Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [PATCH 3/3] aio_free_ring: don't do page_count(NULL) | Date | Wed, 17 Jun 2015 14:26:28 -0400 |
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Oleg Nesterov <oleg@redhat.com> writes:
> aio_free_ring() can actually see the NULL page in ->ring_pages[], > this can happen if aio_setup_ring() fails. > > And in this case page_count(ctx->ring_pages[i]) can OOPS. > > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
I'm not sure the reformatting was necessary, but whatever.
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
> --- > fs/aio.c | 8 ++++---- > 1 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/fs/aio.c b/fs/aio.c > index b605ab2..666fbb8 100644 > --- a/fs/aio.c > +++ b/fs/aio.c > @@ -292,12 +292,12 @@ static void aio_free_ring(struct kioctx *ctx) > put_aio_ring_file(ctx); > > for (i = 0; i < ctx->nr_pages; i++) { > - struct page *page; > - pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i, > - page_count(ctx->ring_pages[i])); > - page = ctx->ring_pages[i]; > + struct page *page = ctx->ring_pages[i]; > if (!page) > continue; > + > + pr_debug("pid(%d) [%d] page->count=%d\n", > + current->pid, i, page_count(page)); > ctx->ring_pages[i] = NULL; > put_page(page); > }
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