linux-stable.git/kernel, branch v3.0.69

ftrace: Update the kconfig for DYNAMIC_FTRACE

2013-03-14T18:32:06+00:00

commit db05021d49a994ee40a9735d9c3cb0060c9babb8 upstream.

The prompt to enable DYNAMIC_FTRACE (the ability to nop and
enable function tracing at run time) had a confusing statement:

 "enable/disable ftrace tracepoints dynamically"

This was written before tracepoints were added to the kernel,
but now that tracepoints have been added, this is very confusing
and has confused people enough to give wrong information during
presentations.

Not only that, I looked at the help text, and it still references
that dreaded daemon that use to wake up once a second to update
the nop locations and brick NICs, that hasn't been around for over
five years.

Time to bring the text up to the current decade.

Reported-by: Ezequiel Garcia 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

cgroup: fix exit() vs rmdir() race

2013-03-03T22:09:07+00:00

commit 71b5707e119653039e6e95213f00479668c79b75 upstream.

In cgroup_exit() put_css_set_taskexit() is called without any lock,
which might lead to accessing a freed cgroup:

thread1                           thread2
---------------------------------------------
exit()
  cgroup_exit()
    put_css_set_taskexit()
      atomic_dec(cgrp->count);
                                   rmdir();
      /* not safe !! */
      check_for_release(cgrp);

rcu_read_lock() can be used to make sure the cgroup is alive.

Signed-off-by: Li Zefan 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

cpuset: fix cpuset_print_task_mems_allowed() vs rename() race

2013-03-03T22:09:06+00:00

commit 63f43f55c9bbc14f76b582644019b8a07dc8219a upstream.

rename() will change dentry->d_name. The result of this race can
be worse than seeing partially rewritten name, but we might access
a stale pointer because rename() will re-allocate memory to hold
a longer name.

It's safe in the protection of dentry->d_lock.

v2: check NULL dentry before acquiring dentry lock.

Signed-off-by: Li Zefan 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

wake_up_process() should be never used to wakeup a TASK_STOPPED/TRACED task

2013-03-03T22:09:06+00:00

Upstream commit 9067ac85d533651b98c2ff903182a20cbb361fcb.

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: Oleg Nesterov 
Signed-off-by: Linus Torvalds 
Cc: Michal Hocko 
Signed-off-by: Greg Kroah-Hartman

ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL

2013-03-03T22:09:06+00:00

Upstream commit 9899d11f654474d2d54ea52ceaa2a1f4db3abd68.

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: Salman Qazi 
Reported-by: Suleiman Souhlal 
Suggested-by: Linus Torvalds 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Linus Torvalds 
Signed-off-by: Michal Hocko 
Signed-off-by: Greg Kroah-Hartman

ptrace: introduce signal_wake_up_state() and ptrace_signal_wake_up()

2013-03-03T22:09:05+00:00

Upstream commit 910ffdb18a6408e14febbb6e4b6840fd2c928c82.

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: Oleg Nesterov 
Signed-off-by: Linus Torvalds 
Signed-off-by: Michal Hocko 
Signed-off-by: Greg Kroah-Hartman

sysctl: fix null checking in bin_dn_node_address()

2013-03-03T22:09:04+00:00

commit df1778be1a33edffa51d094eeda87c858ded6560 upstream.

The null check of `strchr() + 1' is broken, which is always non-null,
leading to OOB read.  Instead, check the result of strchr().

Signed-off-by: Xi Wang 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ftrace: Call ftrace cleanup module notifier after all other notifiers

2013-03-03T22:09:03+00:00

commit 8c189ea64eea01ca20d102ddb74d6936dd16c579 upstream.

Commit: c1bf08ac "ftrace: Be first to run code modification on modules"

changed ftrace module notifier's priority to INT_MAX in order to
process the ftrace nops before anything else could touch them
(namely kprobes). This was the correct thing to do.

Unfortunately, the ftrace module notifier also contains the ftrace
clean up code. As opposed to the set up code, this code should be
run *after* all the module notifiers have run in case a module is doing
correct clean-up and unregisters its ftrace hooks. Basically, ftrace
needs to do clean up on module removal, as it needs to know about code
being removed so that it doesn't try to modify that code. But after it
removes the module from its records, if a ftrace user tries to remove
a probe, that removal will fail due as the record of that code segment
no longer exists.

Nothing really bad happens if the probe removal is called after ftrace
did the clean up, but the ftrace removal function will return an error.
Correct code (such as kprobes) will produce a WARN_ON() if it fails
to remove the probe. As people get annoyed by frivolous warnings, it's
best to do the ftrace clean up after everything else.

By splitting the ftrace_module_notifier into two notifiers, one that
does the module load setup that is run at high priority, and the other
that is called for module clean up that is run at low priority, the
problem is solved.

Reported-by: Frank Ch. Eigler 
Acked-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

posix-timer: Don't call idr_find() with out-of-range ID

2013-03-03T22:09:03+00:00

commit e182bb38d7db7494fa5dcd82da17fe0dedf60ecf upstream.

When idr_find() was fed a negative ID, it used to look up the ID
ignoring the sign bit before recent ("idr: remove MAX_IDR_MASK and
move left MAX_IDR_* into idr.c") patch. Now a negative ID triggers
a WARN_ON_ONCE().

__lock_timer() feeds timer_id from userland directly to idr_find()
without sanitizing it which can trigger the above malfunctions.  Add a
range check on @timer_id before invoking idr_find() in __lock_timer().

While timer_t is defined as int by all archs at the moment, Andrew
worries that it may be defined as a larger type later on.  Make the
test cover larger integers too so that it at least is guaranteed to
not return the wrong timer.

Note that WARN_ON_ONCE() in idr_find() on id < 0 is transitional
precaution while moving away from ignoring MSB.  Once it's gone we can
remove the guard as long as timer_t isn't larger than int.

Signed-off-by: Tejun Heo 
Reported-by: Sasha Levin 
Cc: Andrew Morton 
Link: http://lkml.kernel.org/r/20130220232412.GL3570@htj.dyndns.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

hrtimer: Prevent hrtimer_enqueue_reprogram race

2013-02-28T14:32:23+00:00

commit b22affe0aef429d657bc6505aacb1c569340ddd2 upstream.

hrtimer_enqueue_reprogram contains a race which could result in
timer.base switch during unlock/lock sequence.

hrtimer_enqueue_reprogram is releasing the lock protecting the timer
base for calling raise_softirq_irqsoff() due to a lock ordering issue
versus rq->lock.

If during that time another CPU calls __hrtimer_start_range_ns() on
the same hrtimer, the timer base might switch, before the current CPU
can lock base->lock again and therefor the unlock_timer_base() call
will unlock the wrong lock.

[ tglx: Added comment and massaged changelog ]

Signed-off-by: Leonid Shatz 
Signed-off-by: Izik Eidus 
Cc: Andrea Arcangeli 
Link: http://lkml.kernel.org/r/1359981217-389-1-git-send-email-izik.eidus@ravellosystems.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman