Affected: Linux, linux_kernel

In the Linux kernel, the following vulnerability has been resolved:

blk-cgroup: fix list corruption from reorder of WRITE ->lqueued

__blkcg_rstat_flush() can be run anytime, especially when blk_cgroup_bio_start is being executed.

If WRITE of `->lqueued` is re-ordered with READ of 'bisc->lnode.next' in the loop of __blkcg_rstat_flush(), `next_bisc` can be assigned with one stat instance being added in blk_cgroup_bio_start(), then the local list in __blkcg_rstat_flush() could be corrupted.

Fix the issue by adding one barrier.