Pull module fixes from Rusty Russell:
 "Fixed one missing place for the new taint flag, and remove a warning
  giving only false positives (now we finally figured out why)"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  module: remove warning about waiting module removal.
  Fix: tracing: use 'E' instead of 'X' for unsigned module taint flag

A race exists between module loading and enabling of function tracer.

	CPU 1				CPU 2
	-----				-----
  load_module()
   module->state = MODULE_STATE_COMING

				register_ftrace_function()
				 mutex_lock(&ftrace_lock);
				 ftrace_startup()
				  update_ftrace_function();
				   ftrace_arch_code_modify_prepare()
				    set_all_module_text_rw();
				   <enables-ftrace>
				    ftrace_arch_code_modify_post_process()
				     set_all_module_text_ro();

				[ here all module text is set to RO,
				  including the module that is
				  loading!! ]

   blocking_notifier_call_chain(MODULE_STATE_COMING);
    ftrace_init_module()

     [ tries to modify code, but it's RO, and fails!
       ftrace_bug() is called]

When this race happens, ftrace_bug() will produces a nasty warning and
all of the function tracing features will be disabled until reboot.

The simple solution is to treate module load the same way the core
kernel is treated at boot. To hardcode the ftrace function modification
of converting calls to mcount into nops. This is done in init/main.c
there's no reason it could not be done in load_module(). This gives
a better control of the changes and doesn't tie the state of the
module to its notifiers as much. Ftrace is special, it needs to be
treated as such.

The reason this would work, is that the ftrace_module_init() would be
called while the module is in MODULE_STATE_UNFORMED, which is ignored
by the set_all_module_text_ro() call.

Link: http://lkml.kernel.org/r/1395637826-3312-1-git-send-email-indou.takao@jp.fujitsu.com

Reported-by: Takao Indoh <indou.takao@jp.fujitsu.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@vger.kernel.org # 2.6.38+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

We remove the waiting module removal in commit 3f2b9c9cdf38 (September
2013), but it turns out that modprobe in kmod (< version 16) was
asking for waiting module removal.  No one noticed since modprobe would
check for 0 usage immediately before trying to remove the module, and
the race is unlikely.

However, it means that anyone running old (but not ancient) kmod
versions is hitting the printk designed to see if anyone was running
"rmmod -w".  All reports so far have been false positives, so remove
the warning.

Fixes: 3f2b9c9cdf389e303b2273679af08aab5f153517
Reported-by: Valerio Vanni <valerio.vanni@inwind.it>
Cc: Elliott, Robert (Server Storage) <Elliott@hp.com>
Cc: stable@kernel.org
Acked-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

The initialization of a structure is not subject to synchronization.
The use of __this_cpu would trigger a false positive with the additional
preemption checks for __this_cpu ops.

So simply disable the check through the use of raw_cpu ops.

Trace:

  __this_cpu_write operation in preemptible [00000000] code: modprobe/286
  caller is __this_cpu_preempt_check+0x38/0x60
  CPU: 3 PID: 286 Comm: modprobe Tainted: GF            3.12.0-rc4+ #187
  Call Trace:
    dump_stack+0x4e/0x82
    check_preemption_disabled+0xec/0x110
    __this_cpu_preempt_check+0x38/0x60
    load_module+0xcfd/0x2650
    SyS_init_module+0xa6/0xd0
    tracesys+0xe1/0xe6

Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull module updates from Rusty Russell:
 "Nothing major: the stricter permissions checking for sysfs broke a
  staging driver; fix included.  Greg KH said he'd take the patch but
  hadn't as the merge window opened, so it's included here to avoid
  breaking build"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  staging: fix up speakup kobject mode
  Use 'E' instead of 'X' for unsigned module taint flag.
  VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.
  kallsyms: fix percpu vars on x86-64 with relocation.
  kallsyms: generalize address range checking
  module: LLVMLinux: Remove unused function warning from __param_check macro
  Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
  module: remove MODULE_GENERIC_TABLE
  module: allow multiple calls to MODULE_DEVICE_TABLE() per module
  module: use pr_cont

Pull x86 LTO changes from Peter Anvin:
 "More infrastructure work in preparation for link-time optimization
  (LTO).  Most of these changes is to make sure symbols accessed from
  assembly code are properly marked as visible so the linker doesn't
  remove them.

  My understanding is that the changes to support LTO are still not
  upstream in binutils, but are on the way there.  This patchset should
  conclude the x86-specific changes, and remaining patches to actually
  enable LTO will be fed through the Kbuild tree (other than keeping up
  with changes to the x86 code base, of course), although not
  necessarily in this merge window"

* 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  Kbuild, lto: Handle basic LTO in modpost
  Kbuild, lto: Disable LTO for asm-offsets.c
  Kbuild, lto: Add a gcc-ld script to let run gcc as ld
  Kbuild, lto: add ld-version and ld-ifversion macros
  Kbuild, lto: Drop .number postfixes in modpost
  Kbuild, lto, workaround: Don't warn for initcall_reference in modpost
  lto: Disable LTO for sys_ni
  lto: Handle LTO common symbols in module loader
  lto, workaround: Add workaround for initcall reordering
  lto: Make asmlinkage __visible
  x86, lto: Disable LTO for the x86 VDSO
  initconst, x86: Fix initconst mistake in ts5500 code
  initconst: Fix initconst mistake in dcdbas
  asmlinkage: Make trace_hardirqs_on/off_caller visible
  asmlinkage, x86: Fix 32bit memcpy for LTO
  asmlinkage Make __stack_chk_failed and memcmp visible
  asmlinkage: Mark rwsem functions that can be called from assembler asmlinkage
  asmlinkage: Make main_extable_sort_needed visible
  asmlinkage, mutex: Mark __visible
  asmlinkage: Make trace_hardirq visible
  ...

Takashi Iwai <tiwai@suse.de> says:
> The letter 'X' has been already used for SUSE kernels for very long
> time, to indicate the external supported modules.  Can the new flag be
> changed to another letter for avoiding conflict...?
> (BTW, we also use 'N' for "no support", too.)

Note: this code should be cleaned up, so we don't have such maps in
three places!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Rename TAINT_UNSAFE_SMP to TAINT_CPU_OUT_OF_SPEC, so we can repurpose
the flag to encompass a wider range of pushing the CPU beyond its
warrany.

Signed-off-by: Dave Jones <davej@fedoraproject.org>
Link: http://lkml.kernel.org/r/20140226154949.GA770@redhat.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Users have reported being unable to trace non-signed modules loaded
within a kernel supporting module signature.

This is caused by tracepoint.c:tracepoint_module_coming() refusing to
take into account tracepoints sitting within force-loaded modules
(TAINT_FORCED_MODULE). The reason for this check, in the first place, is
that a force-loaded module may have a struct module incompatible with
the layout expected by the kernel, and can thus cause a kernel crash
upon forced load of that module on a kernel with CONFIG_TRACEPOINTS=y.

Tracepoints, however, specifically accept TAINT_OOT_MODULE and
TAINT_CRAP, since those modules do not lead to the "very likely system
crash" issue cited above for force-loaded modules.

With kernels having CONFIG_MODULE_SIG=y (signed modules), a non-signed
module is tainted re-using the TAINT_FORCED_MODULE taint flag.
Unfortunately, this means that Tracepoints treat that module as a
force-loaded module, and thus silently refuse to consider any tracepoint
within this module.

Since an unsigned module does not fit within the "very likely system
crash" category of tainting, add a new TAINT_UNSIGNED_MODULE taint flag
to specifically address this taint behavior, and accept those modules
within Tracepoints. We use the letter 'X' as a taint flag character for
a module being loaded that doesn't know how to sign its name (proposed
by Steven Rostedt).

Also add the missing 'O' entry to trace event show_module_flags() list
for the sake of completeness.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
NAKed-by: Ingo Molnar <mingo@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: David Howells <dhowells@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

When dumping loaded modules, we print them one by one in separate
printks. Let's use pr_cont as they are continuation prints.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>