[syzbot] [bpf?] WARNING in tcx_uninstall

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6bfef2ec0172 Merge branch 'net-page_pool-remove-page_pool_..
git tree: net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=131ca4e6a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8acaeb93ad7c6aaa
dashboard link: https://syzkaller.appspot.com/bug?extid=376a289e86a0fd02b9ba
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14aabbaaa80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17c5cbaaa80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4a9243441696/disk-6bfef2ec.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aae660d02e45/vmlinux-6bfef2ec.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8aaadbed7a6a/bzImage-6bfef2ec.xz

The issue was bisected to:

commit e420bed025071a623d2720a92bc2245c84757ecb
Author: Daniel Borkmann <dan...@iogearbox.net>
Date: Wed Jul 19 14:08:52 2023 +0000

bpf: Add fd-based tcx multi-prog infra with link support

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=11496cbea80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=13496cbea80000
console output: https://syzkaller.appspot.com/x/log.txt?x=15496cbea80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+376a28...@syzkaller.appspotmail.com
Fixes: e420bed02507 ("bpf: Add fd-based tcx multi-prog infra with link support")

------------[ cut here ]------------
WARNING: CPU: 1 PID: 5181 at kernel/bpf/tcx.c:114 tcx_uninstall+0x542/0x630 kernel/bpf/tcx.c:114
Modules linked in:
CPU: 1 PID: 5181 Comm: syz-executor399 Not tainted 6.5.0-rc2-syzkaller-00549-g6bfef2ec0172 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
RIP: 0010:tcx_uninstall+0x542/0x630 kernel/bpf/tcx.c:114
Code: 4c 00 00 00 48 c7 c6 a0 0f 76 8a 48 c7 c7 e0 0f 76 8a c6 05 b7 f2 ec 0c 01 e8 ba 6b a4 ff 0f 0b e9 fc fa ff ff e8 fe a1 dd ff <0f> 0b e9 92 fd ff ff e8 f2 a1 dd ff 44 0f b6 25 93 f2 ec 0c 31 ff
RSP: 0018:ffffc9000409f108 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff88801f663b80 RSI: ffffffff81a8dc32 RDI: 0000000000000001
RBP: ffff888023e16008 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: ffff888023e16008 R14: 0000000000000000 R15: 0000000000000001
FS: 00007f50a1a326c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f42a5984018 CR3: 000000002d318000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
dev_tcx_uninstall include/net/tcx.h:174 [inline]
unregister_netdevice_many_notify+0x5e7/0x1a20 net/core/dev.c:10899
rtnl_delete_link net/core/rtnetlink.c:3213 [inline]
rtnl_dellink+0x3c1/0xae0 net/core/rtnetlink.c:3265
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6423
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2546
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1911
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f50a1a96349
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 1a 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f50a1a32218 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f50a1b1f438 RCX: 00007f50a1a96349
RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000005
RBP: 00007f50a1b1f430 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f50a1b1f43c
R13: 00007f50a1aec4f4 R14: 0031313230386c6e R15: 746361736c630001
</TASK>


---
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.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

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

[syzbot]

> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/martin.lau/bpf-next.git e010522b3158

Your commands are accepted, but please keep syzkall...@googlegroups.com mailing list in CC next time. It serves as a history of what happened with each bug report. Thank you.

>

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+376a28...@syzkaller.appspotmail.com

Tested on:

commit: e010522b tcx: Fix splat during dev unregister
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/martin.lau/bpf-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1451adbea80000

kernel config: https://syzkaller.appspot.com/x/.config?x=8acaeb93ad7c6aaa
dashboard link: https://syzkaller.appspot.com/bug?extid=376a289e86a0fd02b9ba
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

[syzbot]

> On 7/28/23 3:54 AM, Martin KaFai Lau wrote:
>> On 7/25/23 7:51 PM, syzbot wrote:
>>> Hello,
>>>
>>> syzbot found the following issue on:
>>>
>>> HEAD commit:    6bfef2ec0172 Merge branch 'net-page_pool-remove-page_pool_..
>>> git tree:       net-next
>>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=131ca4e6a80000

>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=8acaeb93ad7c6aaa
>>> dashboard link: https://syzkaller.appspot.com/bug?extid=376a289e86a0fd02b9ba
>>> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

>>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14aabbaaa80000
>>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17c5cbaaa80000
>>>
>>> Downloadable assets:
>>> disk image: https://storage.googleapis.com/syzbot-assets/4a9243441696/disk-6bfef2ec.raw.xz
>>> vmlinux: https://storage.googleapis.com/syzbot-assets/aae660d02e45/vmlinux-6bfef2ec.xz
>>> kernel image: https://storage.googleapis.com/syzbot-assets/8aaadbed7a6a/bzImage-6bfef2ec.xz
>

> #syz test: https://github.com/cilium/linux.git pr/new-api-tcx8

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+376a28...@syzkaller.appspotmail.com

Tested on:

commit: 9879d7c4 bpf, vmtest: Build test_progs as statically l..
git tree: https://github.com/cilium/linux.git pr/new-api-tcx8
console output: https://syzkaller.appspot.com/x/log.txt?x=15e400dea80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e496290b18473ac7

dashboard link: https://syzkaller.appspot.com/bug?extid=376a289e86a0fd02b9ba
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40