6 files changed, 79 insertions, 70 deletions

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index c12cc362fd3b..3b40d45a3a16 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -531,7 +531,8 @@ static int load_flat_file(struct linux_binprm * bprm,
                 DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
 
                 down_write(&current->mm->mmap_sem);
-                textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, MAP_PRIVATE, 0);
+                textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
+                                  MAP_PRIVATE|MAP_EXECUTABLE, 0);
                 up_write(&current->mm->mmap_sem);
                 if (!textpos  || textpos >= (unsigned long) -4096) {
                         if (!textpos)
diff --git a/fs/exec.c b/fs/exec.c
index 711bc45d789c..a13883903ee9 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -964,6 +964,8 @@ int flush_old_exec(struct linux_binprm * bprm)
         if (retval)
                 goto out;
 
+        set_mm_exe_file(bprm->mm, bprm->file);
+
         /*
          * Release all of the old mmap stuff
          */
diff --git a/fs/proc/base.c b/fs/proc/base.c
index c5e412a00b17..b48ddb119945 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1181,6 +1181,81 @@ static const struct file_operations proc_pid_sched_operations = {
 
 #endif
 
+/*
+ * We added or removed a vma mapping the executable. The vmas are only mapped
+ * during exec and are not mapped with the mmap system call.
+ * Callers must hold down_write() on the mm's mmap_sem for these
+ */
+void added_exe_file_vma(struct mm_struct *mm)
+{
+        mm->num_exe_file_vmas++;
+}
+
+void removed_exe_file_vma(struct mm_struct *mm)
+{
+        mm->num_exe_file_vmas--;
+        if ((mm->num_exe_file_vmas == 0) && mm->exe_file){
+                fput(mm->exe_file);
+                mm->exe_file = NULL;
+        }
+
+}
+
+void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
+{
+        if (new_exe_file)
+                get_file(new_exe_file);
+        if (mm->exe_file)
+                fput(mm->exe_file);
+        mm->exe_file = new_exe_file;
+        mm->num_exe_file_vmas = 0;
+}
+
+struct file *get_mm_exe_file(struct mm_struct *mm)
+{
+        struct file *exe_file;
+
+        /* We need mmap_sem to protect against races with removal of
+         * VM_EXECUTABLE vmas */
+        down_read(&mm->mmap_sem);
+        exe_file = mm->exe_file;
+        if (exe_file)
+                get_file(exe_file);
+        up_read(&mm->mmap_sem);
+        return exe_file;
+}
+
+void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm)
+{
+        /* It's safe to write the exe_file pointer without exe_file_lock because
+         * this is called during fork when the task is not yet in /proc */
+        newmm->exe_file = get_mm_exe_file(oldmm);
+}
+
+static int proc_exe_link(struct inode *inode, struct path *exe_path)
+{
+        struct task_struct *task;
+        struct mm_struct *mm;
+        struct file *exe_file;
+
+        task = get_proc_task(inode);
+        if (!task)
+                return -ENOENT;
+        mm = get_task_mm(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);
+                fput(exe_file);
+                return 0;
+        } else
+                return -ENOENT;
+}
+
 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
         struct inode *inode = dentry->d_inode;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index bc72f5c8c47d..45abb9803988 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -48,7 +48,6 @@ extern int maps_protect;
 
 extern void create_seq_entry(char *name, mode_t mode,
                                 const struct file_operations *f);
-extern int proc_exe_link(struct inode *, struct path *);
 extern int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
                                 struct pid *pid, struct task_struct *task);
 extern int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 7415eeb7cc3a..e2b8e769f510 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -75,40 +75,6 @@ int task_statm(struct mm_struct *mm, int *shared, int *text,
         return mm->total_vm;
 }
 
-int proc_exe_link(struct inode *inode, struct path *path)
-{
-        struct vm_area_struct * vma;
-        int result = -ENOENT;
-        struct task_struct *task = get_proc_task(inode);
-        struct mm_struct * mm = NULL;
-
-        if (task) {
-                mm = get_task_mm(task);
-                put_task_struct(task);
-        }
-        if (!mm)
-                goto out;
-        down_read(&mm->mmap_sem);
-
-        vma = mm->mmap;
-        while (vma) {
-                if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file)
-                        break;
-                vma = vma->vm_next;
-        }
-
-        if (vma) {
-                *path = vma->vm_file->f_path;
-                path_get(&vma->vm_file->f_path);
-                result = 0;
-        }
-
-        up_read(&mm->mmap_sem);
-        mmput(mm);
-out:
-        return result;
-}
-
 static void pad_len_spaces(struct seq_file *m, int len)
 {
         len = 25 + sizeof(void*) * 6 - len;
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 8011528518bd..4b733f108455 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -103,40 +103,6 @@ int task_statm(struct mm_struct *mm, int *shared, int *text,
         return size;
 }
 
-int proc_exe_link(struct inode *inode, struct path *path)
-{
-        struct vm_list_struct *vml;
-        struct vm_area_struct *vma;
-        struct task_struct *task = get_proc_task(inode);
-        struct mm_struct *mm = get_task_mm(task);
-        int result = -ENOENT;
-
-        if (!mm)
-                goto out;
-        down_read(&mm->mmap_sem);
-
-        vml = mm->context.vmlist;
-        vma = NULL;
-        while (vml) {
-                if ((vml->vma->vm_flags & VM_EXECUTABLE) && vml->vma->vm_file) {
-                        vma = vml->vma;
-                        break;
-                }
-                vml = vml->next;
-        }
-
-        if (vma) {
-                *path = vma->vm_file->f_path;
-                path_get(&vma->vm_file->f_path);
-                result = 0;
-        }
-
-        up_read(&mm->mmap_sem);
-        mmput(mm);
-out:
-        return result;
-}
-
 /*
  * display mapping lines for a particular process's /proc/pid/maps
  */