lkml.org 
[lkml]   [2020]   [Jul]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 1/1] mm/vmalloc.c: Add an error message if two areas overlap
On Fri, Jul 10, 2020 at 09:01:38PM +0100, Matthew Wilcox wrote:
> On Fri, Jul 10, 2020 at 10:00:30PM +0200, Uladzislau Rezki wrote:
> > On Fri, Jul 10, 2020 at 08:44:06PM +0100, Matthew Wilcox wrote:
> > > On Fri, Jul 10, 2020 at 09:40:42PM +0200, Uladzislau Rezki (Sony) wrote:
> > > > Before triggering a BUG() it would be useful to understand
> > > > how two areas overlap between each other. Print information
> > > > about start/end addresses of both VAs and their addresses.
> > > >
> > > > For example if both are identical it could mean double free.
> > > >
> > > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> > > > ---
> > > > mm/vmalloc.c | 10 +++++++++-
> > > > 1 file changed, 9 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> > > > index 5a2b55c8dd9a..1679b01febcd 100644
> > > > --- a/mm/vmalloc.c
> > > > +++ b/mm/vmalloc.c
> > > > @@ -549,8 +549,13 @@ find_va_links(struct vmap_area *va,
> > > > else if (va->va_end > tmp_va->va_start &&
> > > > va->va_start >= tmp_va->va_end)
> > > > link = &(*link)->rb_right;
> > > > - else
> > > > + else {
> > > > + pr_err("Overlaps: 0x%px(0x%lx-0x%lx), 0x%px(0x%lx-0x%lx)\n",
> > > > + va, va->va_start, va->va_end, tmp_va,
> > > > + tmp_va->va_start, tmp_va->va_end);
> > >
> > > It might be helpful to have a "vmalloc:" prefix to that string to indicate
> > > where to start searching. And I don't think we're supposed to use %px
> > > without a really good justification these days.
> > >
> > That makes sense, i will add such prefix for sure. As for %px i can just
> > use a casting to (unsigned long) and 0x%lx prefix.
>
> That's not the point. Linus wants us to not display actual pointers to
> the user.
>
Ahh, Got it!

Then i will just remove information about addresses of two VAs.
Hope that will work.

--
Vlad Rezki

\
 
 \ /
  Last update: 2020-07-10 22:04    [W:0.050 / U:0.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site