linux-stable.git/include/linux, branch v3.1.5

firmware: Sigma: Fix endianess issues

2011-12-09T16:54:34+00:00

commit bda63586bc5929e97288cdb371bb6456504867ed upstream.

Currently the SigmaDSP firmware loader only works correctly on little-endian
systems. Fix this by using the proper endianess conversion functions.

Signed-off-by: Lars-Peter Clausen 
Acked-by: Mike Frysinger 
Signed-off-by: Mark Brown 
Signed-off-by: Greg Kroah-Hartman

firmware: Sigma: Prevent out of bounds memory access

2011-12-09T16:54:34+00:00

commit 4f718a29fe4908c2cea782f751e9805319684e2b upstream.

The SigmaDSP firmware loader currently does not perform enough boundary size
checks when processing the firmware. As a result it is possible that a
malformed firmware can cause an out of bounds memory access.

This patch adds checks which ensure that both the action header and the payload
are completely inside the firmware data boundaries before processing them.

Signed-off-by: Lars-Peter Clausen 
Acked-by: Mike Frysinger 
Signed-off-by: Mark Brown 
Signed-off-by: Greg Kroah-Hartman

clocksource: Avoid selecting mult values that might overflow when adjusted

2011-12-09T16:54:24+00:00

commit d65670a78cdbfae94f20a9e05ec705871d7cdf2b upstream.

For some frequencies, the clocks_calc_mult_shift() function will
unfortunately select mult values very close to 0xffffffff.  This
has the potential to overflow when NTP adjusts the clock, adding
to the mult value.

This patch adds a clocksource.maxadj value, which provides
an approximation of an 11% adjustment(NTP limits adjustments to
500ppm and the tick adjustment is limited to 10%), which could
be made to the clocksource.mult value. This is then used to both
check that the current mult value won't overflow/underflow, as
well as warning us if the timekeeping_adjust() code pushes over
that 11% boundary.

v2: Fix max_adjustment calculation, and improve WARN_ONCE
messages.

v3: Don't warn before maxadj has actually been set

CC: Yong Zhang 
CC: David Daney 
CC: Thomas Gleixner 
CC: Chen Jie 
CC: zhangfx 
Reported-by: Chen Jie 
Reported-by: zhangfx 
Tested-by: Yong Zhang 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

vmscan: fix shrinker callback bug in fs/super.c

2011-11-26T17:08:40+00:00

commit 09f363c7363eb10cfb4b82094bd7064e5608258b upstream.

The callback must not return -1 when nr_to_scan is zero. Fix the bug in
fs/super.c and add this requirement to the callback specification.

Signed-off-by: Mikulas Patocka 
Cc: Dave Chinner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

nfs: when attempting to open a directory, fall back on normal lookup (try #5)

2011-11-26T17:08:36+00:00

commit 1788ea6e3b2a58cf4fb00206e362d9caff8d86a7 upstream.

commit d953126 changed how nfs_atomic_lookup handles an -EISDIR return
from an OPEN call. Prior to that patch, that caused the client to fall
back to doing a normal lookup. When that patch went in, the code began
returning that error to userspace. The d_revalidate codepath however
never had the corresponding change, so it was still possible to end up
with a NULL ctx->state pointer after that.

That patch caused a regression. When we attempt to open a directory that
does not have a cached dentry, that open now errors out with EISDIR. If
you attempt the same open with a cached dentry, it will succeed.

Fix this by reverting the change in nfs_atomic_lookup and allowing
attempts to open directories to fall back to a normal lookup

Also, add a NFSv4-specific f_ops->open routine that just returns
-ENOTDIR. This should never be called if things are working properly,
but if it ever is, then the dprintk may help in debugging.

To facilitate this, a new file_operations field is also added to the
nfs_rpc_ops struct.

Signed-off-by: Jeff Layton 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

thp: share get_huge_page_tail()

2011-11-11T17:44:01+00:00

commit b35a35b556f5e6b7993ad0baf20173e75c09ce8c upstream.

This avoids duplicating the function in every arch gup_fast.

Signed-off-by: Andrea Arcangeli 
Cc: Peter Zijlstra 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Rik van Riel 
Cc: Mel Gorman 
Cc: KOSAKI Motohiro 
Cc: Benjamin Herrenschmidt 
Cc: David Gibson 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: David Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ext2,ext3,ext4: don't inherit APPEND_FL or IMMUTABLE_FL for new inodes

2011-11-11T17:43:50+00:00

commit 1cd9f0976aa4606db8d6e3dc3edd0aca8019372a upstream.

This doesn't make much sense, and it exposes a bug in the kernel where
attempts to create a new file in an append-only directory using
O_CREAT will fail (but still leave a zero-length file).  This was
discovered when xfstests #79 was generalized so it could run on all
file systems.

Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

mm: thp: tail page refcounting fix

2011-11-11T17:43:41+00:00

commit 70b50f94f1644e2aa7cb374819cfd93f3c28d725 upstream.

Michel while working on the working set estimation code, noticed that
calling get_page_unless_zero() on a random pfn_to_page(random_pfn)
wasn't safe, if the pfn ended up being a tail page of a transparent
hugepage under splitting by __split_huge_page_refcount().

He then found the problem could also theoretically materialize with
page_cache_get_speculative() during the speculative radix tree lookups
that uses get_page_unless_zero() in SMP if the radix tree page is freed
and reallocated and get_user_pages is called on it before
page_cache_get_speculative has a chance to call get_page_unless_zero().

So the best way to fix the problem is to keep page_tail->_count zero at
all times.  This will guarantee that get_page_unless_zero() can never
succeed on any tail page.  page_tail->_mapcount is guaranteed zero and
is unused for all tail pages of a compound page, so we can simply
account the tail page references there and transfer them to
tail_page->_count in __split_huge_page_refcount() (in addition to the
head_page->_mapcount).

While debugging this s/_count/_mapcount/ change I also noticed get_page is
called by direct-io.c on pages returned by get_user_pages.  That wasn't
entirely safe because the two atomic_inc in get_page weren't atomic.  As
opposed to other get_user_page users like secondary-MMU page fault to
establish the shadow pagetables would never call any superflous get_page
after get_user_page returns.  It's safer to make get_page universally safe
for tail pages and to use get_page_foll() within follow_page (inside
get_user_pages()).  get_page_foll() is safe to do the refcounting for tail
pages without taking any locks because it is run within PT lock protected
critical sections (PT lock for pte and page_table_lock for
pmd_trans_huge).

The standard get_page() as invoked by direct-io instead will now take
the compound_lock but still only for tail pages.  The direct-io paths
are usually I/O bound and the compound_lock is per THP so very
finegrined, so there's no risk of scalability issues with it.  A simple
direct-io benchmarks with all lockdep prove locking and spinlock
debugging infrastructure enabled shows identical performance and no
overhead.  So it's worth it.  Ideally direct-io should stop calling
get_page() on pages returned by get_user_pages().  The spinlock in
get_page() is already optimized away for no-THP builds but doing
get_page() on tail pages returned by GUP is generally a rare operation
and usually only run in I/O paths.

This new refcounting on page_tail->_mapcount in addition to avoiding new
RCU critical sections will also allow the working set estimation code to
work without any further complexity associated to the tail page
refcounting with THP.

Signed-off-by: Andrea Arcangeli 
Reported-by: Michel Lespinasse 
Reviewed-by: Michel Lespinasse 
Reviewed-by: Minchan Kim 
Cc: Peter Zijlstra 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Rik van Riel 
Cc: Mel Gorman 
Cc: KOSAKI Motohiro 
Cc: Benjamin Herrenschmidt 
Cc: David Gibson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

readlinkat: ensure we return ENOENT for the empty pathname for normal lookups

2011-11-11T17:43:35+00:00

commit 1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8 upstream.

Since the commit below which added O_PATH support to the *at() calls, the
error return for readlink/readlinkat for the empty pathname has switched
from ENOENT to EINVAL:

  commit 65cfc6722361570bfe255698d9cd4dccaf47570d
  Author: Al Viro 
  Date:   Sun Mar 13 15:56:26 2011 -0400

    readlinkat(), fchownat() and fstatat() with empty relative pathnames

This is both unexpected for userspace and makes readlink/readlinkat
inconsistant with all other interfaces; and inconsistant with our stated
return for these pathnames.

As the readlinkat call does not have a flags parameter we cannot use the
AT_EMPTY_PATH approach used in the other calls.  Therefore expose whether
the original path is infact entry via a new user_path_at_empty() path
lookup function.  Use this to determine whether to default to EINVAL or
ENOENT for failures.

Addresses http://bugs.launchpad.net/bugs/817187

[akpm@linux-foundation.org: remove unused getname_flags()]
Signed-off-by: Andy Whitcroft 
Cc: Christoph Hellwig 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Greg Kroah-Hartman

mm: avoid null pointer access in vm_struct via /proc/vmallocinfo

2011-11-11T17:43:33+00:00

commit f5252e009d5b87071a919221e4f6624184005368 upstream.

The /proc/vmallocinfo shows information about vmalloc allocations in
vmlist that is a linklist of vm_struct.  It, however, may access pages
field of vm_struct where a page was not allocated.  This results in a null
pointer access and leads to a kernel panic.

Why this happens: In __vmalloc_node_range() called from vmalloc(), newly
allocated vm_struct is added to vmlist at __get_vm_area_node() and then,
some fields of vm_struct such as nr_pages and pages are set at
__vmalloc_area_node().  In other words, it is added to vmlist before it is
fully initialized.  At the same time, when the /proc/vmallocinfo is read,
it accesses the pages field of vm_struct according to the nr_pages field
at show_numa_info().  Thus, a null pointer access happens.

The patch adds the newly allocated vm_struct to the vmlist *after* it is
fully initialized.  So, it can avoid accessing the pages field with
unallocated page when show_numa_info() is called.

Signed-off-by: Mitsuo Hayasaka 
Cc: Andrew Morton 
Cc: David Rientjes 
Cc: Namhyung Kim 
Cc: "Paul E. McKenney" 
Cc: Jeremy Fitzhardinge 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman