[PATCH RESEND] cgroup: remove subsystem files when remounting cgroup
From: Gao feng <hidden>
Date: 2012-12-03 01:50:22
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
cgroup_clear_directroy is called by cgroup_d_remove_dir and cgroup_remount. when we call cgroup_remount to remount the cgroup,the subsystem may be unlinked from cgroupfs_root->subsys_list in rebind_subsystem,this subsystem's files will not be removed in cgroup_clear_directroy. And the system will panic when we try to access these files. this patch removes subsystems's files before rebind_subsystems, if rebind_subsystems failed, repopulate these removed files. With help from Tejun. Signed-off-by: Gao feng <redacted> --- kernel/cgroup.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index e1293a9..afabd2a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c@@ -1349,14 +1349,21 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data) goto out_unlock; } + /* + * Clear out the files of subsystems that should be removed,do + * this job before rebind_subsystems,since rebind_subsystems may + * change this hierarchy's subsys_list. + */ + cgroup_clear_directory(cgrp->dentry, false, removed_mask); + ret = rebind_subsystems(root, opts.subsys_mask); if (ret) { + /* rebind_subsystems failed,re-populate the removed files */ + cgroup_populate_dir(cgrp, false, removed_mask); drop_parsed_module_refcounts(opts.subsys_mask); goto out_unlock; } - /* clear out any existing files and repopulate subsystem files */ - cgroup_clear_directory(cgrp->dentry, false, removed_mask); /* re-populate subsystem files */ cgroup_populate_dir(cgrp, false, added_mask);
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1.7.7.6