[PATCH 2/4] selftests/vm/pkeys: Handle negative sys_pkey_alloc() return code

Dave Hansen
2021-06-11T16:42:02Z

The alloc_pkey() sefltest function wraps the sys_pkey_alloc() system
call. On success, it updates its "shadow" register value because
sys_pkey_alloc() updates the real register.

But, the success check is wrong. pkey_alloc() considers any
non-zero return code to indicate success where the pkey register
will be modified. This fails to take negative return codes into
account.

Consider only a positive return value as a successful call.

Fixes: 5f23f6d082a9 ("x86/pkeys: Add self-tests")
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "Desnes A. Nunes do Rosario" <desnesn@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Suchanek <msuchanek@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: x86@kernel.org
---

b/tools/testing/selftests/vm/protection_keys.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN tools/testing/selftests/vm/protection_keys.c~selftests_vm_pkeys_ret-code tools/testing/selftests/vm/protection_keys.c
--- a/tools/testing/selftests/vm/protection_keys.c~selftests_vm_pkeys_ret-code 2021-06-11 09:41:32.448468063 -0700
+++ b/tools/testing/selftests/vm/protection_keys.c 2021-06-11 09:41:32.453468063 -0700
@@ -510,7 +510,7 @@ int alloc_pkey(void)
" shadow: 0x%016llx\n",
__func__, __LINE__, ret, __read_pkey_reg(),
shadow_pkey_reg);
- if (ret) {
+ if (ret > 0) {
/* clear both the bits: */
shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, ret,
~PKEY_MASK);
_