linux/kernel/kcsan
Kees Cook 795469820c 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: Nathan Chancellor <nathan@kernel.org>
Fixes: 69050f8d6d ("treewide: Replace kmalloc with kmalloc_obj for non-scalar types")
Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-26 09:54:08 -08:00
..
.kunitconfig kcsan: test: Add a .kunitconfig to run KCSAN tests 2022-07-22 09:22:59 -06:00
core.c kcsan: Don't expect 64 bits atomic builtins from 32 bits architectures 2023-06-09 23:29:50 +10:00
debugfs.c kcsan: Remove redundant call of kallsyms_lookup_name() 2024-10-14 16:44:56 +02:00
encoding.h kcsan: Add missing license and copyright headers 2021-03-08 14:27:43 -08:00
kcsan.h kcsan: Add ability to pass instruction pointer of access to reporting 2021-09-13 16:41:19 -07:00
kcsan_test.c kcsan: test: Adjust "expect" allocation type for kmalloc_obj 2026-02-26 09:54:08 -08:00
Makefile kcsan: Enable context analysis 2026-01-05 16:43:35 +01:00
permissive.h kcsan: permissive: Ignore data-racy 1-bit value changes 2021-07-20 13:49:44 -07:00
report.c kcsan: Enable context analysis 2026-01-05 16:43:35 +01:00
selftest.c mm: delete checks for xor_unlock_is_negative_byte() 2023-10-18 14:34:17 -07:00