Re: [PATCH] ceph: fix memory leak in async readpages

[Jeff Wu <cpwu@tnsoft.com.cn>]

Hi ,

take the following steps:

$mount -t ceph monip:6789:/ /mnt/ceph
$dd if=/dev/zero of=/mnt/ceph/2G bs=1M count=2048 conv=fsync
----------------
copy_test:
#!/bin/bash
cp /mnt/ceph/2G /mnt/$1/
------------------

$copy_test 01 &
$copy_test 02 &
$copy_test 03 &
$copy_test 04 &
$copy_test 05 &
$copy_test 06 &
$copy_test 07 &
$copy_test 08 &
$copy_test 09 &




Jeff


On Tue, 2011-10-25 at 00:09 +0800, Sage Weil wrote:
> Thanks, Jeff!
> 
> Was there a workload that reliably triggered this case?
> 
> sage
> 
> 
> On Mon, 24 Oct 2011, Jeff Wu wrote:
> 
> > Hi ,
> > 
> > start_read() do twice "kfree(pages)",
> > 
> > ................
> >  out_pages:
> >         ceph_release_page_vector(pages, nr_pages);
> >         kfree(pages);
> > 
> > 
> > ceph_release_page_vector had kfree pages, continue to do kfree(pages),
> > sometimes ,async read ,printk "BUG kmalloc-16: Object already
> > free" ,then OOPS.
> > 
> > Jeff Wu
> > 
> > ----------------------------------------------------------------------
> > void ceph_release_page_vector(struct page **pages, int num_pages)
> > {
> > 	int i;
> > 
> > 	for (i = 0; i < num_pages; i++)
> > 		__free_pages(pages[i], 0);
> > 	kfree(pages);
> > }
> > 
> > 
> > $ git diff
> > diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> > index 5ffee90..4144caf 100644
> > --- a/fs/ceph/addr.c
> > +++ b/fs/ceph/addr.c
> > @@ -345,7 +345,6 @@ static int start_read(struct inode *inode, struct
> > list_head *page_list, int max)
> >  
> >  out_pages:
> >         ceph_release_page_vector(pages, nr_pages);
> > -       kfree(pages);
> >  out:
> >         ceph_osdc_put_request(req);
> >         return ret;
> > 
> > 
> > On Thu, 2011-09-29 at 03:16 +0800, Sage Weil wrote:
> > > On Wed, 28 Sep 2011, Sage Weil wrote:
> > > > I'll send this upstream with the other patches so it'll hopefully make 
> > > > 3.1...
> > > 
> > > Er, not really.. this'll go upstream during the next merge window, along 
> > > with the readahead code.  :)
> > > 
> > > sage
> > > 
> > > 
> > > > 
> > > > Thanks!
> > > > sage
> > > > 
> > > > 
> > > > On Wed, 28 Sep 2011, David Flynn wrote:
> > > > 
> > > > > The finish_read callback introduced in 63c90314546c1cec1f220f6ab24ea
> > > > > fails to release the page list allocated in start_read.
> > > > > ---
> > > > >  fs/ceph/addr.c |    1 +
> > > > >  1 files changed, 1 insertions(+), 0 deletions(-)
> > > > > 
> > > > > diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> > > > > index e06a322..4144caf 100644
> > > > > --- a/fs/ceph/addr.c
> > > > > +++ b/fs/ceph/addr.c
> > > > > @@ -261,6 +261,7 @@ static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
> > > > >  		unlock_page(page);
> > > > >  		page_cache_release(page);
> > > > >  	}
> > > > > +	kfree(req->r_pages);
> > > > >  }
> > > > >  
> > > > >  /*
> > > > > -- 
> > > > > 1.7.4.1
> > > > > --
> > > > > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
> > > > > the body of a message to majordomo@vger.kernel.org
> > > > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > > > > 
> > > > > 
> > > > --
> > > > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
> > > > the body of a message to majordomo@vger.kernel.org
> > > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > > > 
> > > > 
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> >