Patch "modpost: fix removing numeric suffixes" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    modpost: fix removing numeric suffixes

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     modpost-fix-removing-numeric-suffixes.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3abf029fa63349fed5d1e5b62ecaa3bdf3203c80
Author: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
Date:   Tue May 24 17:27:18 2022 +0200

    modpost: fix removing numeric suffixes
    
    [ Upstream commit b5beffa20d83c4e15306c991ffd00de0d8628338 ]
    
    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@xxxxxxxxx>
    Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
    Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index e08f75aed429..a21aa74b4948 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1982,7 +1982,7 @@ 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;