=====================================================
BUG: KMSAN: uninit-value in check_pointer lib/vsprintf.c:705 [inline]
BUG: KMSAN: uninit-value in string+0x3d2/0x700 lib/vsprintf.c:717
 check_pointer lib/vsprintf.c:705 [inline]
 string+0x3d2/0x700 lib/vsprintf.c:717
 vsnprintf+0x224f/0x36a0 lib/vsprintf.c:2805
 sprintf+0x20e/0x260 lib/vsprintf.c:3007
 batadv_mcast_flags_log net/batman-adv/multicast.c:811 [inline]
 batadv_mcast_mla_flags_update net/batman-adv/multicast.c:846 [inline]
 __batadv_mcast_mla_update net/batman-adv/multicast.c:889 [inline]
 batadv_mcast_mla_update+0x4fcf/0x5830 net/batman-adv/multicast.c:915
 process_one_work+0xdc2/0x1820 kernel/workqueue.c:2298
 worker_thread+0x10f1/0x2290 kernel/workqueue.c:2445
 kthread+0x721/0x850 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

Local variable vfork created at:
 kernel_clone+0x7a/0x1170 kernel/fork.c:2546
 kernel_thread+0x17a/0x240 kernel/fork.c:2636

CPU: 1 PID: 39 Comm: kworker/u4:1 Tainted: G        W         5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_mcast_mla_update
=====================================================