On 03/15, Steven Rostedt wrote:
>
> On Tue, 13 Mar 2018 18:26:00 +0530
> Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxxxxxxx> wrote:
>
> > +static void sdt_increment_ref_ctr(struct trace_uprobe *tu)
> > +{
> > + struct uprobe_map_info *info;
> > + struct vm_area_struct *vma;
> > + unsigned long vaddr;
> > +
> > + uprobe_start_dup_mmap();
>
> Please add a comment here that this function ups the mm ref count for
> each info returned. Otherwise it's hard to know what that mmput() below
> matches.
You meant uprobe_build_map_info(), not uprobe_start_dup_mmap().
Yes, and if it gets more callers perhaps we should move this mmput() into
uprobe_free_map_info()...
Oleg.
--- x/kernel/events/uprobes.c
+++ x/kernel/events/uprobes.c
@@ -714,6 +714,7 @@ struct map_info {
static inline struct map_info *free_map_info(struct map_info *info)
{
struct map_info *next = info->next;
+ mmput(info->mm);
kfree(info);
return next;
}
@@ -783,8 +784,11 @@ build_map_info(struct address_space *map
goto again;
out:
- while (prev)
- prev = free_map_info(prev);
+ while (prev) {
+ info = prev;
+ prev = prev->next;
+ kfree(info);
+ }
return curr;
}
@@ -834,7 +838,6 @@ register_for_each_vma(struct uprobe *upr
unlock:
up_write(&mm->mmap_sem);
free:
- mmput(mm);
info = free_map_info(info);
}
out:
