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Bugzilla: 1112975
Upstream-status: 3.16 and CC'd to stable
From f8567a3845ac05bb28f3c1b478ef752762bd39ef Mon Sep 17 00:00:00 2001
From: Benjamin LaHaise <bcrl@kvack.org>
Date: Tue, 24 Jun 2014 13:12:55 -0400
Subject: [PATCH] aio: fix aio request leak when events are reaped by userspace
The aio cleanups and optimizations by kmo that were merged into the 3.10
tree added a regression for userspace event reaping. Specifically, the
reference counts are not decremented if the event is reaped in userspace,
leading to the application being unable to submit further aio requests.
This patch applies to 3.12+. A separate backport is required for 3.10/3.11.
This issue was uncovered as part of CVE-2014-0206.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Cc: stable@vger.kernel.org
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Petr Matousek <pmatouse@redhat.com>
---
fs/aio.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index 4f078c054b41..6a9c7e489adf 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1021,6 +1021,7 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
/* everything turned out well, dispose of the aiocb. */
kiocb_free(iocb);
+ put_reqs_available(ctx, 1);
/*
* We have to order our ring_info tail store above and test
@@ -1100,8 +1101,6 @@ static long aio_read_events_ring(struct kioctx *ctx,
flush_dcache_page(ctx->ring_pages[0]);
pr_debug("%li h%u t%u\n", ret, head, tail);
-
- put_reqs_available(ctx, ret);
out:
mutex_unlock(&ctx->ring_lock);
--
1.9.3
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