x86/signals: Fix lower/upper bound reporting in compat siginfo

Put the right values from the original siginfo into the
userspace compat-siginfo.

This fixes the 32-bit MPX "tabletest" testcase on 64-bit kernels.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v4.8+
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: a4455082dc6f0 ('x86/signals: Add missing signal_compat code for x86 features')
Link: http://lkml.kernel.org/r/1491322501-5054-1-git-send-email-joro@8bytes.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/signal_compat.c

@@ -151,8 +151,8 @@ int __copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from,
 
 				if (from->si_signo == SIGSEGV) {
 					if (from->si_code == SEGV_BNDERR) {
-						compat_uptr_t lower = (unsigned long)&to->si_lower;
-						compat_uptr_t upper = (unsigned long)&to->si_upper;
+						compat_uptr_t lower = (unsigned long)from->si_lower;
+						compat_uptr_t upper = (unsigned long)from->si_upper;
 						put_user_ex(lower, &to->si_lower);
 						put_user_ex(upper, &to->si_upper);
 					}