=====================================================
BUG: KMSAN: uninit-value in check_pointer lib/vsprintf.c:705 [inline]
BUG: KMSAN: uninit-value in string+0x3cf/0x6f0 lib/vsprintf.c:717
 check_pointer lib/vsprintf.c:705 [inline]
 string+0x3cf/0x6f0 lib/vsprintf.c:717
 vsnprintf+0x2222/0x3650 lib/vsprintf.c:2805
 seq_vprintf fs/seq_file.c:391 [inline]
 seq_printf+0x314/0x4f0 fs/seq_file.c:406
 kcm_format_mux_header net/kcm/kcmproc.c:92 [inline]
 kcm_seq_show+0xe98/0x1c80 net/kcm/kcmproc.c:227
 seq_read_iter+0xaac/0x2150 fs/seq_file.c:230
 seq_read+0x7a6/0x990 fs/seq_file.c:162
 pde_read fs/proc/inode.c:311 [inline]
 proc_reg_read+0x39d/0x560 fs/proc/inode.c:323
 do_iter_read+0xeb9/0x14c0 fs/read_write.c:788
 vfs_readv fs/read_write.c:906 [inline]
 do_preadv+0x45e/0x6c0 fs/read_write.c:998
 __do_compat_sys_preadv fs/read_write.c:1104 [inline]
 __se_compat_sys_preadv fs/read_write.c:1098 [inline]
 __ia32_compat_sys_preadv+0x166/0x1c0 fs/read_write.c:1098
 do_syscall_32_irqs_on arch/x86/entry/common.c:114 [inline]
 __do_fast_syscall_32+0x96/0xf0 arch/x86/entry/common.c:180
 do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Local variable sample.i created at:
 perf_log_itrace_start kernel/events/core.c:9069 [inline]
 event_sched_in+0x132b/0x35c0 kernel/events/core.c:2557
 group_sched_in kernel/events/core.c:2595 [inline]
 merge_sched_in kernel/events/core.c:3746 [inline]
 visit_groups_merge+0x2919/0x7460 kernel/events/core.c:3696

CPU: 0 PID: 19858 Comm: syz-executor.5 Tainted: G        W         5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================