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Commit 58cb6548 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

proc/maps: make vm_is_stack() logic namespace-friendly 



- Rename vm_is_stack() to task_of_stack() and change it to return
  "struct task_struct *" rather than the global (and thus wrong in
  general) pid_t.

- Add the new pid_of_stack() helper which calls task_of_stack() and
  uses the right namespace to report the correct pid_t.

  Unfortunately we need to define this helper twice, in task_mmu.c
  and in task_nommu.c. perhaps it makes sense to add fs/proc/util.c
  and move at least pid_of_stack/task_of_stack there to avoid the
  code duplication.

- Change show_map_vma() and show_numa_map() to use the new helper.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2c03376d

fs/proc/task_mmu.c

+21 −4
Original line number Diff line number Diff line
@@ -261,13 +261,31 @@ static int do_maps_open(struct inode *inode, struct file *file, 
				sizeof(struct proc_maps_private));

}



static pid_t pid_of_stack(struct proc_maps_private *priv,

				struct vm_area_struct *vma, bool is_pid)

{

	struct inode *inode = priv->inode;

	struct task_struct *task;

	pid_t ret = 0;



	rcu_read_lock();

	task = pid_task(proc_pid(inode), PIDTYPE_PID);

	if (task) {

		task = task_of_stack(task, vma, is_pid);

		if (task)

			ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info);

	}

	rcu_read_unlock();



	return ret;

}



static void

show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)

{

	struct mm_struct *mm = vma->vm_mm;

	struct file *file = vma->vm_file;

	struct proc_maps_private *priv = m->private;

	struct task_struct *task = priv->task;

	vm_flags_t flags = vma->vm_flags;

	unsigned long ino = 0;

	unsigned long long pgoff = 0;
@@ -332,8 +350,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid) 
			goto done;

		}



		tid = vm_is_stack(task, vma, is_pid);



		tid = pid_of_stack(priv, vma, is_pid);

		if (tid != 0) {

			/*

			 * Thread stack in /proc/PID/task/TID/maps or
@@ -1446,7 +1463,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid) 
	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {

		seq_puts(m, " heap");

	} else {

		pid_t tid = vm_is_stack(task, vma, is_pid);

		pid_t tid = pid_of_stack(proc_priv, vma, is_pid);

		if (tid != 0) {

			/*

			 * Thread stack in /proc/PID/task/TID/maps or

fs/proc/task_nommu.c

+20 −1
Original line number Diff line number Diff line
@@ -123,6 +123,25 @@ unsigned long task_statm(struct mm_struct *mm, 
	return size;

}



static pid_t pid_of_stack(struct proc_maps_private *priv,

				struct vm_area_struct *vma, bool is_pid)

{

	struct inode *inode = priv->inode;

	struct task_struct *task;

	pid_t ret = 0;



	rcu_read_lock();

	task = pid_task(proc_pid(inode), PIDTYPE_PID);

	if (task) {

		task = task_of_stack(task, vma, is_pid);

		if (task)

			ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info);

	}

	rcu_read_unlock();



	return ret;

}



/*

 * display a single VMA to a sequenced file

 */
@@ -163,7 +182,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma, 
		seq_pad(m, ' ');

		seq_path(m, &file->f_path, "");

	} else if (mm) {

		pid_t tid = vm_is_stack(priv->task, vma, is_pid);

		pid_t tid = pid_of_stack(priv, vma, is_pid);



		if (tid != 0) {

			seq_pad(m, ' ');

include/linux/mm.h

+2 −2
Original line number Diff line number Diff line
@@ -1247,8 +1247,8 @@ static inline int stack_guard_page_end(struct vm_area_struct *vma, 
		!vma_growsup(vma->vm_next, addr);

}



extern pid_t

vm_is_stack(struct task_struct *task, struct vm_area_struct *vma, int in_group);

extern struct task_struct *task_of_stack(struct task_struct *task,

				struct vm_area_struct *vma, bool in_group);



extern unsigned long move_page_tables(struct vm_area_struct *vma,

		unsigned long old_addr, struct vm_area_struct *new_vma,

mm/util.c

+8 −15
Original line number Diff line number Diff line
@@ -170,32 +170,25 @@ static int vm_is_stack_for_task(struct task_struct *t, 
/*

 * Check if the vma is being used as a stack.

 * If is_group is non-zero, check in the entire thread group or else

 * just check in the current task. Returns the pid of the task that

 * the vma is stack for.

 * just check in the current task. Returns the task_struct of the task

 * that the vma is stack for. Must be called under rcu_read_lock().

 */

pid_t vm_is_stack(struct task_struct *task,

		  struct vm_area_struct *vma, int in_group)

struct task_struct *task_of_stack(struct task_struct *task,

				struct vm_area_struct *vma, bool in_group)

{

	pid_t ret = 0;



	if (vm_is_stack_for_task(task, vma))

		return task->pid;

		return task;



	if (in_group) {

		struct task_struct *t;



		rcu_read_lock();

		for_each_thread(task, t) {

			if (vm_is_stack_for_task(t, vma)) {

				ret = t->pid;

				goto done;

			}

			if (vm_is_stack_for_task(t, vma))

				return t;

		}

done:

		rcu_read_unlock();

	}



	return ret;

	return NULL;

}



#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)