put_large+0x13f/0x190 mm/swap.c:132
__folio_put+0x299/0x390 mm/swap.c:140
folio_put include/linux/mm.h:1506 [inline]
free_large_kmalloc+0x105/0x1c0 mm/slub.c:4361
kfree+0x1ca/0x3a0 mm/slub.c:4384
hci_release_dev+0x1516/0x16a0 net/bluetooth/hci_core.c:2833
bt_host_release+0x83/0x90 net/bluetooth/hci_sysfs.c:94
device_release+0x9b/0x1c0
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x231/0x480 lib/kobject.c:737
vhci_release+0x8b/0xd0 drivers/bluetooth/hci_vhci.c:675
__fput+0x42b/0x8a0 fs/file_table.c:422
task_work_run+0x251/0x310 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa1b/0x27e0 kernel/exit.c:878
do_group_exit+0x207/0x2c0 kernel/exit.c:1027
__do_sys_exit_group kernel/exit.c:1038 [inline]
__se_sys_exit_group kernel/exit.c:1036 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036

Memory state around the buggy address:
ffff88807bee9480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88807bee9500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88807bee9580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88807bee9600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88807bee9680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

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If you want to undo deduplication, reply with:
#syz undup

[Hillf Danton]

On Mon, 22 Apr 2024 08:35:25 -0700

> syzbot found the following issue on:
>
> HEAD commit: 3cdb45594619 Merge tag 's390-6.9-4' of git://git.kernel.or..
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=144067cb180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 3cdb45594619

--- x/net/bluetooth/bnep/core.c
+++ y/net/bluetooth/bnep/core.c
@@ -659,7 +659,7 @@ int bnep_del_connection(struct bnep_conn
if (req->flags & ~valid_flags)
return -EINVAL;

- down_read(&bnep_session_sem);
+ down_write(&bnep_session_sem);

s = __bnep_get_session(req->dst);
if (s) {
@@ -668,7 +668,7 @@ int bnep_del_connection(struct bnep_conn
} else
err = -ENOENT;

- up_read(&bnep_session_sem);
+ up_write(&bnep_session_sem);
return err;
}

--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in netdev_unregister_kobject

==================================================================
BUG: KASAN: use-after-free in device_for_each_child+0xa7/0x170 drivers/base/core.c:4044

Read of size 8 at addr ffff8880293555f8 by task kbnepd bnep0/5664

CPU: 0 PID: 5664 Comm: kbnepd bnep0 Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
device_for_each_child+0xa7/0x170 drivers/base/core.c:4044
pm_runtime_set_memalloc_noio+0x114/0x260 drivers/base/power/runtime.c:248
netdev_unregister_kobject+0x178/0x250 net/core/net-sysfs.c:2106
unregister_netdevice_many_notify+0x11dd/0x16e0 net/core/dev.c:11135
unregister_netdevice_many net/core/dev.c:11163 [inline]
unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11042
unregister_netdevice include/linux/netdevice.h:3115 [inline]
unregister_netdev+0x1c/0x30 net/core/dev.c:11181
bnep_session+0x2e09/0x3000 net/bluetooth/bnep/core.c:525
kthread+0x2f2/0x390 kernel/kthread.c:388
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

The buggy address belongs to the physical page:

page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29355

flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()

raw: 00fff80000000000 ffffea0000a4d588 ffffea0000a4d508 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as freed

page last allocated via order 2, migratetype Unmovable, gfp_mask 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO), pid 5470, tgid 1627921193 (syz-executor.4), ts 5470, free_ts 128431373442

page last free pid 5470 tgid 5470 stack trace:

ffff888029355480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888029355500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888029355580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff888029355600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888029355680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


Tested on:

commit: 3cdb4559 Merge tag 's390-6.9-4' of git://git.kernel.or..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10c3d0d3180000

kernel config: https://syzkaller.appspot.com/x/.config?x=d239903bd07761e5
dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=105d6b20980000

[Hillf Danton]

On Mon, 22 Apr 2024 08:35:25 -0700

> syzbot found the following issue on:
>
> HEAD commit: 3cdb45594619 Merge tag 's390-6.9-4' of git://git.kernel.or..
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=144067cb180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 3cdb45594619

--- x/net/bluetooth/bnep/core.c
+++ y/net/bluetooth/bnep/core.c

@@ -535,6 +535,7 @@ static int bnep_session(void *arg)
__bnep_unlink_session(s);

up_write(&bnep_session_sem);
+ put_device(dev->dev.parent);
free_netdev(dev);
module_put_and_kthread_exit(0);
return 0;
@@ -618,7 +619,7 @@ int bnep_add_connection(struct bnep_conn
bnep_set_default_proto_filter(s);
#endif

- SET_NETDEV_DEV(dev, bnep_get_device(s));
+ SET_NETDEV_DEV(dev, get_device(bnep_get_device(s)));
SET_NETDEV_DEVTYPE(dev, &bnep_type);

err = register_netdev(dev);
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

KASAN: out-of-bounds Read in netdev_unregister_kobject

==================================================================
BUG: KASAN: out-of-bounds in device_for_each_child+0xa7/0x170 drivers/base/core.c:4044
Read of size 8 at addr ffff88806e92d5f8 by task kbnepd bnep0/5637

CPU: 0 PID: 5637 Comm: kbnepd bnep0 Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
device_for_each_child+0xa7/0x170 drivers/base/core.c:4044
pm_runtime_set_memalloc_noio+0x114/0x260 drivers/base/power/runtime.c:248
netdev_unregister_kobject+0x178/0x250 net/core/net-sysfs.c:2106
unregister_netdevice_many_notify+0x11dd/0x16e0 net/core/dev.c:11135
unregister_netdevice_many net/core/dev.c:11163 [inline]
unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11042
unregister_netdevice include/linux/netdevice.h:3115 [inline]
unregister_netdev+0x1c/0x30 net/core/dev.c:11181

bnep_session+0x2e09/0x3030 net/bluetooth/bnep/core.c:525

kthread+0x2f2/0x390 kernel/kthread.c:388
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

The buggy address belongs to the physical page:

page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6e92c
head: order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff80000000040(head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000040 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
head: 00fff80000000040 0000000000000000 dead000000000122 0000000000000000
head: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
head: 00fff80000000002 ffffea0001ba4b01 dead000000000122 00000000ffffffff
head: 0000000400000000 0000000000000000 00000000ffffffff 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 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO), pid 5732, tgid -1102947349 (syz-executor.3), ts 5732, free_ts 127654865274

page last free pid 5462 tgid 5462 stack trace:

ffff88806e92d500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806e92d580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88806e92d600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffff88806e92d680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806e92d700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

==================================================================


Tested on:

commit: 3cdb4559 Merge tag 's390-6.9-4' of git://git.kernel.or..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

console output: https://syzkaller.appspot.com/x/log.txt?x=12f4cd9f180000

kernel config: https://syzkaller.appspot.com/x/.config?x=d239903bd07761e5
dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=124cca53180000

[Hillf Danton]

On Mon, 22 Apr 2024 08:35:25 -0700

> syzbot found the following issue on:
>
> HEAD commit: 3cdb45594619 Merge tag 's390-6.9-4' of git://git.kernel.or..
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=144067cb180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 3cdb45594619

--- x/net/bluetooth/bnep/core.c
+++ y/net/bluetooth/bnep/core.c

@@ -540,16 +540,6 @@ static int bnep_session(void *arg)
return 0;
}

-static struct device *bnep_get_device(struct bnep_session *session)
-{
- struct l2cap_conn *conn = l2cap_pi(session->sock->sk)->chan->conn;
-
- if (!conn || !conn->hcon)
- return NULL;
-
- return &conn->hcon->dev;
-}
-
static const struct device_type bnep_type = {
.name = "bluetooth",
};
@@ -618,7 +608,6 @@ int bnep_add_connection(struct bnep_conn

bnep_set_default_proto_filter(s);
#endif

- SET_NETDEV_DEV(dev, bnep_get_device(s));

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+6cf565...@syzkaller.appspotmail.com

Tested on:

commit: 3cdb4559 Merge tag 's390-6.9-4' of git://git.kernel.or..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

console output: https://syzkaller.appspot.com/x/log.txt?x=119e4230980000

kernel config: https://syzkaller.appspot.com/x/.config?x=d239903bd07761e5
dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=15e9a8d3180000

Note: testing is done by a robot and is best-effort only.

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: KASAN: use-after-free Read in netdev_unregister_kobject
Author: dman...@yandex.ru

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next fb4560832d4c91d73680538d6659ac2c024ec9d5

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 629c302f7407..aaa7849c74f4 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2716,7 +2716,6 @@ void hci_unregister_dev(struct hci_dev *hdev)
rfkill_destroy(hdev->rfkill);
}

- device_del(&hdev->dev);
/* Actual cleanup is deferred until hci_release_dev(). */
hci_dev_put(hdev);
}
@@ -2756,6 +2755,8 @@ void hci_release_dev(struct hci_dev *hdev)
kfree_skb(hdev->sent_cmd);
kfree_skb(hdev->req_skb);
kfree_skb(hdev->recv_event);
+
+ device_del(&hdev->dev);
kfree(hdev);
}
EXPORT_SYMBOL(hci_release_dev);

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: KASAN: use-after-free Read in netdev_unregister_kobject
Author: dman...@yandex.ru

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git c2ee9f594da826bea183ed14f2cc029c719bf4da

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file net/bluetooth/hci_core.c
patch: **** unexpected end of file in patch



Tested on:

commit: fb456083 Bluetooth: ISO: Fix UAF on iso_sock_timeout
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next

kernel config: https://syzkaller.appspot.com/x/.config?x=d239903bd07761e5
dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler:

patch: https://syzkaller.appspot.com/x/patch.diff?x=12c4f640580000

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file net/bluetooth/hci_core.c
patch: **** unexpected end of file in patch



Tested on:

commit: c2ee9f59 KVM: selftests: Fix build on on non-x86 archi..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

kernel config: https://syzkaller.appspot.com/x/.config?x=d239903bd07761e5
dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler:

patch: https://syzkaller.appspot.com/x/patch.diff?x=1203665f980000

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: KASAN: use-after-free Read in netdev_unregister_kobject
Author: dman...@yandex.ru

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 6c52d4da1c742cd01a797a4d0a2d3c5a60dc9bfe

diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 367e32fe30eb..80ac537fa500 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -73,6 +73,8 @@ void hci_conn_del_sysfs(struct hci_conn *conn)
return;
}

+ device_move(&conn->dev, NULL, DPM_ORDER_DEV_LAST);
+
while (1) {
struct device *dev;

--
2.47.0

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: KASAN: use-after-free Read in netdev_unregister_kobject
Author: dman...@yandex.ru

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next dff8a64238a3f951dbf0930bac915eec7cae8200

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+6cf565...@syzkaller.appspotmail.com
Tested-by: syzbot+6cf565...@syzkaller.appspotmail.com

Tested on:

commit: 6c52d4da Merge tag 'for-linus' of git://git.kernel.org..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=121e5340580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2cf68159adbdf217
dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f

compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=107fe6f7980000

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+6cf565...@syzkaller.appspotmail.com
Tested-by: syzbot+6cf565...@syzkaller.appspotmail.com

Tested on:

commit: dff8a642 Bluetooth: btrtl: Decrease HCI_OP_RESET timeo..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next
console output: https://syzkaller.appspot.com/x/log.txt?x=144816f7980000
kernel config: https://syzkaller.appspot.com/x/.config?x=36917d9184c65129

dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=161c955f980000

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: [PATCH v2] Bluetooth: fix use-after-free in device_for_each_child()
Author: luiz....@gmail.com

#syz test

On Fri, Nov 1, 2024 at 7:44 AM Dmitry Antipov <dman...@yandex.ru> wrote:
>
> Syzbot has reported the following KASAN splat:
>
> BUG: KASAN: slab-use-after-free in device_for_each_child+0x18f/0x1a0
> Read of size 8 at addr ffff88801f605308 by task kbnepd bnep0/4980
>
> CPU: 0 UID: 0 PID: 4980 Comm: kbnepd bnep0 Not tainted 6.12.0-rc4-00161-gae90f6a6170d #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
> Call Trace:
> <TASK>
> dump_stack_lvl+0x100/0x190
> ? device_for_each_child+0x18f/0x1a0
> print_report+0x13a/0x4cb
> ? __virt_addr_valid+0x5e/0x590
> ? __phys_addr+0xc6/0x150
> ? device_for_each_child+0x18f/0x1a0
> kasan_report+0xda/0x110
> ? device_for_each_child+0x18f/0x1a0
> ? __pfx_dev_memalloc_noio+0x10/0x10
> device_for_each_child+0x18f/0x1a0
> ? __pfx_device_for_each_child+0x10/0x10
> pm_runtime_set_memalloc_noio+0xf2/0x180
> netdev_unregister_kobject+0x1ed/0x270
> unregister_netdevice_many_notify+0x123c/0x1d80
> ? __mutex_trylock_common+0xde/0x250
> ? __pfx_unregister_netdevice_many_notify+0x10/0x10
> ? trace_contention_end+0xe6/0x140
> ? __mutex_lock+0x4e7/0x8f0
> ? __pfx_lock_acquire.part.0+0x10/0x10
> ? rcu_is_watching+0x12/0xc0
> ? unregister_netdev+0x12/0x30
> unregister_netdevice_queue+0x30d/0x3f0
> ? __pfx_unregister_netdevice_queue+0x10/0x10
> ? __pfx_down_write+0x10/0x10
> unregister_netdev+0x1c/0x30
> bnep_session+0x1fb3/0x2ab0
> ? __pfx_bnep_session+0x10/0x10
> ? __pfx_lock_release+0x10/0x10
> ? __pfx_woken_wake_function+0x10/0x10
> ? __kthread_parkme+0x132/0x200
> ? __pfx_bnep_session+0x10/0x10
> ? kthread+0x13a/0x370
> ? __pfx_bnep_session+0x10/0x10
> kthread+0x2b7/0x370
> ? __pfx_kthread+0x10/0x10
> ret_from_fork+0x48/0x80
> ? __pfx_kthread+0x10/0x10
> ret_from_fork_asm+0x1a/0x30
> </TASK>
>
> Allocated by task 4974:
> kasan_save_stack+0x30/0x50
> kasan_save_track+0x14/0x30
> __kasan_kmalloc+0xaa/0xb0
> __kmalloc_noprof+0x1d1/0x440
> hci_alloc_dev_priv+0x1d/0x2820
> __vhci_create_device+0xef/0x7d0
> vhci_write+0x2c7/0x480
> vfs_write+0x6a0/0xfc0
> ksys_write+0x12f/0x260
> do_syscall_64+0xc7/0x250
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Freed by task 4979:
> kasan_save_stack+0x30/0x50
> kasan_save_track+0x14/0x30
> kasan_save_free_info+0x3b/0x60
> __kasan_slab_free+0x4f/0x70
> kfree+0x141/0x490
> hci_release_dev+0x4d9/0x600
> bt_host_release+0x6a/0xb0
> device_release+0xa4/0x240
> kobject_put+0x1ec/0x5a0
> put_device+0x1f/0x30
> vhci_release+0x81/0xf0
> __fput+0x3f6/0xb30
> task_work_run+0x151/0x250
> do_exit+0xa79/0x2c30
> do_group_exit+0xd5/0x2a0
> get_signal+0x1fcd/0x2210
> arch_do_signal_or_restart+0x93/0x780
> syscall_exit_to_user_mode+0x140/0x290
> do_syscall_64+0xd4/0x250
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> In 'hci_conn_del_sysfs()', 'device_unregister()' may be called when
> an underlying (kobject) reference counter is greater than 1. This
> means that reparenting (happened when the device is actually freed)
> is delayed and, during that delay, parent controller device (hciX)
> may be deleted. Since the latter may create a dangling pointer to
> freed parent, avoid that scenario by reparenting to NULL explicitly.
>
> Reported-by: syzbot+6cf565...@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
> Fixes: a85fb91e3d72 ("Bluetooth: Fix double free in hci_conn_cleanup")
> Signed-off-by: Dmitry Antipov <dman...@yandex.ru>
> ---
> v2: reparent per-connection 'struct device' explicitly
> ---
> net/bluetooth/hci_sysfs.c | 2 ++
> 1 file changed, 2 insertions(+)

>
> diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
> index 367e32fe30eb..80ac537fa500 100644
> --- a/net/bluetooth/hci_sysfs.c
> +++ b/net/bluetooth/hci_sysfs.c
> @@ -73,6 +73,8 @@ void hci_conn_del_sysfs(struct hci_conn *conn)
> return;
> }
>
> + device_move(&conn->dev, NULL, DPM_ORDER_DEV_LAST);
> +
> while (1) {
> struct device *dev;
>
> --
> 2.47.0
>

--
Luiz Augusto von Dentz

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

KASAN: slab-use-after-free Read in netdev_unregister_kobject

==================================================================
BUG: KASAN: slab-use-after-free in device_for_each_child+0xbb/0x1b0 drivers/base/core.c:3999
Read of size 8 at addr ffff888021c81308 by task kbnepd bnep0/5597

CPU: 0 UID: 0 PID: 5597 Comm: kbnepd bnep0 Not tainted 6.12.0-rc5-syzkaller-00181-g6c52d4da1c74 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120

print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601

device_for_each_child+0xbb/0x1b0 drivers/base/core.c:3999
pm_runtime_set_memalloc_noio+0x114/0x260 drivers/base/power/runtime.c:248
netdev_unregister_kobject+0x178/0x250 net/core/net-sysfs.c:2109
unregister_netdevice_many_notify+0x1851/0x1da0 net/core/dev.c:11441
unregister_netdevice_many net/core/dev.c:11469 [inline]
unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11343
unregister_netdevice include/linux/netdevice.h:3118 [inline]
unregister_netdev+0x1c/0x30 net/core/dev.c:11487
bnep_session+0x2e0e/0x3000 net/bluetooth/bnep/core.c:525
kthread+0x2f2/0x390 kernel/kthread.c:389

ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Allocated by task 5425:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:257 [inline]
__do_kmalloc_node mm/slub.c:4264 [inline]
__kmalloc_noprof+0x1fc/0x400 mm/slub.c:4276
kmalloc_noprof include/linux/slab.h:882 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
hci_alloc_dev_priv+0x27/0x2030 net/bluetooth/hci_core.c:2440
hci_alloc_dev include/net/bluetooth/hci_core.h:1621 [inline]
__vhci_create_device drivers/bluetooth/hci_vhci.c:399 [inline]
vhci_create_device+0x116/0x6a0 drivers/bluetooth/hci_vhci.c:470
vhci_get_user drivers/bluetooth/hci_vhci.c:527 [inline]
vhci_write+0x3cf/0x490 drivers/bluetooth/hci_vhci.c:607
new_sync_write fs/read_write.c:590 [inline]
vfs_write+0xaed/0xd30 fs/read_write.c:683
ksys_write+0x183/0x2b0 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5425:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 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+0x1a0/0x440 mm/slub.c:4727
hci_release_dev+0x1525/0x16b0 net/bluetooth/hci_core.c:2759

bt_host_release+0x83/0x90 net/bluetooth/hci_sysfs.c:94
device_release+0x9b/0x1c0
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x231/0x480 lib/kobject.c:737

vhci_release+0x88/0xd0 drivers/bluetooth/hci_vhci.c:665
__fput+0x241/0x880 fs/file_table.c:431
task_work_run+0x251/0x310 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa2f/0x28e0 kernel/exit.c:939
do_group_exit+0x207/0x2c0 kernel/exit.c:1088
__do_sys_exit_group kernel/exit.c:1099 [inline]
__se_sys_exit_group kernel/exit.c:1097 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097
x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
insert_work+0x3e/0x330 kernel/workqueue.c:2183
__queue_work+0xb66/0xf50 kernel/workqueue.c:2343
queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f2/0x390 kernel/kthread.c:389

ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Second to last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
insert_work+0x3e/0x330 kernel/workqueue.c:2183
__queue_work+0xc8b/0xf50 kernel/workqueue.c:2339
call_timer_fn+0x190/0x650 kernel/time/timer.c:1794
expire_timers kernel/time/timer.c:1840 [inline]
__run_timers kernel/time/timer.c:2419 [inline]
__run_timer_base+0x695/0x8e0 kernel/time/timer.c:2430
run_timer_base kernel/time/timer.c:2439 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449
handle_softirqs+0x2c7/0x980 kernel/softirq.c:554
__do_softirq kernel/softirq.c:588 [inline]
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

The buggy address belongs to the object at ffff888021c80000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 4872 bytes inside of
freed 8192-byte region [ffff888021c80000, ffff888021c82000)

The buggy address belongs to the physical page:

page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21c80
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff888015442280 0000000000000000 0000000000000001
raw: 0000000000000000 0000000000020002 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff888015442280 0000000000000000 0000000000000001
head: 0000000000000000 0000000000020002 00000001f5000000 0000000000000000
head: 00fff00000000003 ffffea0000872001 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 4752, tgid 4752 (S40network), ts 32094841667, free_ts 32026397912
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537
prep_new_page mm/page_alloc.c:1545 [inline]
get_page_from_freelist+0x303f/0x3190 mm/page_alloc.c:3457
__alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4733
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
alloc_slab_page+0x6a/0x120 mm/slub.c:2412
allocate_slab+0x5a/0x2f0 mm/slub.c:2578
new_slab mm/slub.c:2631 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3818
__slab_alloc+0x58/0xa0 mm/slub.c:3908
__slab_alloc_node mm/slub.c:3961 [inline]
slab_alloc_node mm/slub.c:4122 [inline]
__kmalloc_cache_noprof+0x1d5/0x2c0 mm/slub.c:4290
kmalloc_noprof include/linux/slab.h:878 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
tomoyo_print_bprm security/tomoyo/audit.c:26 [inline]
tomoyo_init_log+0x11cd/0x2050 security/tomoyo/audit.c:264
tomoyo_supervisor+0x38a/0x11f0 security/tomoyo/common.c:2089
tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
tomoyo_env_perm+0x178/0x210 security/tomoyo/environ.c:63
tomoyo_environ security/tomoyo/domain.c:672 [inline]
tomoyo_find_next_domain+0x146e/0x1d40 security/tomoyo/domain.c:881
tomoyo_bprm_check_security+0x114/0x180 security/tomoyo/tomoyo.c:102
security_bprm_check+0x86/0x250 security/security.c:1297
search_binary_handler fs/exec.c:1740 [inline]
exec_binprm fs/exec.c:1794 [inline]
bprm_execve+0xa56/0x1770 fs/exec.c:1845
page last free pid 4751 tgid 4751 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1108 [inline]
free_unref_page+0xcfb/0xf20 mm/page_alloc.c:2638
__slab_free+0x31b/0x3d0 mm/slub.c:4490
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:247 [inline]
slab_post_alloc_hook mm/slub.c:4085 [inline]
slab_alloc_node mm/slub.c:4134 [inline]
kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4141
vm_area_alloc+0x24/0x1d0 kernel/fork.c:472
mmap_region+0x1134/0x2940 mm/mmap.c:1436
do_mmap+0x8f0/0x1000 mm/mmap.c:496
vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:588
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:

ffff888021c81200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888021c81280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888021c81300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888021c81380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888021c81400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Tested on:

commit: 6c52d4da Merge tag 'for-linus' of git://git.kernel.org..

git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15e81630580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2cf68159adbdf217

dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: [PATCH v2] Bluetooth: fix use-after-free in device_for_each_child()
Author: luiz....@gmail.com

On Fri, Nov 1, 2024 at 1:37 PM Luiz Augusto von Dentz
<luiz....@gmail.com> wrote:
>
> Hi Dmitry,
>
> On Fri, Nov 1, 2024 at 11:31 AM Luiz Augusto von Dentz
> <luiz....@gmail.com> wrote:
> >
> > Hi Dmitry,
> >
> > On Fri, Nov 1, 2024 at 11:17 AM Dmitry Antipov <dman...@yandex.ru> wrote:
> > >
> > > On 11/1/24 6:12 PM, Luiz Augusto von Dentz wrote:
> > >
> > > > There is no Tested-by thus why I assumed it wasn't tested by syzbot yet.
> > >
> > > Ugh. Until today I've assumed that Tested-by: is applicable to human-driven
> > > testing only :-).
> >
> > Nope, in fact it is very handy to have syzbot test your changes since
> > it may hit other problems as well.
>
> Looks like this doesn't solve the problem, in fact I think you are
> getting it backwards, you are trying to reparent the parent dev not
> the child and I assume by destroying the parent device there should be
> some way to reset the parent which seems to be the intent the
> following code in hci_conn_del_sysfs:

>
> while (1) {
> struct device *dev;
>

> dev = device_find_child(&conn->dev, NULL, __match_tty);
> if (!dev)
> break;
> device_move(dev, NULL, DPM_ORDER_DEV_LAST);
> put_device(dev);
> }
>
> But note that it only does that after matching tty, but I guess we
> want to do it regardless otherwise we may have the child objects still
> access it, that said we should probably use device_for_each_child
> though if that is safe to do calls to device_move under its callback.

#syz test

> > > Dmitry

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+6cf565...@syzkaller.appspotmail.com
Tested-by: syzbot+6cf565...@syzkaller.appspotmail.com

Tested on:

commit: c4264568 Merge tag 'acpi-6.12-rc6' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148ad340580000

kernel config: https://syzkaller.appspot.com/x/.config?x=2cf68159adbdf217
dashboard link: https://syzkaller.appspot.com/bug?extid=6cf5652d3df49fae2e3f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=1122d340580000