| From | Luis Henriques <> | Subject | [PATCH 3.11 051/208] Update of blkg_stat and blkg_rwstat may happen in bh context. While u64_stats_fetch_retry is only preempt_disable on 32bit UP system. This is not enough to avoid preemption by bh and may read strange 64 bit value. | Date | Thu, 19 Dec 2013 11:52:29 +0000 |
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3.11.10.2 -stable review patch. If anyone has any objections, please let me know.
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From: Hong Zhiguo <zhiguohong@tencent.com>
commit 2c575026fae6e63771bd2a4c1d407214a8096a89 upstream.
Signed-off-by: Hong Zhiguo <zhiguohong@tencent.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- block/blk-cgroup.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 8056c03..f50082d 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -433,9 +433,9 @@ static inline uint64_t blkg_stat_read(struct blkg_stat *stat) uint64_t v; do { - start = u64_stats_fetch_begin(&stat->syncp); + start = u64_stats_fetch_begin_bh(&stat->syncp); v = stat->cnt; - } while (u64_stats_fetch_retry(&stat->syncp, start)); + } while (u64_stats_fetch_retry_bh(&stat->syncp, start)); return v; } @@ -501,9 +501,9 @@ static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat) struct blkg_rwstat tmp; do { - start = u64_stats_fetch_begin(&rwstat->syncp); + start = u64_stats_fetch_begin_bh(&rwstat->syncp); tmp = *rwstat; - } while (u64_stats_fetch_retry(&rwstat->syncp, start)); + } while (u64_stats_fetch_retry_bh(&rwstat->syncp, start)); return tmp; } -- 1.8.3.2
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