On Mon, 2016-08-22 at 01:00 -0700, Joe Perches wrote:

On Mon, 2016-08-22 at 09:24 +0200, Michal Hocko wrote:

quoted

On Sat 20-08-16 01:00:17, Joe Perches wrote:

[]

quoted

quoted

static int proc_maps_open(struct inode *inode, struct file *file,
 			const struct seq_operations *ops, int psize)
 {
-	struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
+	struct proc_maps_private *priv;
+	struct mm_struct *mm;
+
+	mm = proc_mem_open(inode, PTRACE_MODE_READ);
+	if (IS_ERR(mm))
+		return PTR_ERR(mm);
 
+	priv = __seq_open_private_bufsize(file, ops, psize,
+					  mm && mm->map_count ?
+					  mm->map_count * 0x300 : PAGE_SIZE);

NAK to this!

Seriously, this just gives any random user access to user
defined amount of memory which not accounted, not reclaimable and a
potential consumer of any higher order blocks.

I completely disagree here with your rationale here.

And with further review and your comment above, I withdraw this patch.
cheers, Joe

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