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  1. 05 4月, 2013 14 次提交
  3. 18 3月, 2013 1 次提交
  5. 16 3月, 2013 1 次提交
  7. 15 3月, 2013 1 次提交
    • P
      list: Fix double fetch of pointer in hlist_entry_safe() · f65846a1
      由 Paul E. McKenney 提交于 
      The current version of hlist_entry_safe() fetches the pointer twice,
once to test for NULL and the other to compute the offset back to the
enclosing structure.  This is OK for normal lock-based use because in
that case, the pointer cannot change.  However, when the pointer is
protected by RCU (as in "rcu_dereference(p)"), then the pointer can
change at any time.  This use case can result in the following sequence
of events:

1.	CPU 0 invokes hlist_entry_safe(), fetches the RCU-protected
	pointer as sees that it is non-NULL.

2.	CPU 1 invokes hlist_del_rcu(), deleting the entry that CPU 0
	just fetched a pointer to.  Because this is the last entry
	in the list, the pointer fetched by CPU 0 is now NULL.

3.	CPU 0 refetches the pointer, obtains NULL, and then gets a
	NULL-pointer crash.

This commit therefore applies gcc's "({ })" statement expression to
create a temporary variable so that the specified pointer is fetched
only once, avoiding the above sequence of events.  Please note that
it is the caller's responsibility to use rcu_dereference() as needed.
This allows RCU-protected uses to work correctly without imposing
any additional overhead on the non-RCU case.

Many thanks to Eric Dumazet for spotting root cause!
Reported-by: NCAI Qian <caiqian@redhat.com>
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NLi Zefan <lizefan@huawei.com>
      f65846a1
  9. 14 3月, 2013 6 次提交
  11. 13 3月, 2013 4 次提交
  13. 12 3月, 2013 4 次提交
  15. 09 3月, 2013 1 次提交
  17. 08 3月, 2013 1 次提交
  19. 06 3月, 2013 1 次提交
    • K
      acpi: Export the acpi_processor_get_performance_info · c705c78c
      由 Konrad Rzeszutek Wilk 提交于 
      The git commit d5aaffa9
(cpufreq: handle cpufreq being disabled for all exported function)
tightens the cpufreq API by returning errors when disable_cpufreq()
had been called.

The problem we are hitting is that the module xen-acpi-processor which
uses the ACPI's functions: acpi_processor_register_performance,
acpi_processor_preregister_performance, and acpi_processor_notify_smm
fails at acpi_processor_register_performance with -22.

Note that earlier during bootup in arch/x86/xen/setup.c there is also
an call to cpufreq's API: disable_cpufreq().

This is b/c we want the Linux kernel to parse the ACPI data, but leave
the cpufreq decisions to the hypervisor.

In v3.9 all the checks that d5aaffa9
added are now hit and the calls to cpufreq_register_notifier will now
fail. This means that acpi_processor_ppc_init ends up printing:

"Warning: Processor Platform Limit not supported"

and the acpi_processor_ppc_status is not set.

The repercussions of that is that the call to
acpi_processor_register_performance fails right away at:

	if (!(acpi_processor_ppc_status & PPC_REGISTERED))

and we don't progress any further on parsing and extracting the _P*
objects.

The only reason the Xen code called that function was b/c it was
exported and the only way to gather the P-states. But we can also
just make acpi_processor_get_performance_info be exported and not
use acpi_processor_register_performance. This patch does so.
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      c705c78c
  21. 05 3月, 2013 1 次提交
    • N
      usb: gadget: composite: fix kernel-doc warnings · 43febb27
      由 Nishanth Menon 提交于 
      A few trivial fixes for composite driver:

Warning(include/linux/usb/composite.h:165): No description found for parameter
	'fs_descriptors'
Warning(include/linux/usb/composite.h:165): Excess struct/union/enum/typedef
	member 'descriptors' description in 'usb_function'
Warning(include/linux/usb/composite.h:321): No description found for parameter
	'gadget_driver'
Warning(drivers/usb/gadget/composite.c:1777): Excess function parameter 'bind'
	description in 'usb_composite_probe'

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NNishanth Menon <nm@ti.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
      43febb27
  23. 04 3月, 2013 4 次提交
    • R
      ACPI / glue: Drop .find_bridge() callback from struct acpi_bus_type · 92414481
      由 Rafael J. Wysocki 提交于 
      After PCI and USB have stopped using the .find_bridge() callback in
struct acpi_bus_type, the only remaining user of it is SATA, but SATA
only pretends to be a user, because it points that callback to a stub
always returning -ENODEV.

For this reason, drop the SATA's dummy .find_bridge() callback and
remove .find_bridge(), which is not used any more, from struct
acpi_bus_type entirely.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Acked-by: NJeff Garzik <jgarzik@pobox.com>
      92414481
    • R
      ACPI / glue: Add .match() callback to struct acpi_bus_type · 53540098
      由 Rafael J. Wysocki 提交于 
      USB uses the .find_bridge() callback from struct acpi_bus_type
incorrectly, because as a result of the way it is used by USB every
device in the system that doesn't have a bus type or parent is
passed to usb_acpi_find_device() for inspection.

What USB actually needs, though, is to call usb_acpi_find_device()
for USB ports that don't have a bus type defined, but have
usb_port_device_type as their device type, as well as for USB
devices.

To fix that replace the struct bus_type pointer in struct
acpi_bus_type used for matching devices to specific subsystems
with a .match() callback to be used for this purpose and update
the users of struct acpi_bus_type, including USB, accordingly.
Define the .match() callback routine for USB, usb_acpi_bus_match(),
in such a way that it will cover both USB devices and USB ports
and remove the now redundant .find_bridge() callback pointer from
usb_acpi_bus.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Acked-by: NJeff Garzik <jgarzik@pobox.com>
      53540098
    • K
      eCryptfs: allow userspace messaging to be disabled · 290502be
      由 Kees Cook 提交于 
      When the userspace messaging (for the less common case of userspace key
wrap/unwrap via ecryptfsd) is not needed, allow eCryptfs to build with
it removed. This saves on kernel code size and reduces potential attack
surface by removing the /dev/ecryptfs node.
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
      290502be
    • E
      fs: Limit sys_mount to only request filesystem modules. · 7f78e035
      由 Eric W. Biederman 提交于 
      Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.

A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.

Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.

Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives.  Allowing simple, safe,
well understood work-arounds to known problematic software.

This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work.  While writing this patch I saw a handful of such
cases.  The most significant being autofs that lives in the module
autofs4.

This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.

After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module.  The common pattern in the kernel is to call request_module()
without regards to the users permissions.  In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted.  In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Reported-by: NKees Cook <keescook@google.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      7f78e035
  25. 03 3月, 2013 1 次提交
    • J
      mm: define VM_GROWSUP for CONFIG_METAG · 9ca52ed9
      由 James Hogan 提交于 
      Commit cc2383ec ("mm: introduce
arch-specific vma flag VM_ARCH_1") merged in v3.7-rc1.

The above commit combined several arch-specific vma flags into one, and
in the process it changed the VM_GROWSUP definition to depend on
specific architectures rather than CONFIG_STACK_GROWSUP. Therefore add
an ifdef for CONFIG_METAG to also set VM_GROWSUP.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-mm@kvack.org
      9ca52ed9