Subject: [syzbot] [bpf?] WARNING in tcx_uninstall

From: syzbot <[email-masked]>
Date: Tue, 25 Jul 2023 19:51:02 -0700

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 <[email-masked]>
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: [email-masked]
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>

---
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