Messages in this thread Patch in this message | | | Subject | [PATCH 6/9] x86, pkeys, selftests: fix pkey exhaustion test off-by-one | From | Dave Hansen <> | Date | Fri, 23 Mar 2018 11:09:14 -0700 |
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From: Dave Hansen <dave.hansen@linux.intel.com>
In our "exhaust all pkeys" test, we make sure that there is the expected number available. Turns out that the test did not cover the execute-only key, but discussed it anyway. It did *not* discuss the test-allocated key.
Now that we have a test for the mprotect(PROT_EXEC) case, this off-by-one issue showed itself. Correct the off-by- one and add the explanation for the case we missed.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Michael Ellermen <mpe@ellerman.id.au> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Shuah Khan <shuah@kernel.org> ---
b/tools/testing/selftests/x86/protection_keys.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff -puN tools/testing/selftests/x86/protection_keys.c~pkeys-selftests-exhaust-off-by-one tools/testing/selftests/x86/protection_keys.c --- a/tools/testing/selftests/x86/protection_keys.c~pkeys-selftests-exhaust-off-by-one 2018-03-21 15:47:50.910198920 -0700 +++ b/tools/testing/selftests/x86/protection_keys.c 2018-03-21 15:47:50.914198920 -0700 @@ -1155,12 +1155,15 @@ void test_pkey_alloc_exhaust(int *ptr, u pkey_assert(i < NR_PKEYS*2); /* - * There are 16 pkeys supported in hardware. One is taken - * up for the default (0) and another can be taken up by - * an execute-only mapping. Ensure that we can allocate - * at least 14 (16-2). + * There are 16 pkeys supported in hardware. Three are + * allocated by the time we get here: + * 1. The default key (0) + * 2. One possibly consumed by an execute-only mapping. + * 3. One allocated by the test code and passed in via + * 'pkey' to this function. + * Ensure that we can allocate at least another 13 (16-3). */ - pkey_assert(i >= NR_PKEYS-2); + pkey_assert(i >= NR_PKEYS-3); for (i = 0; i < nr_allocated_pkeys; i++) { err = sys_pkey_free(allocated_pkeys[i]); _
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