lkml.org 
[lkml]   [2018]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 5/8] trace_uprobe: Support SDT markers having reference count (semaphore)
On 03/15, Steven Rostedt wrote:
>
> On Tue, 13 Mar 2018 18:26:00 +0530
> Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> 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:
\
 
 \ /
  Last update: 2018-03-16 17:17    [W:0.249 / U:4.616 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site