report errors in /proc/*/*map* sanely

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2011-02-15 22:22:54 -05:00
parent ca6b0bf0e0
commit ec6fd8a435
3 changed files with 13 additions and 11 deletions

View file

@ -225,15 +225,17 @@ static int check_mem_permission(struct task_struct *task)
struct mm_struct *mm_for_maps(struct task_struct *task)
{
struct mm_struct *mm;
int err;
if (mutex_lock_killable(&task->signal->cred_guard_mutex))
return NULL;
err = mutex_lock_killable(&task->signal->cred_guard_mutex);
if (err)
return ERR_PTR(err);
mm = get_task_mm(task);
if (mm && mm != current->mm &&
!ptrace_may_access(task, PTRACE_MODE_READ)) {
mmput(mm);
mm = NULL;
mm = ERR_PTR(-EACCES);
}
mutex_unlock(&task->signal->cred_guard_mutex);

View file

@ -119,11 +119,11 @@ static void *m_start(struct seq_file *m, loff_t *pos)
priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
if (!priv->task)
return NULL;
return ERR_PTR(-ESRCH);
mm = mm_for_maps(priv->task);
if (!mm)
return NULL;
if (!mm || IS_ERR(mm))
return mm;
down_read(&mm->mmap_sem);
tail_vma = get_gate_vma(priv->task);
@ -728,9 +728,9 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
if (!task)
goto out;
ret = -EACCES;
mm = mm_for_maps(task);
if (!mm)
ret = PTR_ERR(mm);
if (!mm || IS_ERR(mm))
goto out_task;
ret = -EINVAL;

View file

@ -199,13 +199,13 @@ static void *m_start(struct seq_file *m, loff_t *pos)
/* pin the task and mm whilst we play with them */
priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
if (!priv->task)
return NULL;
return ERR_PTR(-ESRCH);
mm = mm_for_maps(priv->task);
if (!mm) {
if (!mm || IS_ERR(mm)) {
put_task_struct(priv->task);
priv->task = NULL;
return NULL;
return mm;
}
down_read(&mm->mmap_sem);