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>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6e50c8e..34d11ac 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1023,36 +1023,39 @@
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
- if (copy_from_user(buffer, buf, count))
- return -EFAULT;
+ if (copy_from_user(buffer, buf, count)) {
+ err = -EFAULT;
+ goto out;
+ }
err = strict_strtol(strstrip(buffer), 0, &oom_adjust);
if (err)
- return -EINVAL;
+ goto out;
if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
- oom_adjust != OOM_DISABLE)
- return -EINVAL;
+ oom_adjust != OOM_DISABLE) {
+ err = -EINVAL;
+ goto out;
+ }
task = get_proc_task(file->f_path.dentry->d_inode);
- if (!task)
- return -ESRCH;
+ if (!task) {
+ err = -ESRCH;
+ goto out;
+ }
if (!lock_task_sighand(task, &flags)) {
- put_task_struct(task);
- return -ESRCH;
+ err = -ESRCH;
+ goto err_task_struct;
}
if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
- unlock_task_sighand(task, &flags);
- put_task_struct(task);
- return -EACCES;
+ err = -EACCES;
+ goto err_sighand;
}
task_lock(task);
if (!task->mm) {
- task_unlock(task);
- unlock_task_sighand(task, &flags);
- put_task_struct(task);
- return -EINVAL;
+ err = -EINVAL;
+ goto err_task_lock;
}
if (oom_adjust != task->signal->oom_adj) {
@@ -1080,11 +1083,14 @@
else
task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
-OOM_DISABLE;
+err_task_lock:
task_unlock(task);
+err_sighand:
unlock_task_sighand(task, &flags);
+err_task_struct:
put_task_struct(task);
-
- return count;
+out:
+ return err < 0 ? err : count;
}
static const struct file_operations proc_oom_adjust_operations = {
@@ -1125,36 +1131,39 @@
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
- if (copy_from_user(buffer, buf, count))
- return -EFAULT;
+ if (copy_from_user(buffer, buf, count)) {
+ err = -EFAULT;
+ goto out;
+ }
err = strict_strtol(strstrip(buffer), 0, &oom_score_adj);
if (err)
- return -EINVAL;
+ goto out;
if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
- oom_score_adj > OOM_SCORE_ADJ_MAX)
- return -EINVAL;
+ oom_score_adj > OOM_SCORE_ADJ_MAX) {
+ err = -EINVAL;
+ goto out;
+ }
task = get_proc_task(file->f_path.dentry->d_inode);
- if (!task)
- return -ESRCH;
+ if (!task) {
+ err = -ESRCH;
+ goto out;
+ }
if (!lock_task_sighand(task, &flags)) {
- put_task_struct(task);
- return -ESRCH;
+ err = -ESRCH;
+ goto err_task_struct;
}
if (oom_score_adj < task->signal->oom_score_adj &&
!capable(CAP_SYS_RESOURCE)) {
- unlock_task_sighand(task, &flags);
- put_task_struct(task);
- return -EACCES;
+ err = -EACCES;
+ goto err_sighand;
}
task_lock(task);
if (!task->mm) {
- task_unlock(task);
- unlock_task_sighand(task, &flags);
- put_task_struct(task);
- return -EINVAL;
+ err = -EINVAL;
+ goto err_task_lock;
}
if (oom_score_adj != task->signal->oom_score_adj) {
if (oom_score_adj == OOM_SCORE_ADJ_MIN)
@@ -1172,10 +1181,14 @@
else
task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
OOM_SCORE_ADJ_MAX;
+err_task_lock:
task_unlock(task);
+err_sighand:
unlock_task_sighand(task, &flags);
+err_task_struct:
put_task_struct(task);
- return count;
+out:
+ return err < 0 ? err : count;
}
static const struct file_operations proc_oom_score_adj_operations = {