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    Subject[PATCH 01/13] x86/pkeys/selftests: Give better unexpected fault error messages
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    From: Dave Hansen <dave.hansen@linux.intel.com>

    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 <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, 7 insertions(+), 6 deletions(-)

    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);
    _
    \
     
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      Last update: 2018-05-09 19:21    [W:4.190 / U:0.048 seconds]
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