x86/pkeys/selftests: Fix pointer math

BugLink: http://bugs.launchpad.net/bugs/1794889
[ Upstream commit 3d64f4ed15c3c53dba4c514bf59c334464dee373 ]

We dump out the entire area of the siginfo where the si_pkey_ptr is
supposed to be.  But, we do some math on the poitner, which is a u32.
We intended to do byte math, not u32 math on the pointer.

Cast it over to a u8* so it works.

Also, move this block of code to below th si_code check.  It doesn't
hurt anything, but the si_pkey field is gibberish for other signal
types.

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/20180509171352.9BE09819@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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/tools/testing/selftests/x86/protection_keys.c b/tools/testing/selftests/x86/protection_keys.c
index 55a4e349a45ed2d8179b7394ba4a442f167d62a0..ee8176358d123977353c96040a4a24d87adf00ea 100644 (file)
--- a/tools/testing/selftests/x86/protection_keys.c
+++ b/tools/testing/selftests/x86/protection_keys.c
@@ -303,13 +303,6 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
                dump_mem(pkru_ptr - 128, 256);
        pkey_assert(*pkru_ptr);
 
-       si_pkey_ptr = (u32 *)(((u8 *)si) + si_pkey_offset);
-       dprintf1("si_pkey_ptr: %p\n", si_pkey_ptr);
-       dump_mem(si_pkey_ptr - 8, 24);
-       siginfo_pkey = *si_pkey_ptr;
-       pkey_assert(siginfo_pkey < NR_PKEYS);
-       last_si_pkey = siginfo_pkey;
-
        if ((si->si_code == SEGV_MAPERR) ||
            (si->si_code == SEGV_ACCERR) ||
            (si->si_code == SEGV_BNDERR)) {
@@ -317,6 +310,13 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
                exit(4);
        }
 
+       si_pkey_ptr = (u32 *)(((u8 *)si) + si_pkey_offset);
+       dprintf1("si_pkey_ptr: %p\n", si_pkey_ptr);
+       dump_mem((u8 *)si_pkey_ptr - 8, 24);
+       siginfo_pkey = *si_pkey_ptr;
+       pkey_assert(siginfo_pkey < NR_PKEYS);
+       last_si_pkey = siginfo_pkey;
+
        dprintf1("signal pkru from xsave: %08x\n", *pkru_ptr);
        /* need __rdpkru() version so we do not do shadow_pkru checking */
        dprintf1("signal pkru from  pkru: %08x\n", __rdpkru());