This is a note to let you know that I've just added the patch titled kconfig: fix infinite loop when expanding a macro at the end of file to the 6.1-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: kconfig-fix-infinite-loop-when-expanding-a-macro-at-.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 32fdb892778c62b9650ce52afa9a752fccd32ee7 Author: Masahiro Yamada <masahiroy@xxxxxxxxxx> Date: Sat Feb 3 00:57:59 2024 +0900 kconfig: fix infinite loop when expanding a macro at the end of file [ Upstream commit af8bbce92044dc58e4cc039ab94ee5d470a621f5 ] A macro placed at the end of a file with no newline causes an infinite loop. [Test Kconfig] $(info,hello) \ No newline at end of file I realized that flex-provided input() returns 0 instead of EOF when it reaches the end of a file. Fixes: 104daea149c4 ("kconfig: reference environment variables directly and remove 'option env='") Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/scripts/kconfig/lexer.l b/scripts/kconfig/lexer.l index cc386e4436834..2c2b3e6f248ca 100644 --- a/scripts/kconfig/lexer.l +++ b/scripts/kconfig/lexer.l @@ -302,8 +302,11 @@ static char *expand_token(const char *in, size_t n) new_string(); append_string(in, n); - /* get the whole line because we do not know the end of token. */ - while ((c = input()) != EOF) { + /* + * get the whole line because we do not know the end of token. + * input() returns 0 (not EOF!) when it reachs the end of file. + */ + while ((c = input()) != 0) { if (c == '\n') { unput(c); break;