summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--fs/proc/base.c7
-rw-r--r--include/linux/mm.h1
-rw-r--r--kernel/fork.c23
3 files changed, 25 insertions, 6 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index e8bbf6cdb437..d2b8c754f627 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1545,18 +1545,13 @@ static const struct file_operations proc_pid_set_comm_operations = {
static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
{
struct task_struct *task;
- struct mm_struct *mm;
struct file *exe_file;
task = get_proc_task(d_inode(dentry));
if (!task)
return -ENOENT;
- mm = get_task_mm(task);
+ exe_file = get_task_exe_file(task);
put_task_struct(task);
- if (!mm)
- return -ENOENT;
- exe_file = get_mm_exe_file(mm);
- mmput(mm);
if (exe_file) {
*exe_path = exe_file->f_path;
path_get(&exe_file->f_path);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8a761248d01e..cfebb742ee18 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1898,6 +1898,7 @@ extern void mm_drop_all_locks(struct mm_struct *mm);
extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
extern struct file *get_mm_exe_file(struct mm_struct *mm);
+extern struct file *get_task_exe_file(struct task_struct *task);
extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
diff --git a/kernel/fork.c b/kernel/fork.c
index c485cb156772..8860d1f50d24 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -764,6 +764,29 @@ struct file *get_mm_exe_file(struct mm_struct *mm)
EXPORT_SYMBOL(get_mm_exe_file);
/**
+ * get_task_exe_file - acquire a reference to the task's executable file
+ *
+ * Returns %NULL if task's mm (if any) has no associated executable file or
+ * this is a kernel thread with borrowed mm (see the comment above get_task_mm).
+ * User must release file via fput().
+ */
+struct file *get_task_exe_file(struct task_struct *task)
+{
+ struct file *exe_file = NULL;
+ struct mm_struct *mm;
+
+ task_lock(task);
+ mm = task->mm;
+ if (mm) {
+ if (!(task->flags & PF_KTHREAD))
+ exe_file = get_mm_exe_file(mm);
+ }
+ task_unlock(task);
+ return exe_file;
+}
+EXPORT_SYMBOL(get_task_exe_file);
+
+/**
* get_task_mm - acquire a reference to the task's mm
*
* Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning