Patch "x86/pkeys/selftests: Fix pkey exhaustion test off-by-one" has been added to the 4.16-stable tree

Patch "x86/pkeys/selftests: Fix pkey exhaustion test off-by-one" has been added to the 4.16-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    x86/pkeys/selftests: Fix pkey exhaustion test off-by-one

to the 4.16-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-pkeys-selftests-fix-pkey-exhaustion-test-off-by-one.patch
and it can be found in the queue-4.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Sun Jun 17 12:07:34 CEST 2018
From: Dave Hansen <dave.hansen@linux.intel.com>
Date: Wed, 9 May 2018 10:13:50 -0700
Subject: x86/pkeys/selftests: Fix pkey exhaustion test off-by-one

From: Dave Hansen <dave.hansen@linux.intel.com>

[ Upstream commit f50b4878329ab61d8e05796f655adeb6f5fb57c6 ]

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: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171350.E1656B95@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 tools/testing/selftests/x86/protection_keys.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/tools/testing/selftests/x86/protection_keys.c
+++ b/tools/testing/selftests/x86/protection_keys.c
@@ -1163,12 +1163,15 @@ 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]);


Patches currently in stable-queue which might be from dave.hansen@linux.intel.com are

queue-4.16/x86-pkeys-selftests-factor-out-instruction-page.patch
queue-4.16/x86-pkeys-selftests-fix-pointer-math.patch
queue-4.16/x86-pkeys-selftests-adjust-the-self-test-to-fresh-distros-that-export-the-pkeys-abi.patch
queue-4.16/x86-pkeys-selftests-add-a-test-for-pkey-0.patch
queue-4.16/x86-pkeys-selftests-stop-using-assert.patch
queue-4.16/x86-pkeys-selftests-save-off-prot-for-allocations.patch
queue-4.16/x86-pkeys-selftests-remove-dead-debugging-code-fix-dprint_in_signal.patch
queue-4.16/x86-mpx-selftests-adjust-the-self-test-to-fresh-distros-that-export-the-mpx-abi.patch
queue-4.16/x86-pkeys-selftests-add-prot_exec-test.patch
queue-4.16/x86-pkeys-selftests-allow-faults-on-unknown-keys.patch
queue-4.16/x86-pkeys-selftests-give-better-unexpected-fault-error-messages.patch
queue-4.16/x86-pkeys-selftests-avoid-printf-in-signal-deadlocks.patch
queue-4.16/x86-pkeys-selftests-fix-pkey-exhaustion-test-off-by-one.patch