Messages in this thread | | | Date | Mon, 27 Apr 2020 11:27:07 +0800 | From | Gao Xiang <> | Subject | Re: [RFC PATCH 8/9] orangefs: use set/clear_fs_page_private |
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On Mon, Apr 27, 2020 at 10:58:02AM +0800, Gao Xiang wrote: > On Mon, Apr 27, 2020 at 08:24:55AM +1000, Dave Chinner wrote: > > On Sun, Apr 26, 2020 at 11:49:24PM +0200, Guoqing Jiang wrote: > > > Since the new pair function is introduced, we can call them to clean the > > > code in orangefs. > > > > > > Cc: Mike Marshall <hubcap@omnibond.com> > > > Cc: Martin Brandenburg <martin@omnibond.com> > > > Cc: devel@lists.orangefs.org > > > Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> > > > --- > > > fs/orangefs/inode.c | 24 ++++++------------------ > > > 1 file changed, 6 insertions(+), 18 deletions(-) > > > > > > diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c > > > index 12ae630fbed7..893099d36e20 100644 > > > --- a/fs/orangefs/inode.c > > > +++ b/fs/orangefs/inode.c > > > @@ -64,9 +64,7 @@ static int orangefs_writepage_locked(struct page *page, > > > } > > > if (wr) { > > > kfree(wr); > > > - set_page_private(page, 0); > > > - ClearPagePrivate(page); > > > - put_page(page); > > > + clear_fs_page_private(page); > > > > THis is a pre-existing potential use-after-free vector. The wr > > pointer held in the page->private needs to be cleared from the page > > before it is freed. > > I'm not familar with orangefs. In my opinion, generally all temporary > page->private access (r/w) should be properly protected by some locks,
... page->private pointers (there may be some other uses rather than as references). sorry about that...
> most of time I think it could be at least page lock since .migratepage, > .invalidatepage, .releasepage, .. (such paths) are already called with > page locked (honestly I'm interested in this topic, please correct me > if I'm wrong). > > I agree that the suggested modification is more clear and easy to read. > > Thanks, > Gao Xiang > >
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