cgroup: restructure the failure path in cgroup_write_event_control()
It uses a single label and checks the validity of each pointer. This is err-prone, and actually we had a bug because one of the check was insufficient. Use multi lables as we do in other places. v2: - drop initializations of local variables. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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e14880f7bb
Коммит
876ede8b2b
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@ -3934,11 +3934,11 @@ static void cgroup_event_ptable_queue_proc(struct file *file,
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static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
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const char *buffer)
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{
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struct cgroup_event *event = NULL;
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struct cgroup_event *event;
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struct cgroup *cgrp_cfile;
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unsigned int efd, cfd;
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struct file *efile = NULL;
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struct file *cfile = NULL;
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struct file *efile;
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struct file *cfile;
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char *endp;
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int ret;
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@ -3964,31 +3964,31 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
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efile = eventfd_fget(efd);
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if (IS_ERR(efile)) {
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ret = PTR_ERR(efile);
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goto fail;
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goto out_kfree;
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}
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event->eventfd = eventfd_ctx_fileget(efile);
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if (IS_ERR(event->eventfd)) {
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ret = PTR_ERR(event->eventfd);
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goto fail;
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goto out_put_efile;
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}
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cfile = fget(cfd);
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if (!cfile) {
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ret = -EBADF;
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goto fail;
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goto out_put_eventfd;
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}
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/* the process need read permission on control file */
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/* AV: shouldn't we check that it's been opened for read instead? */
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ret = inode_permission(file_inode(cfile), MAY_READ);
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if (ret < 0)
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goto fail;
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goto out_put_cfile;
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event->cft = __file_cft(cfile);
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if (IS_ERR(event->cft)) {
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ret = PTR_ERR(event->cft);
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goto fail;
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goto out_put_cfile;
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}
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/*
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@ -3998,18 +3998,18 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
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cgrp_cfile = __d_cgrp(cfile->f_dentry->d_parent);
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if (cgrp_cfile != cgrp) {
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ret = -EINVAL;
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goto fail;
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goto out_put_cfile;
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}
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if (!event->cft->register_event || !event->cft->unregister_event) {
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ret = -EINVAL;
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goto fail;
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goto out_put_cfile;
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}
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ret = event->cft->register_event(cgrp, event->cft,
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event->eventfd, buffer);
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if (ret)
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goto fail;
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goto out_put_cfile;
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efile->f_op->poll(efile, &event->pt);
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@ -4029,16 +4029,13 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
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return 0;
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fail:
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if (cfile)
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fput(cfile);
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if (event && event->eventfd && !IS_ERR(event->eventfd))
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eventfd_ctx_put(event->eventfd);
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if (!IS_ERR_OR_NULL(efile))
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fput(efile);
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out_put_cfile:
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fput(cfile);
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out_put_eventfd:
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eventfd_ctx_put(event->eventfd);
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out_put_efile:
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fput(efile);
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out_kfree:
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kfree(event);
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return ret;
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