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  1. 09 Oct, 2014 31 commits
  3. 08 Oct, 2014 9 commits
    • Al Viro's avatar
      be careful with nd->inode in path_init() and follow_dotdot_rcu() · 6e3747f1
      Al Viro authored 
      commit 4023bfc9 upstream.

in the former we simply check if dentry is still valid after picking
its ->d_inode; in the latter we fetch ->d_inode in the same places
where we fetch dentry and its ->d_seq, under the same checks.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      6e3747f1
    • Al Viro's avatar
      don't bugger nd->seq on set_root_rcu() from follow_dotdot_rcu() · 1efec2a1
      Al Viro authored 
      commit 7bd88377 upstream.

return the value instead, and have path_init() do the assignment.  Broken by
"vfs: Fix absolute RCU path walk failures due to uninitialized seq number",
which was Cc-stable with 2.6.38+ as destination.  This one should go where
it went.

To avoid dummy value returned in case when root is already set (it would do
no harm, actually, since the only caller that doesn't ignore the return value
is guaranteed to have nd->root *not* set, but it's more obvious that way),
lift the check into callers.  And do the same to set_root(), to keep them
in sync.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      1efec2a1
    • Guy Martin's avatar
      parisc: Implement new LWS CAS supporting 64 bit operations. · a28866ec
      Guy Martin authored 
      commit 89206491 upstream.

The current LWS cas only works correctly for 32bit. The new LWS allows
for CAS operations of variable size.
Signed-off-by: default avatarGuy Martin <gmsoft@tuxicoman.be>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      a28866ec
    • Richard Larocque's avatar
      alarmtimer: Lock k_itimer during timer callback · addc3fff
      Richard Larocque authored 
      commit 474e941b upstream.

Locks the k_itimer's it_lock member when handling the alarm timer's
expiry callback.

The regular posix timers defined in posix-timers.c have this lock held
during timout processing because their callbacks are routed through
posix_timer_fn().  The alarm timers follow a different path, so they
ought to grab the lock somewhere else.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: default avatarRichard Larocque <rlarocque@google.com>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      addc3fff
    • Richard Larocque's avatar
      alarmtimer: Do not signal SIGEV_NONE timers · 768e06ae
      Richard Larocque authored 
      commit 265b81d2 upstream.

Avoids sending a signal to alarm timers created with sigev_notify set to
SIGEV_NONE by checking for that special case in the timeout callback.

The regular posix timers avoid sending signals to SIGEV_NONE timers by
not scheduling any callbacks for them in the first place.  Although it
would be possible to do something similar for alarm timers, it's simpler
to handle this as a special case in the timeout.

Prior to this patch, the alarm timer would ignore the sigev_notify value
and try to deliver signals to the process anyway.  Even worse, the
sanity check for the value of sigev_signo is skipped when SIGEV_NONE was
specified, so the signal number could be bogus.  If sigev_signo was an
unitialized value (as it often would be if SIGEV_NONE is used), then
it's hard to predict which signal will be sent.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: default avatarRichard Larocque <rlarocque@google.com>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      768e06ae
    • Richard Larocque's avatar
      alarmtimer: Return relative times in timer_gettime · 99bc8f4e
      Richard Larocque authored 
      commit e86fea76 upstream.

Returns the time remaining for an alarm timer, rather than the time at
which it is scheduled to expire.  If the timer has already expired or it
is not currently scheduled, the it_value's members are set to zero.

This new behavior matches that of the other posix-timers and the POSIX
specifications.

This is a change in user-visible behavior, and may break existing
applications.  Hopefully, few users rely on the old incorrect behavior.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: default avatarRichard Larocque <rlarocque@google.com>
[jstultz: minor style tweak]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      99bc8f4e
    • Andrew Hunter's avatar
      jiffies: Fix timeval conversion to jiffies · d7c27452
      Andrew Hunter authored 
      commit d78c9300 upstream.

timeval_to_jiffies tried to round a timeval up to an integral number
of jiffies, but the logic for doing so was incorrect: intervals
corresponding to exactly N jiffies would become N+1. This manifested
itself particularly repeatedly stopping/starting an itimer:

setitimer(ITIMER_PROF, &val, NULL);
setitimer(ITIMER_PROF, NULL, &val);

would add a full tick to val, _even if it was exactly representable in
terms of jiffies_ (say, the result of a previous rounding.)  Doing
this repeatedly would cause unbounded growth in val.  So fix the math.

Here's what was wrong with the conversion: we essentially computed
(eliding seconds)

jiffies = usec  * (NSEC_PER_USEC/TICK_NSEC)

by using scaling arithmetic, which took the best approximation of
NSEC_PER_USEC/TICK_NSEC with denominator of 2^USEC_JIFFIE_SC =
x/(2^USEC_JIFFIE_SC), and computed:

jiffies = (usec * x) >> USEC_JIFFIE_SC

and rounded this calculation up in the intermediate form (since we
can't necessarily exactly represent TICK_NSEC in usec.) But the
scaling arithmetic is a (very slight) *over*approximation of the true
value; that is, instead of dividing by (1 usec/ 1 jiffie), we
effectively divided by (1 usec/1 jiffie)-epsilon (rounding
down). This would normally be fine, but we want to round timeouts up,
and we did so by adding 2^USEC_JIFFIE_SC - 1 before the shift; this
would be fine if our division was exact, but dividing this by the
slightly smaller factor was equivalent to adding just _over_ 1 to the
final result (instead of just _under_ 1, as desired.)

In particular, with HZ=1000, we consistently computed that 10000 usec
was 11 jiffies; the same was true for any exact multiple of
TICK_NSEC.

We could possibly still round in the intermediate form, adding
something less than 2^USEC_JIFFIE_SC - 1, but easier still is to
convert usec->nsec, round in nanoseconds, and then convert using
time*spec*_to_jiffies.  This adds one constant multiplication, and is
not observably slower in microbenchmarks on recent x86 hardware.

Tested: the following program:

int main() {
  struct itimerval zero = {{0, 0}, {0, 0}};
  /* Initially set to 10 ms. */
  struct itimerval initial = zero;
  initial.it_interval.tv_usec = 10000;
  setitimer(ITIMER_PROF, &initial, NULL);
  /* Save and restore several times. */
  for (size_t i = 0; i < 10; ++i) {
    struct itimerval prev;
    setitimer(ITIMER_PROF, &zero, &prev);
    /* on old kernels, this goes up by TICK_USEC every iteration */
    printf("previous value: %ld %ld %ld %ld\n",
           prev.it_interval.tv_sec, prev.it_interval.tv_usec,
           prev.it_value.tv_sec, prev.it_value.tv_usec);
    setitimer(ITIMER_PROF, &prev, NULL);
  }
    return 0;
}

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Turner <pjt@google.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Reviewed-by: default avatarPaul Turner <pjt@google.com>
Reported-by: default avatarAaron Jacobs <jacobsa@google.com>
Signed-off-by: default avatarAndrew Hunter <ahh@google.com>
[jstultz: Tweaked to apply to 3.17-rc]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
[ kamal: backport to 3.13-stable: kernel/time.c ]
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      d7c27452
    • Thomas Gleixner's avatar
      futex: Unlock hb->lock in futex_wait_requeue_pi() error path · 39aaf94d
      Thomas Gleixner authored 
      commit 13c42c2f upstream.

futex_wait_requeue_pi() calls futex_wait_setup(). If
futex_wait_setup() succeeds it returns with hb->lock held and
preemption disabled. Now the sanity check after this does:

        if (match_futex(&q.key, &key2)) {
	   	ret = -EINVAL;
		goto out_put_keys;
	}

which releases the keys but does not release hb->lock.

So we happily return to user space with hb->lock held and therefor
preemption disabled.

Unlock hb->lock before taking the exit route.
Reported-by: default avatarDave "Trinity" Jones <davej@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarDarren Hart <dvhart@linux.intel.com>
Reviewed-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409112318500.4178@nanosSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
[ kamal: backport to 3.13-stable: queue_unlock() args ]
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      39aaf94d
    • Y.C. Chen's avatar
      drm/ast: AST2000 cannot be detected correctly · 765709bf
      Y.C. Chen authored 
      commit 83502a5d upstream.

Type error and cause AST2000 cannot be detected correctly
Signed-off-by: default avatarY.C. Chen <yc_chen@aspeedtech.com>
Reviewed-by: default avatarEgbert Eich <eich@suse.de>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      765709bf
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