From: Oleg Nesterov <oleg@redhat.com>
To: Al Viro <viro@ZenIV.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Benjamin LaHaise <bcrl@kvack.org>, Jeff Moyer <jmoyer@redhat.com>
Cc: linux-aio@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH 3/3] aio_free_ring: don't do page_count(NULL)
Date: Wed, 17 Jun 2015 01:04:31 +0200 [thread overview]
Message-ID: <20150616230431.GA15800@redhat.com> (raw)
In-Reply-To: <20150616230414.GA15776@redhat.com>
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>
---
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);
}
--
1.5.5.1
next prev parent reply other threads:[~2015-06-16 23:05 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-16 23:04 [PATCH 0/3] aio: ctx->dead cleanups Oleg Nesterov
2015-06-16 23:04 ` [PATCH 1/3] aio_ring_remap: turn the ctx->dead check into WARN_ON() Oleg Nesterov
2015-06-17 17:50 ` Jeff Moyer
2015-06-17 18:42 ` Oleg Nesterov
2015-06-16 23:04 ` [PATCH 2/3] aio: make aio_ring->dead boolean Oleg Nesterov
2015-06-16 23:50 ` [PATCH v2 " Oleg Nesterov
2015-06-17 19:33 ` Jeff Moyer
2015-06-16 23:04 ` Oleg Nesterov [this message]
2015-06-17 18:26 ` [PATCH 3/3] aio_free_ring: don't do page_count(NULL) Jeff Moyer
2015-06-17 0:39 ` [PATCH 0/3] aio: ctx->dead cleanups Al Viro
2015-06-17 0:50 ` Al Viro
2015-06-17 1:22 ` Oleg Nesterov
2015-06-18 16:08 ` Oleg Nesterov
2015-06-17 1:05 ` Oleg Nesterov
2015-06-17 1:14 ` Oleg Nesterov
2015-06-17 1:32 ` Oleg Nesterov
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