init/initramfs: Fix argument forwarding to panic() in panic_show_mem()

Forwarding variadic argument lists can't be done by passing a va_list
to a function with signature foo(...) (as panic() has). It ends up
interpreting the va_list itself as a single argument instead of
iterating it. printf() happily accepts it of course, leading to corrupt
output.

Convert panic_show_mem() to a macro to allow forwarding the arguments.
The function is trivial enough that it's easier than trying to introduce
a vpanic() variant.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

init/initramfs.c

@@ -60,15 +60,8 @@ static void __init error(char *x)
 		message = x;
 }
 
-static void panic_show_mem(const char *fmt, ...)
-{
-	va_list args;
-
-	show_mem(0, NULL);
-	va_start(args, fmt);
-	panic(fmt, args);
-	va_end(args);
-}
+#define panic_show_mem(fmt, ...) \
+	({ show_mem(0, NULL); panic(fmt, ##__VA_ARGS__); })
 
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