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Diffstat (limited to 'fs/proc/base.c')
-rw-r--r--fs/proc/base.c27
1 files changed, 12 insertions, 15 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3ce5ae9e3d2d..175db258942f 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -234,23 +234,20 @@ static int check_mem_permission(struct task_struct *task)
struct mm_struct *mm_for_maps(struct task_struct *task)
{
- struct mm_struct *mm = get_task_mm(task);
- if (!mm)
+ struct mm_struct *mm;
+
+ if (mutex_lock_killable(&task->cred_guard_mutex))
return NULL;
- down_read(&mm->mmap_sem);
- task_lock(task);
- if (task->mm != mm)
- goto out;
- if (task->mm != current->mm &&
- __ptrace_may_access(task, PTRACE_MODE_READ) < 0)
- goto out;
- task_unlock(task);
+
+ mm = get_task_mm(task);
+ if (mm && mm != current->mm &&
+ !ptrace_may_access(task, PTRACE_MODE_READ)) {
+ mmput(mm);
+ mm = NULL;
+ }
+ mutex_unlock(&task->cred_guard_mutex);
+
return mm;
-out:
- task_unlock(task);
- up_read(&mm->mmap_sem);
- mmput(mm);
- return NULL;
}
static int proc_pid_cmdline(struct task_struct *task, char * buffer)