From b5beffa20d83c4e15306c991ffd00de0d8628338 Mon Sep 17 00:00:00 2001
From: Alexander Lobakin <alexandr.lobakin@intel.com>
Date: Tue, 24 May 2022 17:27:18 +0200
Subject: [PATCH] modpost: fix removing numeric suffixes
Git-commit: b5beffa20d83c4e15306c991ffd00de0d8628338
Patch-mainline: v5.19-rc1
References: git-fixes

With the `-z unique-symbol` linker flag or any similar mechanism,
it is possible to trigger the following:

Error: modpost: "param_set_uint.0" [vmlinux] is a static EXPORT_SYMBOL

The reason is that for now the condition from remove_dot():

if (m && (s[n + m] == '.' || s[n + m] == 0))

which was designed to test if it's a dot or a '\0' after the suffix
is never satisfied.
This is due to that `s[n + m]` always points to the last digit of a
numeric suffix, not on the symbol next to it (from a custom debug
print added to modpost):

param_set_uint.0, s[n + m] is '0', s[n + m + 1] is '\0'

So it's off-by-one and was like that since 2014.

Fix this for the sake of any potential upcoming features, but don't
bother stable-backporting, as it's well hidden -- apart from that
LD flag, it can be triggered only with GCC LTO which never landed
upstream.

Fixes: fcd38ed0ff26 ("scripts: modpost: fix compilation warning")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 scripts/mod/modpost.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1997,7 +1997,7 @@ static char *remove_dot(char *s)
 
 	if (n && s[n]) {
 		size_t m = strspn(s + n + 1, "0123456789");
-		if (m && (s[n + m] == '.' || s[n + m] == 0))
+		if (m && (s[n + m + 1] == '.' || s[n + m + 1] == 0))
 			s[n] = 0;
 	}
 	return s;