This is a note to let you know that I've just added the patch titled
modpost: fix null pointer dereference
to the 6.6-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-null-pointer-dereference.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9f8d6ac55e1dd2f10563b51a7e23a542fb83aa59
Author: Max Kellermann <max.kellermann@xxxxxxxxx>
Date: Thu Feb 15 15:13:21 2024 +0100
modpost: fix null pointer dereference
[ Upstream commit 23dfd914d2bfc4c9938b0084dffd7105de231d98 ]
If the find_fromsym() call fails and returns NULL, the warn() call
will dereference this NULL pointer and cause the program to crash.
This happened when I tried to build with "test_user_copy" module.
With this fix, it prints lots of warnings like this:
WARNING: modpost: lib/test_user_copy: section mismatch in reference: (unknown)+0x4 (section: .text.fixup) -> (unknown) (section: .init.text)
masahiroy@xxxxxxxxxx:
The issue is reproduced with ARCH=arm allnoconfig + CONFIG_MODULES=y +
CONFIG_RUNTIME_TESTING_MENU=y + CONFIG_TEST_USER_COPY=m
Signed-off-by: Max Kellermann <max.kellermann@xxxxxxxxx>
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 7d53942445d75..269bd79bcd9ad 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1098,7 +1098,9 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf,
sec_mismatch_count++;
warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
- modname, fromsym, (unsigned int)(faddr - from->st_value), fromsec, tosym, tosec);
+ modname, fromsym,
+ (unsigned int)(faddr - (from ? from->st_value : 0)),
+ fromsec, tosym, tosec);
if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
if (match(tosec, mismatch->bad_tosec))
