UBSAN: use the kernel panic message markers

Use the same splat markers as panic does for easier matching by external
tools scanning kernel dmesg for splats.

Link: https://lkml.kernel.org/r/20231218135339.23209-1-bp@alien8.deSigned-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/ubsan.c

@@ -204,8 +204,8 @@ static void ubsan_prologue(struct source_location *loc, const char *reason)
 {
 	current->in_ubsan++;
 
-	pr_err("========================================"
-		"========================================\n");
+	pr_warn(CUT_HERE);
+
 	pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name,
 		loc->line & LINE_MASK, loc->column & COLUMN_MASK);
 
@@ -215,8 +215,7 @@ static void ubsan_prologue(struct source_location *loc, const char *reason)
 static void ubsan_epilogue(void)
 {
 	dump_stack();
-	pr_err("========================================"
-		"========================================\n");
+	pr_warn("---[ end trace ]---\n");
 
 	current->in_ubsan--;