[syzbot] [batman?] WARNING in call_netdevice_notifiers_info

Hello,

syzbot found the following issue on:

HEAD commit: d44036cad311 net: dsa: felix: fix oversize frame dropping .. git tree: net console+strace: https://syzkaller.appspot.com/x/log.txt?x=10f7ce23a80000 kernel config: https://syzkaller.appspot.com/x/.config?x=aa796b6080b04102 dashboard link: https://syzkaller.appspot.com/bug?extid=f8812454d9b3ac00d282 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=125cb53ba80000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=131847f7a80000

Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/9936144a6193/disk-d44036ca.raw.... vmlinux: https://storage.googleapis.com/syzbot-assets/1278ad87465f/vmlinux-d44036ca.x... kernel image: https://storage.googleapis.com/syzbot-assets/b1a057709018/bzImage-d44036ca.x...

The issue was bisected to:

commit c6a953cce8d0438391e6da48c8d0793d3fbfcfa6 Author: Sven Eckelmann sven@narfation.org Date: Wed Jul 19 07:29:29 2023 +0000

batman-adv: Trigger events for auto adjusted MTU

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=104ef373a80000 final oops: https://syzkaller.appspot.com/x/report.txt?x=124ef373a80000 console output: https://syzkaller.appspot.com/x/log.txt?x=144ef373a80000

IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f8812454d9b3ac00d282@syzkaller.appspotmail.com Fixes: c6a953cce8d0 ("batman-adv: Trigger events for auto adjusted MTU")

------------[ cut here ]------------ RTNL: assertion failed at net/core/dev.c (1953) WARNING: CPU: 0 PID: 5033 at net/core/dev.c:1953 call_netdevice_notifiers_info+0x107/0x130 net/core/dev.c:1953 Modules linked in: CPU: 0 PID: 5033 Comm: syz-executor368 Not tainted 6.5.0-rc6-syzkaller-00126-gd44036cad311 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 RIP: 0010:call_netdevice_notifiers_info+0x107/0x130 net/core/dev.c:1953 Code: f9 40 84 ed 75 8d e8 d8 68 5e f9 ba a1 07 00 00 48 c7 c6 e0 34 81 8b 48 c7 c7 20 35 81 8b c6 05 07 35 6e 06 01 e8 f9 2a 25 f9 <0f> 0b e9 62 ff ff ff 48 89 df e8 ea 75 b2 f9 e9 15 ff ff ff e8 e0 RSP: 0018:ffffc900039df2b8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffffc900039df320 RCX: 0000000000000000 RDX: ffff88802d421dc0 RSI: ffffffff814ccc86 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000018 R13: ffff888078c30000 R14: ffff88807d45c0e8 R15: 0000000000000001 FS: 0000555555ccd380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000066a4e0 CR3: 000000007c0e3000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> call_netdevice_notifiers_extack net/core/dev.c:2000 [inline] call_netdevice_notifiers net/core/dev.c:2014 [inline] dev_set_mtu_ext+0x1e8/0x5d0 net/core/dev.c:8664 dev_set_mtu+0xb1/0x160 net/core/dev.c:8694 batadv_update_min_mtu+0x6e/0x90 net/batman-adv/hard-interface.c:645 batadv_netlink_set_mesh+0x7d8/0x14e0 net/batman-adv/netlink.c:498 genl_family_rcv_msg_doit.isra.0+0x1ef/0x2d0 net/netlink/genetlink.c:970 genl_family_rcv_msg net/netlink/genetlink.c:1050 [inline] genl_rcv_msg+0x559/0x800 net/netlink/genetlink.c:1067 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1078 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:1914 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: 0033:0x7ff089227659 Code: 48 83 c4 28 c3 e8 d7 19 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:00007ffdbc91ce88 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ff089274390 RCX: 00007ff089227659 RDX: 0000000000000000 RSI: 00000000200005c0 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000555500000000 R09: 0000555500000000 R10: 0000555500000000 R11: 0000000000000246 R12: 00007ffdbc91ced0 R13: 00007ffdbc91cea0 R14: 0000000000000001 R15: 00007ffdbc91ced0 </TASK>

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