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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2011-03-23 19:42:18 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-23 22:46:22 -0400
commit6c191cd01a935e5b53ef43c9403c771bb7a32b60 (patch)
tree70c49b4cb52406ea1d8c60f73ad7733f60f9cee9 /kernel
parent61f2e7b0f474225b4226772830ae4b29a3a21f8d (diff)
memcg: res_counter_read_u64(): fix potential races on 32-bit machines
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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/res_counter.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index c7eaa37a768b..34683efa2cce 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -126,10 +126,24 @@ ssize_t res_counter_read(struct res_counter *counter, int member,
126 pos, buf, s - buf); 126 pos, buf, s - buf);
127} 127}
128 128
129#if BITS_PER_LONG == 32
130u64 res_counter_read_u64(struct res_counter *counter, int member)
131{
132 unsigned long flags;
133 u64 ret;
134
135 spin_lock_irqsave(&counter->lock, flags);
136 ret = *res_counter_member(counter, member);
137 spin_unlock_irqrestore(&counter->lock, flags);
138
139 return ret;
140}
141#else
129u64 res_counter_read_u64(struct res_counter *counter, int member) 142u64 res_counter_read_u64(struct res_counter *counter, int member)
130{ 143{
131 return *res_counter_member(counter, member); 144 return *res_counter_member(counter, member);
132} 145}
146#endif
133 147
134int res_counter_memparse_write_strategy(const char *buf, 148int res_counter_memparse_write_strategy(const char *buf,
135 unsigned long long *res) 149 unsigned long long *res)