[syzbot] [net?] WARNING in ip6_route_info_create

[syzbot <syzbot+c15aa445274af8674f41@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    5a08d0065a91 ipv6: add debug checks in fib6_info_release()
git tree:       net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=175698dae80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f8715b6ede5c4b90
dashboard link: https://syzkaller.appspot.com/bug?extid=c15aa445274af8674f41
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=16070374e80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=145e1574e80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/12a59d7df47f/disk-5a08d006.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/14f0ca0a861e/vmlinux-5a08d006.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ae9306decbe5/bzImage-5a08d006.xz

The issue was bisected to:

commit 5a08d0065a915ccf325563d7ca57fa8b4897881c
Author: Eric Dumazet <edumazet@google.com>
Date:   Tue Dec 5 17:32:50 2023 +0000

    ipv6: add debug checks in fib6_info_release()

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1137437ae80000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1337437ae80000
console output: https://syzkaller.appspot.com/x/log.txt?x=1537437ae80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c15aa445274af8674f41@syzkaller.appspotmail.com
Fixes: 5a08d0065a91 ("ipv6: add debug checks in fib6_info_release()")

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5062 at include/net/ip6_fib.h:332 fib6_info_release include/net/ip6_fib.h:332 [inline]
WARNING: CPU: 0 PID: 5062 at include/net/ip6_fib.h:332 ip6_route_info_create+0x1a1a/0x1f10 net/ipv6/route.c:3829
Modules linked in:
CPU: 0 PID: 5062 Comm: syz-executor399 Not tainted 6.7.0-rc3-syzkaller-00805-g5a08d0065a91 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:fib6_info_release include/net/ip6_fib.h:332 [inline]
RIP: 0010:ip6_route_info_create+0x1a1a/0x1f10 net/ipv6/route.c:3829
Code: 49 83 7f 40 00 75 28 e8 04 ae 50 f8 49 8d bf a0 00 00 00 48 c7 c6 c0 ae 37 89 e8 41 2c 3a f8 e9 65 f4 ff ff e8 e7 ad 50 f8 90 <0f> 0b 90 eb ad e8 dc ad 50 f8 90 0f 0b 90 eb cd e8 d1 ad 50 f8 e8
RSP: 0018:ffffc900039cf8e0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000400000 RCX: ffffffff8936e418
RDX: ffff888014695940 RSI: ffffffff8936e469 RDI: 0000000000000005
RBP: ffffc900039cf9d0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000400000 R11: ffffffff8aa0008b R12: ffffffffffffffed
R13: ffff88802560682c R14: ffffc900039cfac4 R15: ffff888025606800
FS:  00005555567bb380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000200001c2 CR3: 00000000793d5000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ip6_route_add+0x26/0x1f0 net/ipv6/route.c:3843
 ipv6_route_ioctl+0x3ff/0x590 net/ipv6/route.c:4467
 inet6_ioctl+0x265/0x2b0 net/ipv6/af_inet6.c:575
 sock_do_ioctl+0x113/0x270 net/socket.c:1220
 sock_ioctl+0x22e/0x6b0 net/socket.c:1339
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl fs/ioctl.c:857 [inline]
 __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f73fa33f369
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffce78f30b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffce78f3288 RCX: 00007f73fa33f369
RDX: 00000000200001c0 RSI: 000000000000890b RDI: 0000000000000003
RBP: 00007f73fa3b2610 R08: 0000000000000000 R09: 00007ffce78f3288
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffce78f3278 R14: 0000000000000001 R15: 0000000000000001
 </TASK>


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