+ memcg-res_counter_read_u64-fix-potential-races-on-32-bit-machines.patch added to -mm tree

+ memcg-res_counter_read_u64-fix-potential-races-on-32-bit-machines.patch added to -mm tree

[akpm]

The patch titled
     memcg: res_counter_read_u64(): fix potential races on 32-bit machines
has been added to the -mm tree.  Its filename is
     memcg-res_counter_read_u64-fix-potential-races-on-32-bit-machines.patch

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*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this

The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/

------------------------------------------------------
Subject: memcg: res_counter_read_u64(): fix potential races on 32-bit machines
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

res_counter_read_u64 reads u64 value without lock.  It's dangerous in a
32bit environment.  Add locking.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/res_counter.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff -puN kernel/res_counter.c~memcg-res_counter_read_u64-fix-potential-races-on-32-bit-machines kernel/res_counter.c
--- a/kernel/res_counter.c~memcg-res_counter_read_u64-fix-potential-races-on-32-bit-machines
+++ a/kernel/res_counter.c
@@ -126,10 +126,24 @@ ssize_t res_counter_read(struct res_coun
 			pos, buf, s - buf);
 }
 
+#if BITS_PER_LONG == 32
+u64 res_counter_read_u64(struct res_counter *counter, int member)
+{
+	unsigned long flags;
+	u64 ret;
+
+	spin_lock_irqsave(&counter->lock, flags);
+	ret = *res_counter_member(counter, member);
+	spin_unlock_irqrestore(&counter->lock, flags);
+
+	return ret;
+}
+#else
 u64 res_counter_read_u64(struct res_counter *counter, int member)
 {
 	return *res_counter_member(counter, member);
 }
+#endif
 
 int res_counter_memparse_write_strategy(const char *buf,
 					unsigned long long *res)
_

Patches currently in -mm which might be from kamezawa.hiroyu@jp.fujitsu.com are

origin.patch
memsw-handle-swapaccount-kernel-parameter-correctly.patch
memsw-deprecate-noswapaccount-kernel-parameter-and-schedule-it-for-removal.patch
oom-suppress-nodes-that-are-not-allowed-from-meminfo-on-oom-kill.patch
oom-suppress-show_mem-for-many-nodes-in-irq-context-on-page-alloc-failure.patch
oom-suppress-nodes-that-are-not-allowed-from-meminfo-on-page-alloc-failure.patch
mm-add-replace_page_cache_page-function.patch
memcg-res_counter_read_u64-fix-potential-races-on-32-bit-machines.patch
memcg-fix-ugly-initialization-of-return-value-is-in-caller.patch