Patch "x86/pkeys/selftests: Give better unexpected fault error messages" has been added to the 4.14-stable tree

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

x86/pkeys/selftests: Give better unexpected fault error messages

to the 4.14-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-give-better-unexpected-fault-error-messages.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dave Hansen <[email protected]>
Date: Wed, 9 May 2018 10:13:38 -0700
Subject: x86/pkeys/selftests: Give better unexpected fault error messages

From: Dave Hansen <[email protected]>

[ Upstream commit 55556b0b2016806b2e16a20b62d143383983a34a ]

do_not_expect_pk_fault() is a helper that we call when we do not expect a PK fault to have occurred. But, it is a function, which means that it obscures the line numbers from pkey_assert(). It also gives no details.

Replace it with an implementation that gives nice line numbers and also lets callers pass in a more descriptive message about what happened that caused the unexpected fault.

---
 tools/testing/selftests/x86/protection_keys.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

@@ -954,10 +954,11 @@ void expected_pk_fault(int pkey)
 	last_si_pkey = -1;
 }
 
-void do_not_expect_pk_fault(void)
-{
-	pkey_assert(last_pkru_faults == pkru_faults);
-}
+#define do_not_expect_pk_fault(msg)	do {			\
+	if (last_pkru_faults != pkru_faults)			\
+		dprintf0("unexpected PK fault: %s\n", msg);	\
+	pkey_assert(last_pkru_faults == pkru_faults);		\
+} while (0)
 
 int test_fds[10] = { -1 };
 int nr_test_fds;

@@ -1243,7 +1244,7 @@ void test_ptrace_of_child(int *ptr, u16
 	pkey_assert(ret != -1);
 	/* Now access from the current task, and expect NO exception: */
 	peek_result = read_ptr(plain_ptr);
-	do_not_expect_pk_fault();
+	do_not_expect_pk_fault("read plain pointer after ptrace");
 
 	ret = ptrace(PTRACE_DETACH, child_pid, ignored, 0);
 	pkey_assert(ret != -1);

@@ -1287,7 +1288,7 @@ void test_executing_on_unreadable_memory
 	 */
 	madvise(p1, PAGE_SIZE, MADV_DONTNEED);
 	lots_o_noops_around_write(&scratch);
-	do_not_expect_pk_fault();
+	do_not_expect_pk_fault("executing on PROT_EXEC memory");
 	ptr_contents = read_ptr(p1);
 	dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
 	expected_pk_fault(pkey);

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/x86-pkeys-selftests-factor-out-instruction-page.patch queue-4.14/x86-pkeys-selftests-fix-pointer-math.patch queue-4.14/x86-pkeys-selftests-adjust-the-self-test-to-fresh-distros-that-export-the-pkeys-abi.patch queue-4.14/x86-pkeys-selftests-add-a-test-for-pkey-0.patch queue-4.14/x86-pkeys-selftests-stop-using-assert.patch queue-4.14/x86-pkeys-selftests-save-off-prot-for-allocations.patch queue-4.14/x86-pkeys-selftests-remove-dead-debugging-code-fix-dprint_in_signal.patch queue-4.14/x86-mpx-selftests-adjust-the-self-test-to-fresh-distros-that-export-the-mpx-abi.patch queue-4.14/x86-pkeys-selftests-add-prot_exec-test.patch queue-4.14/x86-pkeys-selftests-allow-faults-on-unknown-keys.patch queue-4.14/x86-pkeys-selftests-give-better-unexpected-fault-error-messages.patch queue-4.14/x86-pkeys-selftests-fix-pkey-exhaustion-test-off-by-one.patch