We're forgetting to reenable local interrupts on an error path.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Reported-by: NJosh Boyer <jwboyer@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The old SRCU implementation loads sp->completed within an
RCU-sched section, courtesy of preempt_disable().  This was required
due to the use of synchronize_sched() in the old implemenation's
synchronize_srcu().  However, the new implementation does not rely
on synchronize_sched(), so it in turn does not require the load of
sp->completed and the ->c[] counter to be in a single preempt-disabled
region of code.  This commit therefore moves the sp->completed access
outside of the preempt-disabled region and applies ACCESS_ONCE().

The resulting code is almost as the same as before, but it removes the
now-misleading rcu_dereference_index_check() call.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Because synchronize_srcu_expedited() no longer uses
synchronize_rcu_sched_expedited(), synchronize_srcu_expedited() no longer
indirectly acquires any CPU-hotplug-related locks.  This commit therefore
updates the comments accordingly.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The core of SRCU is changed, but synchronize_srcu()'s comments describe
the old algorithm.  This commit therefore updates them to match the
new algorithm.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Pack six lines of code into two lines.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Although synchronize_srcu() can sleep, it will not sleep if the fast
path succeeds, which means that illegal use of synchronize_rcu()
might go unnoticed.  This commit therefore adds might_sleep(), which
unconditionally catches illegal use of synchronize_rcu() from atomic
context.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

This commit replaces disabling of preemption and decrement of a per-CPU
variable with this_cpu_dec(), which avoids preemption disabling on x86
and shortens the code on all platforms.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The uses of trace_clock_local() are dead code when CONFIG_RCU_TRACE=n,
but some compilers might nevertheless generate code calling this function.
This commit therefore ensures that trace_clock_local() is invoked only
when CONFIG_RCU_TRACE=y.
Reported-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

When we have group with mixed events (hw/sw) we want to end up
with group leader being in hw context. So if group leader is
initialy sw event, we move all the events under hw context.

The move is done for each event by removing it from its context
and adding it back into proper one. As a part of the removal the
event is automatically disabled, which is not what we want at
this stage of creating groups.

The fix is to initialize event state after removal from sw
context.

This fix resulted from the following discussion:

  http://thread.gmane.org/gmane.linux.kernel.perf.user/1144Reported-by: NAndreas Hollmann <hollmann@in.tum.de>
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vince@deater.net>
Link: http://lkml.kernel.org/r/1359714225-4231-1-git-send-email-jolsa@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This reverts commit daee7797.

I'll requeue this after the console locking fixes, so lockdep
is useful again for people until fbcon is fixed.
Signed-off-by: NDave Airlie <airlied@redhat.com>

A number of kthreads have been added to rcutorture, but the shuffler
task was not informed of them, and thus did not shuffle them.  This
commit therefore adds the requisite shuffling, and, while in the area
fixes up some whitespace issues.

However, the shuffling is intended to keep randomly selected CPUs
idle, which means that the RCU priority boosting kthreads need to
avoid waking up every jiffy.  This commit also makes that fix.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Tiny RCU has historically omitted RCU CPU stall warnings in order to
reduce memory requirements, however, lack of these warnings caused
Thomas Gleixner some debugging pain recently.  Therefore, this commit
adds RCU CPU stall warnings to tiny RCU if RCU_TRACE=y.  This keeps
the memory footprint small, while still enabling CPU stall warnings
in kernels built to enable them.

Updated to include Josh Triplett's suggested use of RCU_STALL_COMMON
config variable to simplify #if expressions.
Reported-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

I get the following warning every day with v3.7, once or
twice a day:

  [ 2235.186027] WARNING: at /mnt/sda7/kernel/linux/arch/x86/kernel/apic/ipi.c:109 default_send_IPI_mask_logical+0x2f/0xb8()

As explained by Linus as well:

 |
 | Once we've done the "list_add_rcu()" to add it to the
 | queue, we can have (another) IPI to the target CPU that can
 | now see it and clear the mask.
 |
 | So by the time we get to actually send the IPI, the mask might
 | have been cleared by another IPI.
 |

This patch also fixes a system hang problem, if the data->cpumask
gets cleared after passing this point:

        if (WARN_ONCE(!mask, "empty IPI mask"))
                return;

then the problem in commit 83d349f3 ("x86: don't send an IPI to
the empty set of CPU's") will happen again.
Signed-off-by: NWang YanQing <udknight@gmail.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Acked-by: NJan Beulich <jbeulich@suse.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: peterz@infradead.org
Cc: mina86@mina86.org
Cc: srivatsa.bhat@linux.vnet.ibm.com
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/20130126075357.GA3205@udknight
[ Tidied up the changelog and the comment in the code. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

This subsystem lacks many explanations on its purpose and
design. Add these missing comments.

v4: Document function parameter to be more kernel-doc
friendly, as per Namhyung suggestion.
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

As context tracking subsystem evolved, it stopped using ignore_user_qs
and in_user defined in the rcu_dynticks structure.  This commit therefore
removes them.
Signed-off-by: NLi Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>

Small grammar fix in rcutree comment regarding 'rcu_scheduler_active'
var.
Signed-off-by: NCody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

The type returned from atomic64_t can be either unsigned
long or unsigned long long, depending on the architecture.
Using a cast to unsigned long long lets us use the same
format string for all architectures.

Without this patch, building with scheduler debugging
enabled results in:

  kernel/sched/debug.c: In function 'print_cfs_rq':
  kernel/sched/debug.c:225:2: warning: format '%ld' expects argument of type 'long int', but argument 4 has type 'long long int' [-Wformat]
  kernel/sched/debug.c:225:2: warning: format '%ld' expects argument of type 'long int', but argument 3 has type 'long long int' [-Wformat]
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: linux-arm-kernel@list.infradead.org
Link: http://lkml.kernel.org/r/1359123276-15833-7-git-send-email-arnd@arndb.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

a4c96ae3 "sched: Unthrottle rt runqueues in
__disable_runtime()" turned the unthrottle_offline_cfs_rqs
function into a static symbol, which now triggers a warning
about it being potentially unused:

  kernel/sched/fair.c:2055:13: warning: 'unthrottle_offline_cfs_rqs' defined but not used [-Wunused-function]

Marking it __maybe_unused shuts up the gcc warning and lets the
compiler safely drop the function body when it's not being used.

To reproduce, build the ARM bcm2835_defconfig.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Peter Boonstoppel <pboonstoppel@nvidia.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Cc: linux-arm-kernel@list.infradead.org
Link: http://lkml.kernel.org/r/1359123276-15833-6-git-send-email-arnd@arndb.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

When the system has multiple domains do_sched_rt_period_timer()
can run on any CPU and may iterate over all rt_rq in
cpu_online_mask.  This means when balance_runtime() is run for a
given rt_rq that rt_rq may be in a different rd than the current
processor.  Thus if we use smp_processor_id() to get rd in
do_balance_runtime() we may borrow runtime from a rt_rq that is
not part of our rd.

This changes do_balance_runtime to get the rd from the passed in
rt_rq ensuring that we borrow runtime only from the correct rd
for the given rt_rq.

This fixes a BUG at kernel/sched/rt.c:687! in __disable_runtime
when we try reclaim runtime lent to other rt_rq but runtime has
been lent to a rt_rq in another rd.
Signed-off-by: NShawn Bohrer <sbohrer@rgmadvisors.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Acked-by: NMike Galbraith <bitbucket@online.de>
Cc: peterz@infradead.org
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/1358186131-29494-1-git-send-email-sbohrer@rgmadvisors.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Commit 083b804c ("async: use workqueue for worker pool") made it
possible that async jobs are moved from pending to running out-of-order.
While pending async jobs will be queued and dispatched for execution in
the same order, nothing guarantees they'll enter "1) move self to the
running queue" of async_run_entry_fn() in the same order.

Before the conversion, async implemented its own worker pool.  An async
worker, upon being woken up, fetches the first item from the pending
list, which kept the executing lists sorted.  The conversion to
workqueue was done by adding work_struct to each async_entry and async
just schedules the work item.  The queueing and dispatching of such work
items are still in order but now each worker thread is associated with a
specific async_entry and moves that specific async_entry to the
executing list.  So, depending on which worker reaches that point
earlier, which is non-deterministic, we may end up moving an async_entry
with larger cookie before one with smaller one.

This broke __lowest_in_progress().  running->domain may not be properly
sorted and is not guaranteed to contain lower cookies than pending list
when not empty.  Fix it by ensuring sort-inserting to the running list
and always looking at both pending and running when trying to determine
the lowest cookie.

Over time, the async synchronization implementation became quite messy.
We better restructure it such that each async_entry is linked to two
lists - one global and one per domain - and not move it when execution
starts.  There's no reason to distinguish pending and running.  They
behave the same for synchronization purposes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

wake_up_process() should never wakeup a TASK_STOPPED/TRACED task.
Change it to use TASK_NORMAL and add the WARN_ON().

TASK_ALL has no other users, probably can be killed.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

putreg() assumes that the tracee is not running and pt_regs_access() can
safely play with its stack.  However a killed tracee can return from
ptrace_stop() to the low-level asm code and do RESTORE_REST, this means
that debugger can actually read/modify the kernel stack until the tracee
does SAVE_REST again.

set_task_blockstep() can race with SIGKILL too and in some sense this
race is even worse, the very fact the tracee can be woken up breaks the
logic.

As Linus suggested we can clear TASK_WAKEKILL around the arch_ptrace()
call, this ensures that nobody can ever wakeup the tracee while the
debugger looks at it.  Not only this fixes the mentioned problems, we
can do some cleanups/simplifications in arch_ptrace() paths.

Probably ptrace_unfreeze_traced() needs more callers, for example it
makes sense to make the tracee killable for oom-killer before
access_process_vm().

While at it, add the comment into may_ptrace_stop() to explain why
ptrace_stop() still can't rely on SIGKILL and signal_pending_state().
Reported-by: NSalman Qazi <sqazi@google.com>
Reported-by: NSuleiman Souhlal <suleiman@google.com>
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Cleanup and preparation for the next change.

signal_wake_up(resume => true) is overused. None of ptrace/jctl callers
actually want to wakeup a TASK_WAKEKILL task, but they can't specify the
necessary mask.

Turn signal_wake_up() into signal_wake_up_state(state), reintroduce
signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up()
which adds __TASK_TRACED.

This way ptrace_signal_wake_up() can work "inside" ptrace_request()
even if the tracee doesn't have the TASK_WAKEKILL bit set.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If some other kernel subsystem has a module notifier, and adds a kprobe
to a ftrace mcount point (now that kprobes work on ftrace points),
when the ftrace notifier runs it will fail and disable ftrace, as well
as kprobes that are attached to ftrace points.

Here's the error:

 WARNING: at kernel/trace/ftrace.c:1618 ftrace_bug+0x239/0x280()
 Hardware name: Bochs
 Modules linked in: fat(+) stap_56d28a51b3fe546293ca0700b10bcb29__8059(F) nfsv4 auth_rpcgss nfs dns_resolver fscache xt_nat iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack lockd sunrpc ppdev parport_pc parport microcode virtio_net i2c_piix4 drm_kms_helper ttm drm i2c_core [last unloaded: bid_shared]
 Pid: 8068, comm: modprobe Tainted: GF            3.7.0-0.rc8.git0.1.fc19.x86_64 #1
 Call Trace:
  [<ffffffff8105e70f>] warn_slowpath_common+0x7f/0xc0
  [<ffffffff81134106>] ? __probe_kernel_read+0x46/0x70
  [<ffffffffa0180000>] ? 0xffffffffa017ffff
  [<ffffffffa0180000>] ? 0xffffffffa017ffff
  [<ffffffff8105e76a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff810fd189>] ftrace_bug+0x239/0x280
  [<ffffffff810fd626>] ftrace_process_locs+0x376/0x520
  [<ffffffff810fefb7>] ftrace_module_notify+0x47/0x50
  [<ffffffff8163912d>] notifier_call_chain+0x4d/0x70
  [<ffffffff810882f8>] __blocking_notifier_call_chain+0x58/0x80
  [<ffffffff81088336>] blocking_notifier_call_chain+0x16/0x20
  [<ffffffff810c2a23>] sys_init_module+0x73/0x220
  [<ffffffff8163d719>] system_call_fastpath+0x16/0x1b
 ---[ end trace 9ef46351e53bbf80 ]---
 ftrace failed to modify [<ffffffffa0180000>] init_once+0x0/0x20 [fat]
  actual: cc:bb:d2:4b:e1

A kprobe was added to the init_once() function in the fat module on load.
But this happened before ftrace could have touched the code. As ftrace
didn't run yet, the kprobe system had no idea it was a ftrace point and
simply added a breakpoint to the code (0xcc in the cc:bb:d2:4b:e1).

Then when ftrace went to modify the location from a call to mcount/fentry
into a nop, it didn't see a call op, but instead it saw the breakpoint op
and not knowing what to do with it, ftrace shut itself down.

The solution is to simply give the ftrace module notifier the max priority.
This should have been done regardless, as the core code ftrace modification
also happens very early on in boot up. This makes the module modification
closer to core modification.

Link: http://lkml.kernel.org/r/20130107140333.593683061@goodmis.org

Cc: stable@vger.kernel.org
Acked-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reported-by: NFrank Ch. Eigler <fche@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Commit 1fb9341a ("module: put modules in list much earlier") moved
some of the module initialization code around, and in the process
changed the exit paths too.  But for the duplicate export symbol error
case the change made the ddebug_cleanup path jump to after the module
mutex unlock, even though it happens with the mutex held.

Rusty has some patches to split this function up into some helper
functions, hopefully the mess of complex goto targets will go away
eventually.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The ia64 function "thread_matches()" has no users since commit
e868a55c ("[IA64] remove find_thread_for_addr()").  Remove it.

This allows us to make ptrace_check_attach() static to kernel/ptrace.c,
which is good since we'll need to change the semantics of it and fix up
all the callers.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If the default iosched is built as module, the kernel may deadlock
while trying to load the iosched module on device probe if the probing
was running off async.  This is because async_synchronize_full() at
the end of module init ends up waiting for the async job which
initiated the module loading.

 async A				modprobe

 1. finds a device
 2. registers the block device
 3. request_module(default iosched)
					4. modprobe in userland
					5. load and init module
					6. async_synchronize_full()

Async A waits for modprobe to finish in request_module() and modprobe
waits for async A to finish in async_synchronize_full().

Because there's no easy to track dependency once control goes out to
userland, implementing properly nested flushing is difficult.  For
now, make module init perform async_synchronize_full() iff module init
has queued async jobs as suggested by Linus.

This avoids the described deadlock because iosched module doesn't use
async and thus wouldn't invoke async_synchronize_full().  This is
hacky and incomplete.  It will deadlock if async module loading nests;
however, this works around the known problem case and seems to be the
best of bad options.

For more details, please refer to the following thread.

  http://thread.gmane.org/gmane.linux.kernel/1420814Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NAlex Riesen <raa.lkml@gmail.com>
Tested-by: NMing Lei <ming.lei@canonical.com>
Tested-by: NAlex Riesen <raa.lkml@gmail.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 0fb9656d "tracing: Make tracing_enabled be equal to tracing_on"
changes the behaviour of trace_pipe, ie. it makes trace_pipe return if
we've read something and tracing is enabled, and this means that we have
to 'cat trace_pipe' again and again while running tests.

IMO the right way is if tracing is enabled, we always block and wait for
ring buffer, or we may lose what we want since ring buffer's size is limited.

Link: http://lkml.kernel.org/r/1358132051-5410-1-git-send-email-bo.li.liu@oracle.comSigned-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Prarit's excellent bug report:
> In recent Fedora releases (F17 & F18) some users have reported seeing
> messages similar to
>
> [   15.478160] kvm: Could not allocate 304 bytes percpu data
> [   15.478174] PERCPU: allocation failed, size=304 align=32, alloc from
> reserved chunk failed
>
> during system boot.  In some cases, users have also reported seeing this
> message along with a failed load of other modules.
>
> What is happening is systemd is loading an instance of the kvm module for
> each cpu found (see commit e9bda3b3).  When the module load occurs the kernel
> currently allocates the modules percpu data area prior to checking to see
> if the module is already loaded or is in the process of being loaded.  If
> the module is already loaded, or finishes load, the module loading code
> releases the current instance's module's percpu data.

Now we have a new state MODULE_STATE_UNFORMED, we can insert the
module into the list (and thus guarantee its uniqueness) before we
allocate the per-cpu region.
Reported-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Tested-by: NPrarit Bhargava <prarit@redhat.com>

You should never look at such a module, so it's excised from all paths
which traverse the modules list.

We add the state at the end, to avoid gratuitous ABI break (ksplice).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

audit_log_start() performs the same jiffies comparison in two places.
If sufficient time has elapsed between the two comparisons, the second
one produces a negative sleep duration:

  schedule_timeout: wrong timeout value fffffffffffffff0
  Pid: 6606, comm: trinity-child1 Not tainted 3.8.0-rc1+ #43
  Call Trace:
    schedule_timeout+0x305/0x340
    audit_log_start+0x311/0x470
    audit_log_exit+0x4b/0xfb0
    __audit_syscall_exit+0x25f/0x2c0
    sysret_audit+0x17/0x21

Fix it by performing the comparison a single time.
Reported-by: NDave Jones <davej@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's possible for audit_log_start() to return NULL.  Handle it in the
various callers.
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Julien Tinnes <jln@google.com>
Cc: Will Drewry <wad@google.com>
Cc: Steve Grubb <sgrubb@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The seccomp path was using AUDIT_ANOM_ABEND from when seccomp mode 1
could only kill a process.  While we still want to make sure an audit
record is forced on a kill, this should use a separate record type since
seccomp mode 2 introduces other behaviors.

In the case of "handled" behaviors (process wasn't killed), only emit a
record if the process is under inspection.  This change also fixes
userspace examination of seccomp audit events, since it was considered
malformed due to missing fields of the AUDIT_ANOM_ABEND event type.
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Julien Tinnes <jln@google.com>
Acked-by: NWill Drewry <wad@chromium.org>
Acked-by: NSteve Grubb <sgrubb@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

down_write_nest_lock() provides a means to annotate locking scenario
where an outer lock is guaranteed to serialize the order nested locks
are being acquired.

This is analogoue to already existing mutex_lock_nest_lock() and
spin_lock_nest_lock().
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mel@csn.ul.ie>
Tested-by: NSedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 02404baf "tracing: Remove deprecated tracing_enabled file"
removed the tracing_enabled file as it never worked properly and
the tracing_on file should be used instead. But the tracing_on file
didn't call into the tracers start/stop routines like the
tracing_enabled file did. This caused trace-cmd to break when it
enabled the irqsoff tracer.

If you just did "echo irqsoff > current_tracer" then it would work
properly. But the tool trace-cmd disables tracing first by writing
"0" into the tracing_on file. Then it writes "irqsoff" into
current_tracer and then writes "1" into tracing_on. Unfortunately,
the above commit changed the irqsoff tracer to check the tracing_on
status instead of the tracing_enabled status. If it's disabled then
it does not start the tracer internals.

The problem is that writing "1" into tracing_on does not call the
tracers "start" routine like writing "1" into tracing_enabled did.
This makes the irqsoff tracer not start when using the trace-cmd
tool, and is a regression for userspace.

Simple fix is to have the tracing_on file call the tracers start()
method when being enabled (and the stop() method when disabled).
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Fix new kernel-doc warning in auditfilter.c:

  Warning(kernel/auditfilter.c:1157): Excess function parameter 'uid' description in 'audit_receive_filter'
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: linux-audit@redhat.com (subscribers-only)
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The latest change to allow trace options to be set on the command
line also broke the trace_options file.

The zeroing of the last byte of the option name that is echoed into
the trace_option file was removed with the consolidation of some
of the code. The compare between the option and what was written to
the trace_options file fails because the string holding the data
written doesn't terminate with a null character.

A zero needs to be added to the end of the string copied from
user space.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

This commit adds event tracing for callback acceleration to allow better
tracking of callbacks through the system.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Currently, callbacks are advanced each time the corresponding CPU
notices a change in its leaf rcu_node structure's ->completed value
(this value counts grace-period completions).  This approach has worked
quite well, but with the advent of RCU_FAST_NO_HZ, we cannot count on
a given CPU seeing all the grace-period completions.  When a CPU misses
a grace-period completion that occurs while it is in dyntick-idle mode,
this will delay invocation of its callbacks.

In addition, acceleration of callbacks (when RCU realizes that a given
callback need only wait until the end of the next grace period, rather
than having to wait for a partial grace period followed by a full
grace period) must be carried out extremely carefully.  Insufficient
acceleration will result in unnecessarily long grace-period latencies,
while excessive acceleration will result in premature callback invocation.
Changes that involve this tradeoff are therefore among the most
nerve-wracking changes to RCU.

This commit therefore explicitly tags groups of callbacks with the
number of the grace period that they are waiting for.  This means that
callback-advancement and callback-acceleration functions are idempotent,
so that excessive acceleration will merely waste a few CPU cycles.  This
also allows a CPU to take full advantage of any grace periods that have
elapsed while it has been in dyntick-idle mode.  It should also enable
simulataneous simplifications to and optimizations of RCU_FAST_NO_HZ.
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>