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

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- 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: Oleg 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2014-10-09 15:25:54 -07:00 committed by Linus Torvalds
parent 2c03376d2d
commit 58cb65487e
4 changed files with 51 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
fs/proc/task_mmu.c
View File

@ -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

21
fs/proc/task_nommu.c
View File

@ -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, ' ');

4
include/linux/mm.h
View File

@ -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,

23
mm/util.c
View File

@ -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)