Re: [syzbot] KASAN: use-after-free Read in netdev_core_pick_tx

[syzbot]

Hello,

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

device veth1_macvtap left promiscuous mode
device veth0_macvtap left promiscuous mode
device veth1_vlan left promiscuous mode
device veth0_vlan left promiscuous mode
bond6 (unregistering): Released all slaves
------------[ cut here ]------------
WARNING: CPU: 0 PID: 45 at net/core/dev.c:10770 unregister_netdevice_many+0x1421/0x1950
Modules linked in:
CPU: 1 PID: 45 Comm: kworker/u4:2 Not tainted 5.18.0-rc7-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: netns cleanup_net
RIP: 0010:unregister_netdevice_many+0x1421/0x1950 net/core/dev.c:10770
Code: 74 08 48 89 df e8 7f 68 ae f9 48 8b 1b 48 89 5c 24 40 4c 39 fb 0f 84 0c 01 00 00 e8 a9 80 5d f9 e9 64 f6 ff ff e8 9f 80 5d f9 <0f> 0b e9 2a ff ff ff e8 93 80 5d f9 0f 0b e9 7a ff ff ff e8 87 80
RSP: 0018:ffffc90000b678e0 EFLAGS: 00010293
RAX: ffffffff88289461 RBX: ffff888016ea00a0 RCX: ffff888017138000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000b67a50 R08: ffffffff88289345 R09: fffffbfff1b74a89
R10: fffffbfff1b74a89 R11: 1ffffffff1b74a88 R12: ffff888023fb8e80
R13: 0000000000000002 R14: dffffc0000000000 R15: ffffc90000b67ae0
FS:  0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc044717a70 CR3: 0000000074978000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 default_device_exit_batch+0x660/0x6d0 net/core/dev.c:11241
 ops_exit_list net/core/net_namespace.c:167 [inline]
 cleanup_net+0x80c/0xc50 net/core/net_namespace.c:594
 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
 kthread+0x266/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30
 </TASK>


Tested on:

commit:         42226c98 Linux 5.18-rc7
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16c9e702880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d84df8e1a4c4d5a4
dashboard link: https://syzkaller.appspot.com/bug?extid=10a7a8ca6e94600110ec
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
patch:          https://syzkaller.appspot.com/x/patch.diff?x=134b9a95880000