FS:  00007fea988d8700(0000) GS:ffff88813fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000200002c0 CR3: 0000000115b99000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
=====================================================
BUG: KMSAN: uninit-value in show_trace_log_lvl+0x825/0xbb0 arch/x86/kernel/dumpstack.c:246
 show_trace_log_lvl+0x825/0xbb0 arch/x86/kernel/dumpstack.c:246
 show_regs+0xad/0xd0 arch/x86/kernel/dumpstack.c:469
 __warn+0x242/0x580 kernel/panic.c:596
 report_bug+0x7d4/0x9e0 lib/bug.c:199
 handle_bug+0x41/0x70 arch/x86/kernel/traps.c:315
 exc_invalid_op+0x1b/0x50 arch/x86/kernel/traps.c:335
 asm_exc_invalid_op+0x12/0x20
 netif_napi_add+0xa0e/0xed0
 netif_tx_napi_add include/linux/netdevice.h:2524 [inline]
 tun_napi_init drivers/net/tun.c:271 [inline]
 tun_attach+0xe26/0x21a0 drivers/net/tun.c:813
 tun_net_init+0x468/0x650 drivers/net/tun.c:994
 register_netdevice+0x4bf/0x21f0 net/core/dev.c:9891
 tun_set_iff+0xc14/0x1610 drivers/net/tun.c:2810
 __tun_chr_ioctl+0xcfb/0x3bd0 drivers/net/tun.c:3069
 tun_chr_ioctl+0x3f/0x50 drivers/net/tun.c:3354
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x222/0x400 fs/ioctl.c:856
 __x64_sys_ioctl+0x92/0xd0 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Local variable tmp created at:
 number+0x75/0x1ff0 lib/vsprintf.c:458
 vsnprintf+0x1d0a/0x29a0 lib/vsprintf.c:2872

CPU: 0 PID: 3475 Comm: syz-executor333 Not tainted 5.18.0-syzkaller-16265-g365ac3bfacfb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================