[syzbot] [wpan?] KMSAN: uninit-value in ieee802154_max_payload

[syzbot <syzbot+fe68c78fbbd3c0ad70ee@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    5b032cac6225 Merge tag 'ubifs-for-linus-6.16-rc1' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14d0820c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=529cf323140e1748
dashboard link: https://syzkaller.appspot.com/bug?extid=fe68c78fbbd3c0ad70ee
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2e197ad38b02/disk-5b032cac.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f05af0a6e9f6/vmlinux-5b032cac.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d7c0456f7931/bzImage-5b032cac.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe68c78fbbd3c0ad70ee@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in ieee802154_max_payload+0x399/0x3c0 net/ieee802154/header_ops.c:372
 ieee802154_max_payload+0x399/0x3c0 net/ieee802154/header_ops.c:372
 ieee802154_header_create+0x99b/0xb90 net/mac802154/iface.c:403
 wpan_dev_hard_header include/net/cfg802154.h:525 [inline]
 dgram_sendmsg+0xb3d/0x16d0 net/ieee802154/socket.c:677
 ieee802154_sock_sendmsg+0x92/0xd0 net/ieee802154/socket.c:96
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x330/0x3d0 net/socket.c:727
 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566
 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2655
 x64_sys_call+0x32fb/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable hdr created at:
 ieee802154_header_create+0x4e/0xb90 net/mac802154/iface.c:360
 wpan_dev_hard_header include/net/cfg802154.h:525 [inline]
 dgram_sendmsg+0xb3d/0x16d0 net/ieee802154/socket.c:677

CPU: 1 UID: 0 PID: 17215 Comm: syz.9.2647 Not tainted 6.15.0-syzkaller-13659-g5b032cac6225 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
=====================================================


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