Commit 79546982 authored by Kees Cook's avatar Kees Cook
Browse files

kcsan: test: Adjust "expect" allocation type for kmalloc_obj 



The call to kmalloc_obj(observed.lines) returns "char (*)[3][512]",
a pointer to the whole 2D array. But "expect" wants to be "char (*)[512]",
the decayed pointer type, as if it were observed.lines itself (though
without the "3" bounds). This produces the following build error:

../kernel/kcsan/kcsan_test.c: In function '__report_matches':
../kernel/kcsan/kcsan_test.c:171:16: error: assignment to 'char (*)[512]' from incompatible pointer type 'char (*)[3][512]'
[-Wincompatible-pointer-types]
  171 |         expect = kmalloc_obj(observed.lines);
      |                ^

Instead of changing the "expect" type to "char (*)[3][512]" and
requiring a dereference at each use (e.g. "(expect*)[0]"), just
explicitly cast the return to the desired type.

Note that I'm intentionally not switching back to byte-based "kmalloc"
here because I cannot find a way for the Coccinelle script (which will
be used going forward to catch future conversions) to exclude this case.

Tested with:

$ ./tools/testing/kunit/kunit.py run \
	--kconfig_add CONFIG_DEBUG_KERNEL=y \
	--kconfig_add CONFIG_KCSAN=y \
	--kconfig_add CONFIG_KCSAN_KUNIT_TEST=y \
	--arch=x86_64 --qemu_args '-smp 2' kcsan

Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Fixes: 69050f8d ("treewide: Replace kmalloc with kmalloc_obj for non-scalar types")
Signed-off-by: default avatarKees Cook <kees@kernel.org>
parent 4b44cbb2

kernel/kcsan/kcsan_test.c

+1 −1
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ static bool __report_matches(const struct expect_report *r) 
	if (!report_available())

		return false;



	expect = kmalloc_obj(observed.lines);

	expect = (typeof(expect))kmalloc_obj(observed.lines);

	if (WARN_ON(!expect))

		return false;