releases/3.0.57/acpi-pnp-do-not-crash-due-to-stale-pointer-use-during-system-resume.patch

   1 From a6b5e88c0e42093b9057856f35770966c8c591e3 Mon Sep 17 00:00:00 2001
   2 From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
   3 Date: Fri, 30 Nov 2012 13:05:05 +0100
   4 Subject: ACPI / PNP: Do not crash due to stale pointer use during system resume
   5
   6 From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
   7
   8 commit a6b5e88c0e42093b9057856f35770966c8c591e3 upstream.
   9
  10 During resume from system suspend the 'data' field of
  11 struct pnp_dev in pnpacpi_set_resources() may be a stale pointer,
  12 due to removal of the associated ACPI device node object in the
  13 previous suspend-resume cycle.  This happens, for example, if a
  14 dockable machine is booted in the docking station and then suspended
  15 and resumed and suspended again.  If that happens,
  16 pnpacpi_build_resource_template() called from pnpacpi_set_resources()
  17 attempts to use that pointer and crashes.
  18
  19 However, pnpacpi_set_resources() actually checks the device's ACPI
  20 handle, attempts to find the ACPI device node object attached to it
  21 and returns an error code if that fails, so in fact it knows what the
  22 correct value of dev->data should be.  Use this observation to update
  23 dev->data with the correct value if necessary and dump a call trace
  24 if that's the case (once).
  25
  26 We still need to fix the root cause of this issue, but preventing
  27 systems from crashing because of it is an improvement too.
  28
  29 Reported-and-tested-by: Zdenek Kabelac <zdenek.kabelac@gmail.com>
  30 References: https://bugzilla.kernel.org/show_bug.cgi?id=51071
  31 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  32 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  33
  34 ---
  35  drivers/pnp/pnpacpi/core.c |    3 +++
  36  1 file changed, 3 insertions(+)
  37
  38 --- a/drivers/pnp/pnpacpi/core.c
  39 +++ b/drivers/pnp/pnpacpi/core.c
  40 @@ -94,6 +94,9 @@ static int pnpacpi_set_resources(struct
  41                 return -ENODEV;
  42         }
  43
  44 +       if (WARN_ON_ONCE(acpi_dev != dev->data))
  45 +               dev->data = acpi_dev;
  46 +
  47         ret = pnpacpi_build_resource_template(dev, &buffer);
  48         if (ret)
  49                 return ret;