Dereferencing a null pointer on Clang is not a good idea - it will entirely optimise out the dereference. Make the pointer volatile to force the access (and fault). Reported-by: kernel test robot <lkp@xxxxxxxxx> Closes: https://lore.kernel.org/oe-kbuild-all/202412140850.4TW4YBqc-lkp@xxxxxxxxx/ Signed-off-by: Kevin Brodsky <kevin.brodsky@xxxxxxx> --- Hi Andrew, Another fixup for an issue reported by the LKP CI (building with Clang instead of GCC). This should be squashed into the patch I'm replying to: "selftests/mm: Fix -Warray-bounds warnings in pkey_sighandler_tests" Cheers, - Kevin Cc: aruna.ramakrishna@xxxxxxxxxx Cc: catalin.marinas@xxxxxxx Cc: dave.hansen@xxxxxxxxxxxxxxx Cc: joey.gouly@xxxxxxx Cc: keith.lucas@xxxxxxxxxx Cc: ryan.roberts@xxxxxxx Cc: shuah@xxxxxxxxxx Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: linux-kselftest@xxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx Cc: x86@xxxxxxxxxx --- tools/testing/selftests/mm/pkey_sighandler_tests.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/mm/pkey_sighandler_tests.c b/tools/testing/selftests/mm/pkey_sighandler_tests.c index 17bbfcd552c6..1ac8c8809880 100644 --- a/tools/testing/selftests/mm/pkey_sighandler_tests.c +++ b/tools/testing/selftests/mm/pkey_sighandler_tests.c @@ -161,7 +161,7 @@ static void *thread_segv_with_pkey0_disabled(void *ptr) __write_pkey_reg(pkey_reg_restrictive_default()); /* Segfault (with SEGV_MAPERR) */ - *(int *)NULL = 1; + *(volatile int *)NULL = 1; return NULL; } @@ -192,7 +192,7 @@ static void *thread_segv_maperr_ptr(void *ptr) __write_pkey_reg(pkey_reg); /* Segfault */ - *(int *)NULL = 1; + *(volatile int *)NULL = 1; syscall_raw(SYS_exit, 0, 0, 0, 0, 0, 0); return NULL; } -- 2.47.0
