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Date: Wed, 20 Aug 2014 18:50:12 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
Cyrill Gorcunov <gorcunov@...nvz.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Greg Ungerer <gerg@...inux.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH -mm 2/2] 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: Oleg Nesterov <oleg@...hat.com>
---
fs/proc/task_mmu.c | 25 +++++++++++++++++++++----
fs/proc/task_nommu.c | 21 ++++++++++++++++++++-
include/linux/mm.h | 4 ++--
mm/util.c | 23 ++++++++---------------
4 files changed, 51 insertions(+), 22 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 828ff49..9d7a9a6 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -262,13 +262,31 @@ 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;
@@ -333,8 +351,7 @@ 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
@@ -1438,7 +1455,7 @@ 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
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index f1cc304..0283e5c 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -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, ' ');
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8981cc8..1c05bd8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -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,
diff --git a/mm/util.c b/mm/util.c
index 093c973..fec39d4 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -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)
--
1.5.5.1
--
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