[PATCH v2 1/4] xen-blkback: fix memory leak when persistent grants are used

From: Roger Pau Monne
Date: Tue Feb 04 2014 - 05:27:46 EST


From: Matt Rushton <mrushton@xxxxxxxxxx>

Currently shrink_free_pagepool() is called before the pages used for
persistent grants are released via free_persistent_gnts(). This
results in a memory leak when a VBD that uses persistent grants is
torn down.

Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: "Roger Pau MonnÃ" <roger.pau@xxxxxxxxxx>
Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: xen-devel@xxxxxxxxxxxxx
Cc: Anthony Liguori <aliguori@xxxxxxxxxx>
Signed-off-by: Matt Rushton <mrushton@xxxxxxxxxx>
Signed-off-by: Matt Wilson <msw@xxxxxxxxxx>
---
drivers/block/xen-blkback/blkback.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 6620b73..30ef7b3 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -625,9 +625,6 @@ purge_gnt_list:
print_stats(blkif);
}

- /* Since we are shutting down remove all pages from the buffer */
- shrink_free_pagepool(blkif, 0 /* All */);
-
/* Free all persistent grant pages */
if (!RB_EMPTY_ROOT(&blkif->persistent_gnts))
free_persistent_gnts(blkif, &blkif->persistent_gnts,
@@ -636,6 +633,9 @@ purge_gnt_list:
BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts));
blkif->persistent_gnt_c = 0;

+ /* Since we are shutting down remove all pages from the buffer */
+ shrink_free_pagepool(blkif, 0 /* All */);
+
if (log_stats)
print_stats(blkif);

--
1.7.7.5 (Apple Git-26)

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