x86/apic: Remove noisy zero-mask warning from default_send_IPI_mask_logical()

BugLink: http://bugs.launchpad.net/bugs/1100202

Since circa 3.5, we've had dozens of reports of people hitting
this warning. Forwarded reports have been met with silence, so
just remove the warning if no-one cares.

Example reports:

  https://bugzilla.redhat.com/show_bug.cgi?id=797687
  https://bugzilla.redhat.com/show_bug.cgi?id=867174
  https://bugzilla.redhat.com/show_bug.cgi?id=894865

Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20130118175847.GA27662@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit e3f0f36ddf1b2743a0d4ea312996536a9c37e1c7)
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
signal: always clear sa_restorer on execve

CVE-2013-0914

BugLink: http://bugs.launchpad.net/bugs/1153813

When the new signal handlers are set up, the location of sa_restorer is
not cleared, leaking a parent process's address space location to
children.  This allows for a potential bypass of the parent's ASLR by
examining the sa_restorer value returned when calling sigaction().

Based on what should be considered "secret" about addresses, it only
matters across the exec not the fork (since the VMAs haven't changed
until the exec).  But since exec sets SIG_DFL and keeps sa_restorer,
this is where it should be fixed.

Given the few uses of sa_restorer, a "set" function was not written
since this would be the only use.  Instead, we use
__ARCH_HAS_SA_RESTORER, as already done in other places.

Example of the leak before applying this patch:

  $ cat /proc/$$/maps
  ...
  7fb9f3083000-7fb9f3238000 r-xp 00000000 fd:01 404469 .../libc-2.15.so
  ...
  $ ./leak
  ...
  7f278bc74000-7f278be29000 r-xp 00000000 fd:01 404469 .../libc-2.15.so
  ...
  1 0 (nil) 0x7fb9f30b94a0
  2 4000000 (nil) 0x7f278bcaa4a0
  3 4000000 (nil) 0x7f278bcaa4a0
  4 0 (nil) 0x7fb9f30b94a0
  ...

[akpm@linux-foundation.org: use SA_RESTORER for backportability]
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Emese Revfy <re.emese@gmail.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Julien Tinnes <jln@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 2ca39528c01a933f6689cd6505ce65bd6d68a530)
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-3.5.0-27.43

Signed-off-by: Steve Conklin <sconklin@canonical.com>
UBUNTU: Ubuntu-3.5.0-27.44

Signed-off-by: Steve Conklin <sconklin@canonical.com>
UBUNTU: Ubuntu-3.5.0-27.45

Signed-off-by: Steve Conklin <sconklin@canonical.com>
UBUNTU: [Config] Created LTS backport branch

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.4.0-3.7

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.4.0-4.9

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.4.0-5.11

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-1.1

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-2.2

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-3.3

Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-4.4

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-5.5

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-6.6

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-7.7

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-8.8

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-9.9

Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-10.10

Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
UBUNTU: Ubuntu-lts-3.5.0-11.11

Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>