From: Max Kellermann max.kellermann@ionos.com
[ 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@kernel.org: 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@ionos.com Signed-off-by: Masahiro Yamada masahiroy@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- scripts/mod/modpost.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 267b9a0a3abcd..9106fe7579466 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1050,7 +1050,9 @@ 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))