Linux 3.0.83

commit 937d4f9ee2fe18a6ab012a343fc3b620756b954e
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Thu Jun 20 11:28:30 2013 -0700

    Linux 3.0.83

commit 088d9d4d782d66941fc9e29ff4eb0dd72f84493b
Author: Sage Weil <sage@inktank.com>
Date:   Fri Feb 22 15:31:00 2013 -0800

    ceph: fix statvfs fr_size

    commit 92a49fb0f79f3300e6e50ddf56238e70678e4202 upstream.

    Different versions of glibc are broken in different ways, but the short of
    it is that for the time being, frsize should == bsize, and be used as the
    multiple for the blocks, free, and available fields.  This mirrors what is
    done for NFS.  The previous reporting of the page size for frsize meant
    that newer glibc and df would report a very small value for the fs size.

    Fixes http://tracker.ceph.com/issues/3793.

    Signed-off-by: Sage Weil <sage@inktank.com>
    Reviewed-by: Greg Farnum <greg@inktank.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 0ffdfdbe55c84906dd65627f069619bec54e5422
Author: Kees Cook <keescook@chromium.org>
Date:   Wed Jun 5 11:47:18 2013 -0700

    x86: Fix typo in kexec register clearing

    commit c8a22d19dd238ede87aa0ac4f7dbea8da039b9c1 upstream.

    Fixes a typo in register clearing code. Thanks to PaX Team for fixing
    this originally, and James Troup for pointing it out.

    Signed-off-by: Kees Cook <keescook@chromium.org>
    Link: http://lkml.kernel.org/r/20130605184718.GA8396@www.outflux.net
    Cc: PaX Team <pageexec@freemail.hu>
    Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 79848ba66d91e0c171ff203363e0c96629279c15
Author: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Date:   Wed Jun 12 14:05:04 2013 -0700

    mm: migration: add migrate_entry_wait_huge()

    commit 30dad30922ccc733cfdbfe232090cf674dc374dc upstream.

    When we have a page fault for the address which is backed by a hugepage
    under migration, the kernel can't wait correctly and do busy looping on
    hugepage fault until the migration finishes.  As a result, users who try
    to kick hugepage migration (via soft offlining, for example) occasionally
    experience long delay or soft lockup.

    This is because pte_offset_map_lock() can't get a correct migration entry
    or a correct page table lock for hugepage.  This patch introduces
    migration_entry_wait_huge() to solve this.

    Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
    Reviewed-by: Rik van Riel <riel@redhat.com>
    Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
    Reviewed-by: Michal Hocko <mhocko@suse.cz>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Andi Kleen <andi@firstfloor.org>
    Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 78ef884ebb6c02d45abefc95350f428be7390a26
Author: Rafael Aquini <aquini@redhat.com>
Date:   Wed Jun 12 14:04:49 2013 -0700

    swap: avoid read_swap_cache_async() race to deadlock while waiting on discard I/O completion

    commit cbab0e4eec299e9059199ebe6daf48730be46d2b upstream.

    read_swap_cache_async() can race against get_swap_page(), and stumble
    across a SWAP_HAS_CACHE entry in the swap map whose page wasn't brought
    into the swapcache yet.

    This transient swap_map state is expected to be transitory, but the
    actual placement of discard at scan_swap_map() inserts a wait for I/O
    completion thus making the thread at read_swap_cache_async() to loop
    around its -EEXIST case, while the other end at get_swap_page() is
    scheduled away at scan_swap_map().  This can leave the system deadlocked
    if the I/O completion happens to be waiting on the CPU waitqueue where
    read_swap_cache_async() is busy looping and !CONFIG_PREEMPT.

    This patch introduces a cond_resched() call to make the aforementioned
    read_swap_cache_async() busy loop condition to bail out when necessary,
    thus avoiding the subtle race window.

    Signed-off-by: Rafael Aquini <aquini@redhat.com>
    Acked-by: Johannes Weiner <hannes@cmpxchg.org>
    Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Acked-by: Hugh Dickins <hughd@google.com>
    Cc: Shaohua Li <shli@kernel.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit bac5719cdfb081dd68b0eeef7d9796c15fc29811
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Mon Jun 10 09:47:58 2013 +0200

    drm/i915: prefer VBT modes for SVDO-LVDS over EDID

    commit c3456fb3e4712d0448592af3c5d644c9472cd3c1 upstream.

    In

    commit 53d3b4d7778daf15900867336c85d3f8dd70600c
    Author: Egbert Eich <eich@suse.de>
    Date:   Tue Jun 4 17:13:21 2013 +0200

        drm/i915/sdvo: Use &intel_sdvo->ddc instead of intel_sdvo->i2c for DDC

    Egbert Eich fixed a long-standing bug where we simply used a
    non-working i2c controller to read the EDID for SDVO-LVDS panels.
    Unfortunately some machines seem to not be able to cope with the mode
    provided in the EDID. Specifically they seem to not be able to cope
    with a 4x pixel mutliplier instead of a 2x one, which seems to have
    been worked around by slightly changing the panels native mode in the
    VBT so that the dotclock is just barely above 50MHz.

    Since it took forever to notice the breakage it's fairly safe to
    assume that at least for SDVO-LVDS panels the VBT contains fairly sane
    data. So just switch around the order and use VBT modes first.

    v2: Also add EDID modes just in case, and spell Egbert correctly.

    v3: Elaborate a bit more about what's going on on Chris' machine.

    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65524
    Reported-and-tested-by: Chris Wilson <chris@chris-wilson.co.uk>
    Cc: Egbert Eich <eich@suse.de>
    Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 319d630e7f0778c8999f6ef503998a4d99cee5f1
Author: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Date:   Sat Jun 1 07:08:09 2013 +0530

    ath9k: Disable PowerSave by default

    commit 531671cb17af07281e6f28c1425f754346e65c41 upstream.

    Almost all the DMA issues which have plagued ath9k (in station mode)
    for years are related to PS. Disabling PS usually "fixes" the user's
    connection stablility. Reports of DMA problems are still trickling in
    and are sitting in the kernel bugzilla. Until the PS code in ath9k is
    given a thorough review, disbale it by default. The slight increase
    in chip power consumption is a small price to pay for improved link
    stability.

    Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
    Signed-off-by: John W. Linville <linville@tuxdriver.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 720083f1dc15ac6b6fb85b323d0eae1a151e20ce
Author: Kees Cook <keescook@chromium.org>
Date:   Fri May 10 14:48:21 2013 -0700

    b43: stop format string leaking into error msgs

    commit e0e29b683d6784ef59bbc914eac85a04b650e63c upstream.

    The module parameter "fwpostfix" is userspace controllable, unfiltered,
    and is used to define the firmware filename. b43_do_request_fw() populates
    ctx->errors[] on error, containing the firmware filename. b43err()
    parses its arguments as a format string. For systems with b43 hardware,
    this could lead to a uid-0 to ring-0 escalation.

    CVE-2013-2852

    Signed-off-by: Kees Cook <keescook@chromium.org>
    Signed-off-by: John W. Linville <linville@tuxdriver.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm, oom: do not emit oom killer warning if chosen thread is already exiting

If a thread is chosen for oom kill and is already PF_EXITING, then the oom
killer simply sets TIF_MEMDIE and returns.  This allows the thread to have
access to memory reserves so that it may quickly exit.  This logic is
preceeded with a comment saying there's no need to alarm the sysadmin.
This patch adds truth to that statement.

There's no need to emit any warning about the oom condition if the thread
is already exiting since it will not be killed.  In this condition, just
silently return the oom killer since its only giving access to memory
reserves and is otherwise a no-op.

Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm, oom: introduce independent oom killer ratelimit state

printk_ratelimit() uses the global ratelimit state for all printks.  The
oom killer should not be subjected to this state just because another
subsystem or driver may be flooding the kernel log.

This patch introduces printk ratelimiting specifically for the oom killer.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm, oom: fold oom_kill_task() into oom_kill_process()

oom_kill_task() has a single caller, so fold it into its parent function,
oom_kill_process().  Slightly reduces the number of lines in the oom
killer.

Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Conflicts:
	mm/oom_kill.c
mm, oom: force oom kill on sysrq+f

The oom killer chooses not to kill a thread if:

 - an eligible thread has already been oom killed and has yet to exit,
   and

 - an eligible thread is exiting but has yet to free all its memory and
   is not the thread attempting to currently allocate memory.

SysRq+F manually invokes the global oom killer to kill a memory-hogging
task.  This is normally done as a last resort to free memory when no
progress is being made or to test the oom killer itself.

For both uses, we always want to kill a thread and never defer.  This
patch causes SysRq+F to always kill an eligible thread and can be used to
force a kill even if another oom killed thread has failed to exit.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Conflicts:
	mm/oom_kill.c
mm, memcg: pass charge order to oom killer

The oom killer typically displays the allocation order at the time of oom
as a part of its diangostic messages (for global, cpuset, and mempolicy
ooms).

The memory controller may also pass the charge order to the oom killer so
it can emit the same information.  This is useful in determining how large
the memory allocation is that triggered the oom killer.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
signal: oom_kill_task: use SEND_SIG_FORCED instead of force_sig()

Change oom_kill_task() to use do_send_sig_info(SEND_SIG_FORCED) instead
of force_sig(SIGKILL).  With the recent changes we do not need force_ to
kill the CLONE_NEWPID tasks.

And this is more correct.  force_sig() can race with the exiting thread
even if oom_kill_task() checks p->mm != NULL, while
do_send_sig_info(group => true) kille the whole process.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
slab, lockdep: Annotate the locks before using them

Fernando found we hit the regular OFF_SLAB 'recursion' before we
annotate the locks, cure this.

The relevant portion of the stack-trace:

> [    0.000000]  [<c085e24f>] rt_spin_lock+0x50/0x56
> [    0.000000]  [<c04fb406>] __cache_free+0x43/0xc3
> [    0.000000]  [<c04fb23f>] kmem_cache_free+0x6c/0xdc
> [    0.000000]  [<c04fb2fe>] slab_destroy+0x4f/0x53
> [    0.000000]  [<c04fb396>] free_block+0x94/0xc1
> [    0.000000]  [<c04fc551>] do_tune_cpucache+0x10b/0x2bb
> [    0.000000]  [<c04fc8dc>] enable_cpucache+0x7b/0xa7
> [    0.000000]  [<c0bd9d3c>] kmem_cache_init_late+0x1f/0x61
> [    0.000000]  [<c0bba687>] start_kernel+0x24c/0x363
> [    0.000000]  [<c0bba0ba>] i386_start_kernel+0xa9/0xaf

Reported-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1311888176.2617.379.camel@laptop
Signed-off-by: Ingo Molnar <mingo@elte.hu>
slab, lockdep: Fix silly bug

Commit 30765b92 ("slab, lockdep: Annotate the locks before using
them") moves the init_lock_keys() call from after g_cpucache_up =
FULL, to before it. And overlooks the fact that init_node_lock_keys()
tests for it and ignores everything !FULL.

Introduce a LATE stage and change the lockdep test to be <LATE.

Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
slab: fix the DEADLOCK issue on l3 alien lock

commit 947ca1856a7e60aa6d20536785e6a42dff25aa6e upstream.

DEADLOCK will be report while running a kernel with NUMA and LOCKDEP enabled,
the process of this fake report is:

	   kmem_cache_free()	//free obj in cachep
	-> cache_free_alien()	//acquire cachep's l3 alien lock
	-> __drain_alien_cache()
	-> free_block()
	-> slab_destroy()
	-> kmem_cache_free()	//free slab in cachep->slabp_cache
	-> cache_free_alien()	//acquire cachep->slabp_cache's l3 alien lock

Since the cachep and cachep->slabp_cache's l3 alien are in the same lock class,
fake report generated.

This should not happen since we already have init_lock_keys() which will
reassign the lock class for both l3 list and l3 alien.

However, init_lock_keys() was invoked at a wrong position which is before we
invoke enable_cpucache() on each cache.

Since until set slab_state to be FULL, we won't invoke enable_cpucache()
on caches to build their l3 alien while creating them, so although we invoked
init_lock_keys(), the l3 alien lock class won't change since we don't have
them until invoked enable_cpucache() later.

This patch will invoke init_lock_keys() after we done enable_cpucache()
instead of before to avoid the fake DEADLOCK report.

Michael traced the problem back to a commit in release 3.0.0:

commit 30765b92ada267c5395fc788623cb15233276f5c
Author: Peter Zijlstra <peterz@infradead.org>
Date:   Thu Jul 28 23:22:56 2011 +0200

    slab, lockdep: Annotate the locks before using them

    Fernando found we hit the regular OFF_SLAB 'recursion' before we
    annotate the locks, cure this.

    The relevant portion of the stack-trace:

    > [    0.000000]  [<c085e24f>] rt_spin_lock+0x50/0x56
    > [    0.000000]  [<c04fb406>] __cache_free+0x43/0xc3
    > [    0.000000]  [<c04fb23f>] kmem_cache_free+0x6c/0xdc
    > [    0.000000]  [<c04fb2fe>] slab_destroy+0x4f/0x53
    > [    0.000000]  [<c04fb396>] free_block+0x94/0xc1
    > [    0.000000]  [<c04fc551>] do_tune_cpucache+0x10b/0x2bb
    > [    0.000000]  [<c04fc8dc>] enable_cpucache+0x7b/0xa7
    > [    0.000000]  [<c0bd9d3c>] kmem_cache_init_late+0x1f/0x61
    > [    0.000000]  [<c0bba687>] start_kernel+0x24c/0x363
    > [    0.000000]  [<c0bba0ba>] i386_start_kernel+0xa9/0xaf

    Reported-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
    Acked-by: Pekka Enberg <penberg@kernel.org>
    Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Link: http://lkml.kernel.org/r/1311888176.2617.379.camel@laptop
    Signed-off-by: Ingo Molnar <mingo@elte.hu>

The commit moved init_lock_keys() before we build up the alien, so we
failed to reclass it.

Acked-by: Christoph Lameter <cl@linux.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
memcg: oom: fix totalpages calculation for memory.swappiness==0

commit 9a5a8f19b43430752067ecaee62fc59e11e88fa6 upstream.

oom_badness() takes a totalpages argument which says how many pages are
available and it uses it as a base for the score calculation.  The value
is calculated by mem_cgroup_get_limit which considers both limit and
total_swap_pages (resp.  memsw portion of it).

This is usually correct but since fe35004fbf9e ("mm: avoid swapping out
with swappiness==0") we do not swap when swappiness is 0 which means
that we cannot really use up all the totalpages pages.  This in turn
confuses oom score calculation if the memcg limit is much smaller than
the available swap because the used memory (capped by the limit) is
negligible comparing to totalpages so the resulting score is too small
if adj!=0 (typically task with CAP_SYS_ADMIN or non zero oom_score_adj).
A wrong process might be selected as result.

The problem can be worked around by checking mem_cgroup_swappiness==0
and not considering swap at all in such a case.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tmpfs: change final i_blocks BUG to WARNING

commit 0f3c42f522dc1ad7e27affc0a4aa8c790bce0a66 upstream.

Under a particular load on one machine, I have hit shmem_evict_inode()'s
BUG_ON(inode->i_blocks), enough times to narrow it down to a particular
race between swapout and eviction.

It comes from the "if (freed > 0)" asymmetry in shmem_recalc_inode(),
and the lack of coherent locking between mapping's nrpages and shmem's
swapped count.  There's a window in shmem_writepage(), between lowering
nrpages in shmem_delete_from_page_cache() and then raising swapped
count, when the freed count appears to be +1 when it should be 0, and
then the asymmetry stops it from being corrected with -1 before hitting
the BUG.

One answer is coherent locking: using tree_lock throughout, without
info->lock; reasonable, but the raw_spin_lock in percpu_counter_add() on
used_blocks makes that messier than expected.  Another answer may be a
further effort to eliminate the weird shmem_recalc_inode() altogether,
but previous attempts at that failed.

So far undecided, but for now change the BUG_ON to WARN_ON: in usual
circumstances it remains a useful consistency check.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmu_notifier_unregister NULL Pointer deref and multiple ->release() callouts

commit 751efd8610d3d7d67b7bdf7f62646edea7365dd7 upstream.

There is a race condition between mmu_notifier_unregister() and
__mmu_notifier_release().

Assume two tasks, one calling mmu_notifier_unregister() as a result of a
filp_close() ->flush() callout (task A), and the other calling
mmu_notifier_release() from an mmput() (task B).

                A                               B
t1                                              srcu_read_lock()
t2              if (!hlist_unhashed())
t3                                              srcu_read_unlock()
t4              srcu_read_lock()
t5                                              hlist_del_init_rcu()
t6                                              synchronize_srcu()
t7              srcu_read_unlock()
t8              hlist_del_rcu()  <--- NULL pointer deref.

Additionally, the list traversal in __mmu_notifier_release() is not
protected by the by the mmu_notifier_mm->hlist_lock which can result in
callouts to the ->release() notifier from both mmu_notifier_unregister()
and __mmu_notifier_release().

-stable suggestions:

The stable trees prior to 3.7.y need commits 21a92735f660 and
70400303ce0c cherry-picked in that order prior to cherry-picking this
commit.  The 3.7.y tree already has those two commits.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Sagi Grimberg <sagig@mellanox.co.il>
Cc: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
	mm/mmu_notifier.c
memcg: fix GPF when cgroup removal races with last exit (partial)

Part of this commit has not been applied.

From the commit description:
When moving tasks from old memcg (with move_charge_at_immigrate on new
memcg), followed by removal of old memcg, hit General Protection Fault in
mem_cgroup_lru_del_list() (called from release_pages called from
free_pages_and_swap_cache from tlb_flush_mmu from tlb_finish_mmu from
exit_mmap from mmput from exit_mm from do_exit).

Somewhat reproducible, takes a few hours: the old struct mem_cgroup has
been freed and poisoned by SLAB_DEBUG, but mem_cgroup_lru_del_list() is
still trying to update its stats, and take page off lru before freeing.

A task, or a charge, or a page on lru: each secures a memcg against
removal.  In this case, the last task has been moved out of the old memcg,
and it is exiting: anonymous pages are uncharged one by one from the
memcg, as they are zapped from its pagetables, so the charge gets down to
0; but the pages themselves are queued in an mmu_gather for freeing.

Most of those pages will be on lru (and force_empty is careful to
lru_add_drain_all, to add pages from pagevec to lru first), but not
necessarily all: perhaps some have been isolated for page reclaim, perhaps
some isolated for other reasons.  So, force_empty may find no task, no
charge and no page on lru, and let the removal proceed.

There would still be no problem if these pages were immediately freed; but
typically (and the put_page_testzero protocol demands it) they have to be
added back to lru before they are found freeable, then removed from lru
and freed.  We don't see the issue when adding, because the
mem_cgroup_iter() loops keep their own reference to the memcg being
scanned; but when it comes to mem_cgroup_lru_del_list().

I believe this was not an issue in v3.2: there, PageCgroupAcctLRU and
PageCgroupUsed flags were used (like a trick with mirrors) to deflect view
of pc->mem_cgroup to the stable root_mem_cgroup when neither set.
38c5d72f3ebe ("memcg: simplify LRU handling by new rule") mercifully
removed those convolutions, but left this General Protection Fault.

But it's surprisingly easy to restore the old behaviour: just check
PageCgroupUsed in mem_cgroup_lru_add_list() (which decides on which lruvec
to add), and reset pc to root_mem_cgroup if page is uncharged.  A risky
change?  just going back to how it worked before; testing, and an audit of
uses of pc->mem_cgroup, show no problem.

And there's a nice bonus: with mem_cgroup_lru_add_list() itself making
sure that an uncharged page goes to root lru, mem_cgroup_reset_owner() no
longer has any purpose, and we can safely revert 4e5f01c2b9b9 ("memcg:
clear pc->mem_cgroup if necessary").

Calling update_page_reclaim_stat() after add_page_to_lru_list() in swap.c
is not strictly necessary: the lru_lock there, with RCU before memcg
structures are freed, makes mem_cgroup_get_reclaim_stat_from_page safe
without that; but it seems cleaner to rely on one dependency less.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: fix oom_kill build errors and warnings
jbd2: use gfp_t instead of int

This silences some Sparse warnings:
fs/jbd2/transaction.c:135:69: warning: incorrect type in argument 2 (different base types)
fs/jbd2/transaction.c:135:69:    expected restricted gfp_t [usertype] flags
fs/jbd2/transaction.c:135:69:    got int [signed] gfp_mask

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
jbd2: fix build when CONFIG_BUG is not enabled

Fix build error when CONFIG_BUG is not enabled:

fs/jbd2/transaction.c:1175:3: error: implicit declaration of function '__WARN'

by changing __WARN() to WARN_ON(), as suggested by
Arnaud Lacombe <lacombar@gmail.com>.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Arnaud Lacombe <lacombar@gmail.com>
jbd2: Unify log messages in jbd2 code

Some jbd2 code prints out kernel messages with "JBD2: " prefix, at the
same time other jbd2 code prints with "JBD: " prefix. Unify the prefix
to "JBD2: ".

Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
treewide: Fix comment and string typo 'bufer'

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Conflicts:
	drivers/media/rc/ene_ir.h
	drivers/net/ethernet/chelsio/cxgb4vf/sge.c
	fs/xfs/xfs_buf.c
jbd2: clear revoked flag on buffers before a new transaction started

Currently, we clear revoked flag only when a block is reused.  However,
this can tigger a false journal error.  Consider a situation when a block
is used as a meta block and is deleted(revoked) in ordered mode, then the
block is allocated as a data block to a file.  At this moment, user changes
the file's journal mode from ordered to journaled and truncates the file.
The block will be considered re-revoked by journal because it has revoked
flag still pending from the last transaction and an assertion triggers.

We fix the problem by keeping the revoked status more uptodate - we clear
revoked flag when switching revoke tables to reflect there is no revoked
buffers in current transaction any more.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>