Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 31/52] 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 | Tue, 10 Dec 2013 00:01:04 -0800 |
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3.10-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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- block/blk-cgroup.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -399,9 +399,9 @@ static inline uint64_t blkg_stat_read(st 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; } @@ -467,9 +467,9 @@ static inline struct blkg_rwstat blkg_rw 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; }
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