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authorOleg Nesterov <oleg@redhat.com>2014-10-09 15:25:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-09 22:25:50 -0400
commit58cb65487e92b47448d00a711c9f5922137d5678 (patch)
treeee260fe8859876f861b07d131eab07a35617b426
parent2c03376d2db005869b1d4449097d51c96196529e (diff)
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@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>
-rw-r--r--fs/proc/task_mmu.c25
-rw-r--r--fs/proc/task_nommu.c21
-rw-r--r--include/linux/mm.h4
-rw-r--r--mm/util.c23
4 files changed, 51 insertions, 22 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 4793e4a843b0..adddf697c4ea 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -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
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index f36e213835cc..599ec2e20104 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 0f4196a0bc20..28df70774b81 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 093c973f1697..fec39d4509a9 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)