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  1. 30 Sep, 2015 15 commits
  3. 29 Sep, 2015 21 commits
  5. 28 Sep, 2015 4 commits
    • Grant Likely's avatar
      drivercore: Fix unregistration path of platform devices · 9965eafe
      Grant Likely authored 
      commit 7f5dcaf1 upstream.

The unregister path of platform_device is broken. On registration, it
will register all resources with either a parent already set, or
type==IORESOURCE_{IO,MEM}. However, on unregister it will release
everything with type==IORESOURCE_{IO,MEM}, but ignore the others. There
are also cases where resources don't get registered in the first place,
like with devices created by of_platform_populate()*.

Fix the unregister path to be symmetrical with the register path by
checking the parent pointer instead of the type field to decide which
resources to unregister. This is safe because the upshot of the
registration path algorithm is that registered resources have a parent
pointer, and non-registered resources do not.

* It can be argued that of_platform_populate() should be registering
  it's resources, and they argument has some merit. However, there are
  quite a few platforms that end up broken if we try to do that due to
  overlapping resources in the device tree. Until that is fixed, we need
  to solve the immediate problem.

Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
Tested-by: default avatarRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Tested-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      9965eafe
    • David Daney's avatar
      of/address: Don't loop forever in of_find_matching_node_by_address(). · ea95c941
      David Daney authored 
      commit 3a496b00 upstream.

If the internal call to of_address_to_resource() fails, we end up
looping forever in of_find_matching_node_by_address().  This can be
caused by a defective device tree, or calling with an incorrect
matches argument.

Fix by calling of_find_matching_node() unconditionally at the end of
the loop.
Signed-off-by: default avatarDavid Daney <david.daney@cavium.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      ea95c941
    • Adrien Schildknecht's avatar
      rtlwifi: rtl8192cu: Add new device ID · 334cf11f
      Adrien Schildknecht authored 
      commit 1642d09f upstream.

The v2 of NetGear WNA1000M uses a different idProduct: USB ID 0846:9043
Signed-off-by: default avatarAdrien Schildknecht <adrien+dev@schischi.me>
Acked-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: default avatarKalle Valo <kvalo@codeaurora.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      334cf11f
    • Jan H. Schönherr's avatar
      sched: Fix cpu_active_mask/cpu_online_mask race · 9ecde004
      Jan H. Schönherr authored 
      commit dd9d3843 upstream.

There is a race condition in SMP bootup code, which may result
in

    WARNING: CPU: 0 PID: 1 at kernel/workqueue.c:4418
    workqueue_cpu_up_callback()
or
    kernel BUG at kernel/smpboot.c:135!

It can be triggered with a bit of luck in Linux guests running
on busy hosts.

	CPU0                        CPUn
	====                        ====

	_cpu_up()
	  __cpu_up()
				    start_secondary()
				      set_cpu_online()
					cpumask_set_cpu(cpu,
						   to_cpumask(cpu_online_bits));
	  cpu_notify(CPU_ONLINE)
	    <do stuff, see below>
					cpumask_set_cpu(cpu,
						   to_cpumask(cpu_active_bits));

During the various CPU_ONLINE callbacks CPUn is online but not
active. Several things can go wrong at that point, depending on
the scheduling of tasks on CPU0.

Variant 1:

  cpu_notify(CPU_ONLINE)
    workqueue_cpu_up_callback()
      rebind_workers()
        set_cpus_allowed_ptr()

  This call fails because it requires an active CPU; rebind_workers()
  ends with a warning:

    WARNING: CPU: 0 PID: 1 at kernel/workqueue.c:4418
    workqueue_cpu_up_callback()

Variant 2:

  cpu_notify(CPU_ONLINE)
    smpboot_thread_call()
      smpboot_unpark_threads()
       ..
        __kthread_unpark()
          __kthread_bind()
          wake_up_state()
           ..
            select_task_rq()
              select_fallback_rq()

  The ->wake_cpu of the unparked thread is not allowed, making a call
  to select_fallback_rq() necessary. Then, select_fallback_rq() cannot
  find an allowed, active CPU and promptly resets the allowed CPUs, so
  that the task in question ends up on CPU0.

  When those unparked tasks are eventually executed, they run
  immediately into a BUG:

    kernel BUG at kernel/smpboot.c:135!

Just changing the order in which the online/active bits are set
(and adding some memory barriers), would solve the two issues
above. However, it would change the order of operations back to
the one before commit 6acbfb96 ("sched: Fix hotplug vs.
set_cpus_allowed_ptr()"), thus, reintroducing that particular
problem.

Going further back into history, we have at least the following
commits touching this topic:
- commit 2baab4e9 ("sched: Fix select_fallback_rq() vs cpu_active/cpu_online")
- commit 5fbd036b ("sched: Cleanup cpu_active madness")

Together, these give us the following non-working solutions:

  - secondary CPU sets active before online, because active is assumed to
    be a subset of online;

  - secondary CPU sets online before active, because the primary CPU
    assumes that an online CPU is also active;

  - secondary CPU sets online and waits for primary CPU to set active,
    because it might deadlock.

Commit 875ebe94 ("powerpc/smp: Wait until secondaries are
active & online") introduces an arch-specific solution to this
arch-independent problem.

Now, go for a more general solution without explicit waiting and
simply set active twice: once on the secondary CPU after online
was set and once on the primary CPU after online was seen.

set_cpus_allowed_ptr()")
Signed-off-by: default avatarJan H. Schönherr <jschoenh@amazon.de>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Anton Blanchard <anton@samba.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Wilson <msw@amazon.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 6acbfb96 ("sched: Fix hotplug vs. set_cpus_allowed_ptr()")
Link: http://lkml.kernel.org/r/1439408156-18840-1-git-send-email-jschoenh@amazon.deSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      9ecde004
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