[syzbot] [fs?] WARNING in netdev_queue_update_kobjects (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f99c5f563c17 Merge tag 'nf-24-03-21' of git://git.kernel.o..
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=152c0d20980000
kernel config: https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
dashboard link: https://syzkaller.appspot.com/bug?extid=41cf3f847df2c5f600a3
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=16d3d1fd180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=141dd66f180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/65d3f3eb786e/disk-f99c5f56.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/799cf7f28ff8/vmlinux-f99c5f56.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ab26c60c3845/bzImage-f99c5f56.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+41cf3f...@syzkaller.appspotmail.com

------------[ cut here ]------------
sysfs group 'byte_queue_limits' not found for kobject 'tx-0'
WARNING: CPU: 0 PID: 5073 at fs/sysfs/group.c:284 sysfs_remove_group+0x17f/0x2b0 fs/sysfs/group.c:282
Modules linked in:
CPU: 0 PID: 5073 Comm: kbnepd bnep0 Not tainted 6.8.0-syzkaller-05271-gf99c5f563c17 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:sysfs_remove_group+0x17f/0x2b0 fs/sysfs/group.c:282
Code: 36 4c 89 e0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 e7 e8 b5 f4 c2 ff 49 8b 14 24 48 c7 c7 c0 33 bb 8b 4c 89 f6 e8 b2 87 22 ff 90 <0f> 0b 90 90 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc
RSP: 0018:ffffc90003a3f8a0 EFLAGS: 00010246
RAX: 665251c6ceee3200 RBX: ffff888076fb7050 RCX: ffff88802254bc00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff8157cc12 R09: 1ffff92000747e68
R10: dffffc0000000000 R11: fffff52000747e69 R12: ffff888076fb7020
R13: 1ffffffff1941fac R14: ffffffff8ca10560 R15: ffff88802d2fc740
FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdbcd9e8a8 CR3: 000000002bf2a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
netdev_queue_update_kobjects+0x532/0x5f0 net/core/net-sysfs.c:1852
remove_queue_kobjects net/core/net-sysfs.c:1951 [inline]
netdev_unregister_kobject+0x110/0x250 net/core/net-sysfs.c:2104
unregister_netdevice_many_notify+0x11d4/0x16d0 net/core/dev.c:11129
unregister_netdevice_many net/core/dev.c:11157 [inline]
unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11036
unregister_netdevice include/linux/netdevice.h:3115 [inline]
unregister_netdev+0x1c/0x30 net/core/dev.c:11175
bnep_session+0x2e09/0x3000 net/bluetooth/bnep/core.c:525
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
</TASK>


---
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[Hillf Danton]

On Mon, 22 Apr 2024 08:46:25 -0700

> syzbot found the following issue on:
>
> HEAD commit: f99c5f563c17 Merge tag 'nf-24-03-21' of git://git.kernel.o..
> git tree: net

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=141dd66f180000

#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));
SET_NETDEV_DEVTYPE(dev, &bnep_type);

err = register_netdev(dev);
--

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+41cf3f...@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=14d33610980000
kernel config: https://syzkaller.appspot.com/x/.config?x=c6e826cf3c9c6ffc

dashboard link: https://syzkaller.appspot.com/bug?extid=41cf3f847df2c5f600a3
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=1609eb73180000

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