2005-01-14 21:13:12

by Prasanna Meda

Subject: [patch]: fix loss of records on size > 4096 in proc/<pid>/maps

5th: Moved the in-range map's version update logic to m_show from
m_start and m_next. This fixes the loss of records on the reads of
size > 4096 on boundaries.

Jeremy, can you please verify it now? This is on top of 2.6.10-mm3.


--- a/fs/task_mmu.c Fri Jan 14 00:21:23 2005
+++ b/fs/task_mmu.c Fri Jan 14 20:20:10 2005
@@ -79,6 +79,7 @@ out:

static int show_map(struct seq_file *m, void *v)
{
+ struct task_struct *task = m->private;
struct vm_area_struct *map = v;
struct file *file = map->vm_file;
int flags = map->vm_flags;
@@ -110,6 +111,8 @@ static int show_map(struct seq_file *m,
seq_path(m, file->f_vfsmnt, file->f_dentry, "");
}
seq_putc(m, '\n');
+ if (m->count < m->size) /* map is copied successfully */
+ m->version = (map != get_gate_vma(task))? map->vm_start: 0;
return 0;
}

@@ -132,10 +135,8 @@ static void *m_start(struct seq_file *m,
return NULL;

mm = get_task_mm(task);
- if (!mm) {
- m->version = -1UL;
+ if (!mm)
return NULL;
- }

tail_map = get_gate_vma(task);
down_read(&mm->mmap_sem);
@@ -162,13 +163,11 @@ static void *m_start(struct seq_file *m,
tail_map = NULL; /* After gate map */

out:
- if (map && map != tail_map) {
- m->version = map->vm_start;
+ if (map)
return map;
- }

/* End of maps has reached */
- m->version = -1UL;
+ m->version = (tail_map != NULL)? 0: -1UL;
up_read(&mm->mmap_sem);
mmput(mm);
return tail_map;
@@ -192,12 +191,9 @@ static void *m_next(struct seq_file *m,
struct vm_area_struct *tail_map = get_gate_vma(task);

(*pos)++;
- if (map && (map != tail_map) && map->vm_next) {
- m->version = map->vm_next->vm_start;
+ if (map && (map != tail_map) && map->vm_next)
return map->vm_next;
- }
m_stop(m, v);
- m->version = -1UL;
return (map != tail_map)? tail_map: NULL;
}