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oom: rewrite error handling for oom_adj and oom_score_adj tunables

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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>
This commit is contained in:
David Rientjes 2010-10-26 14:21:25 -07:00 committed by Linus Torvalds
parent 1e99bad0d9
commit 723548bff1
1 changed files with 48 additions and 35 deletions
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83
fs/proc/base.c
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@ -1023,36 +1023,39 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
memset(buffer, 0, sizeof(buffer)); memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1) if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1; count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count)) if (copy_from_user(buffer, buf, count)) {
return -EFAULT; err = -EFAULT;
goto out;
}
err = strict_strtol(strstrip(buffer), 0, &oom_adjust); err = strict_strtol(strstrip(buffer), 0, &oom_adjust);
if (err) if (err)
return -EINVAL; goto out;
if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) && if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) &&
oom_adjust != OOM_DISABLE) oom_adjust != OOM_DISABLE) {
return -EINVAL; err = -EINVAL;
goto out;
}
task = get_proc_task(file->f_path.dentry->d_inode); task = get_proc_task(file->f_path.dentry->d_inode);
if (!task) if (!task) {
return -ESRCH; err = -ESRCH;
goto out;
}
if (!lock_task_sighand(task, &flags)) { if (!lock_task_sighand(task, &flags)) {
put_task_struct(task); err = -ESRCH;
return -ESRCH; goto err_task_struct;
} }
if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) { if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
unlock_task_sighand(task, &flags); err = -EACCES;
put_task_struct(task); goto err_sighand;
return -EACCES;
} }
task_lock(task); task_lock(task);
if (!task->mm) { if (!task->mm) {
task_unlock(task); err = -EINVAL;
unlock_task_sighand(task, &flags); goto err_task_lock;
put_task_struct(task);
return -EINVAL;
} }
if (oom_adjust != task->signal->oom_adj) { 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 else
task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) / task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
-OOM_DISABLE; -OOM_DISABLE;
err_task_lock:
task_unlock(task); task_unlock(task);
err_sighand:
unlock_task_sighand(task, &flags); unlock_task_sighand(task, &flags);
err_task_struct:
put_task_struct(task); put_task_struct(task);
out:
return count; return err < 0 ? err : count;
} }
static const struct file_operations proc_oom_adjust_operations = { 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)); memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1) if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1; count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count)) if (copy_from_user(buffer, buf, count)) {
return -EFAULT; err = -EFAULT;
goto out;
}
err = strict_strtol(strstrip(buffer), 0, &oom_score_adj); err = strict_strtol(strstrip(buffer), 0, &oom_score_adj);
if (err) if (err)
return -EINVAL; goto out;
if (oom_score_adj < OOM_SCORE_ADJ_MIN || if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
oom_score_adj > OOM_SCORE_ADJ_MAX) oom_score_adj > OOM_SCORE_ADJ_MAX) {
return -EINVAL; err = -EINVAL;
goto out;
}
task = get_proc_task(file->f_path.dentry->d_inode); task = get_proc_task(file->f_path.dentry->d_inode);
if (!task) if (!task) {
return -ESRCH; err = -ESRCH;
goto out;
}
if (!lock_task_sighand(task, &flags)) { if (!lock_task_sighand(task, &flags)) {
put_task_struct(task); err = -ESRCH;
return -ESRCH; goto err_task_struct;
} }
if (oom_score_adj < task->signal->oom_score_adj && if (oom_score_adj < task->signal->oom_score_adj &&
!capable(CAP_SYS_RESOURCE)) { !capable(CAP_SYS_RESOURCE)) {
unlock_task_sighand(task, &flags); err = -EACCES;
put_task_struct(task); goto err_sighand;
return -EACCES;
} }
task_lock(task); task_lock(task);
if (!task->mm) { if (!task->mm) {
task_unlock(task); err = -EINVAL;
unlock_task_sighand(task, &flags); goto err_task_lock;
put_task_struct(task);
return -EINVAL;
} }
if (oom_score_adj != task->signal->oom_score_adj) { if (oom_score_adj != task->signal->oom_score_adj) {
if (oom_score_adj == OOM_SCORE_ADJ_MIN) 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 else
task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) / task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
OOM_SCORE_ADJ_MAX; OOM_SCORE_ADJ_MAX;
err_task_lock:
task_unlock(task); task_unlock(task);
err_sighand:
unlock_task_sighand(task, &flags); unlock_task_sighand(task, &flags);
err_task_struct:
put_task_struct(task); put_task_struct(task);
return count; out:
return err < 0 ? err : count;
} }
static const struct file_operations proc_oom_score_adj_operations = { static const struct file_operations proc_oom_score_adj_operations = {