[PATCH-block,v2,0/3] blk-cgroup: Fix potential UAF & miscellaneous cleanup

Message

Waiman Long Dec. 11, 2022, 10:20 p.m. UTC

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 last 2 patches are miscellaneous cleanups of
commit 3b8cc6298724 ("blk-cgroup: Optimize blkcg_rstat_flush()").

Waiman Long (3):
  bdi, blk-cgroup: Fix potential UAF of blkcg
  blk-cgroup: Don't flush a blkg if destroyed
  blk-cgroup: Flush stats at blkgs destruction path

 block/blk-cgroup.c     | 26 ++++++++++++++++++++++++++
 include/linux/cgroup.h |  1 +
 kernel/cgroup/rstat.c  | 18 ++++++++++++++++++
 mm/backing-dev.c       |  8 ++++++--
 4 files changed, 51 insertions(+), 2 deletions(-)