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Tejun Heo authored
If a cgroup file implements either read_map() or read_seq_string(), such file is served using seq_file by overriding file->f_op to cgroup_seqfile_operations, which also overrides the release method to single_release() from cgroup_file_release(). Because cgroup_file_open() didn't use to acquire any resources, this used to be fine, but since f7d58818 ("cgroup: pin cgroup_subsys_state when opening a cgroupfs file"), cgroup_file_open() pins the css (cgroup_subsys_state) which is put by cgroup_file_release(). The patch forgot to update the release path for seq_files and each open/release cycle leaks a css reference. Fix it by updating cgroup_file_release() to also handle seq_files and using it for seq_file release path too. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v3.12
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