[01/13] x86/pkeys/selftests: Give better unexpected fault error messages

Commit Message

Dave Hansen May 9, 2018, 5:13 p.m. UTC

From: Dave Hansen <[e-mail]>

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.

Signed-off-by: Dave Hansen <[e-mail]>
Cc: Ram Pai <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Michael Ellermen <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Shuah Khan <[e-mail]>
---

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

Patch

diff -puN tools/testing/selftests/x86/protection_keys.c~pkeys-selftests-give-better-pkey-fault-errors tools/testing/selftests/x86/protection_keys.c
--- a/tools/testing/selftests/x86/protection_keys.c~pkeys-selftests-give-better-pkey-fault-errors	2018-05-09 09:20:18.202698408 -0700
+++ b/tools/testing/selftests/x86/protection_keys.c	2018-05-09 09:20:18.205698408 -0700
@@ -939,10 +939,11 @@  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;
@@ -1228,7 +1229,7 @@  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);
@@ -1272,7 +1273,7 @@  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);