oom: rewrite error handling for oom_adj and oom_score_adj tunables
It's better to use proper error handling in oom_adjust_write() and oom_score_adj_write() instead of duplicating the locking order on various exit paths. Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -1023,36 +1023,39 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
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memset(buffer, 0, sizeof(buffer));
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if (count > sizeof(buffer) - 1)
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count = sizeof(buffer) - 1;
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if (copy_from_user(buffer, buf, count))
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return -EFAULT;
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if (copy_from_user(buffer, buf, count)) {
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err = -EFAULT;
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goto out;
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}
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err = strict_strtol(strstrip(buffer), 0, &oom_adjust);
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if (err)
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return -EINVAL;
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goto out;
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if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
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oom_adjust != OOM_DISABLE)
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return -EINVAL;
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oom_adjust != OOM_DISABLE) {
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err = -EINVAL;
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goto out;
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}
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task = get_proc_task(file->f_path.dentry->d_inode);
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if (!task)
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return -ESRCH;
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if (!task) {
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err = -ESRCH;
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goto out;
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}
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if (!lock_task_sighand(task, &flags)) {
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put_task_struct(task);
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return -ESRCH;
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err = -ESRCH;
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goto err_task_struct;
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}
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if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
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unlock_task_sighand(task, &flags);
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put_task_struct(task);
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return -EACCES;
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err = -EACCES;
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goto err_sighand;
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}
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task_lock(task);
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if (!task->mm) {
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task_unlock(task);
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unlock_task_sighand(task, &flags);
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put_task_struct(task);
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return -EINVAL;
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err = -EINVAL;
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goto err_task_lock;
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}
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if (oom_adjust != task->signal->oom_adj) {
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@ -1080,11 +1083,14 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
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else
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task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
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-OOM_DISABLE;
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err_task_lock:
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task_unlock(task);
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err_sighand:
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unlock_task_sighand(task, &flags);
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err_task_struct:
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put_task_struct(task);
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return count;
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out:
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return err < 0 ? err : count;
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}
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static const struct file_operations proc_oom_adjust_operations = {
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@ -1125,36 +1131,39 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
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memset(buffer, 0, sizeof(buffer));
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if (count > sizeof(buffer) - 1)
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count = sizeof(buffer) - 1;
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if (copy_from_user(buffer, buf, count))
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return -EFAULT;
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if (copy_from_user(buffer, buf, count)) {
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err = -EFAULT;
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goto out;
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}
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err = strict_strtol(strstrip(buffer), 0, &oom_score_adj);
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if (err)
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return -EINVAL;
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goto out;
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if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
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oom_score_adj > OOM_SCORE_ADJ_MAX)
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return -EINVAL;
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oom_score_adj > OOM_SCORE_ADJ_MAX) {
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err = -EINVAL;
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goto out;
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}
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task = get_proc_task(file->f_path.dentry->d_inode);
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if (!task)
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return -ESRCH;
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if (!task) {
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err = -ESRCH;
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goto out;
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}
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if (!lock_task_sighand(task, &flags)) {
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put_task_struct(task);
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return -ESRCH;
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err = -ESRCH;
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goto err_task_struct;
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}
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if (oom_score_adj < task->signal->oom_score_adj &&
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!capable(CAP_SYS_RESOURCE)) {
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unlock_task_sighand(task, &flags);
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put_task_struct(task);
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return -EACCES;
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err = -EACCES;
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goto err_sighand;
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}
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task_lock(task);
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if (!task->mm) {
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task_unlock(task);
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unlock_task_sighand(task, &flags);
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put_task_struct(task);
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return -EINVAL;
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err = -EINVAL;
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goto err_task_lock;
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}
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if (oom_score_adj != task->signal->oom_score_adj) {
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if (oom_score_adj == OOM_SCORE_ADJ_MIN)
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@ -1172,10 +1181,14 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
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else
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task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
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OOM_SCORE_ADJ_MAX;
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err_task_lock:
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task_unlock(task);
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err_sighand:
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unlock_task_sighand(task, &flags);
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err_task_struct:
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put_task_struct(task);
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return count;
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out:
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return err < 0 ? err : count;
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}
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static const struct file_operations proc_oom_score_adj_operations = {
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