Messages in this thread |  | | From | Waiman Long <> | Subject | [PATCH v4 0/2] blk-cgroup: Fix potential UAF & flush rstat at blkgs destruction path | Date | Wed, 14 Dec 2022 22:31:30 -0500 |
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v4: - Update comment and commit logs for both patches.
v3: - Drop v2 patch 2 as it may not be needed. - Replace css_tryget() with percpu_ref_is_zero() in patch 1 as suggested by Tejun. - Expand comment on patch 2 to elaborate the reason for this patch.
v2: - Remove unnecessary rcu_read_{lock|unlock} from cgroup_rstat_css_cpu_flush() in patch 3.
It was found that blkcg_destroy_blkgs() may be called with all blkcg references gone. This may potentially cause user-after-free and so should be fixed. The second patch flushes rstat when calling blkcg_destroy_blkgs().
Waiman Long (2): bdi, blk-cgroup: Fix potential UAF of blkcg blk-cgroup: Flush stats at blkgs destruction path
block/blk-cgroup.c | 23 +++++++++++++++++++++++ include/linux/cgroup.h | 1 + kernel/cgroup/rstat.c | 18 ++++++++++++++++++ mm/backing-dev.c | 8 ++++++-- 4 files changed, 48 insertions(+), 2 deletions(-)
-- 2.31.1
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