From: David Rientjes <rientjes@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-mm@kvack.org
Subject: [patch -mm 1/2] oom: rewrite error handling for oom_adj and oom_score_adj tunables
Date: Mon, 23 Aug 2010 18:36:33 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1008231829230.6483@chino.kir.corp.google.com> (raw)
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>
---
fs/proc/base.c | 83 ++++++++++++++++++++++++++++++++-----------------------
1 files changed, 48 insertions(+), 35 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1023,36 +1023,39 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
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 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
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 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
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 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
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 = {
--
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next reply other threads:[~2010-08-24 1:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-24 1:36 David Rientjes [this message]
2010-08-24 1:36 ` [patch -mm 2/2] oom: protect task name when killing threads sharing memory David Rientjes
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