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authorDave Chinner <dchinner@redhat.com>2022-05-04 04:45:11 +0300
committerDave Chinner <david@fromorbit.com>2022-05-04 04:45:11 +0300
commitc230a4a85bcdbfc1a7415deec6caf04e8fca1301 (patch)
treea4af7219fbf72c0350d6c08eea91825c20cfde9e /fs/xfs/xfs_bmap_item.c
parentcb512c921639613ce03f87e62c5e93ed9fe8c84d (diff)
downloadlinux-c230a4a85bcdbfc1a7415deec6caf04e8fca1301.tar.xz
xfs: fix potential log item leak
Ever since we added shadown format buffers to the log items, log items need to handle the item being released with shadow buffers attached. Due to the fact this requirement was added at the same time we added new rmap/reflink intents, we missed the cleanup of those items. In theory, this means shadow buffers can be leaked in a very small window when a shutdown is initiated. Testing with KASAN shows this leak does not happen in practice - we haven't identified a single leak in several years of shutdown testing since ~v4.8 kernels. However, the intent whiteout cleanup mechanism results in every cancelled intent in exactly the same state as this tiny race window creates and so if intents down clean up shadow buffers on final release we will leak the shadow buffer for just about every intent we create. Hence we start with this patch to close this condition off and ensure that when whiteouts start to be used we don't leak lots of memory. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/xfs_bmap_item.c')
-rw-r--r--fs/xfs/xfs_bmap_item.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 593ac29cffc7..2c8b686e2a11 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -39,6 +39,7 @@ STATIC void
xfs_bui_item_free(
struct xfs_bui_log_item *buip)
{
+ kmem_free(buip->bui_item.li_lv_shadow);
kmem_cache_free(xfs_bui_cache, buip);
}
@@ -198,6 +199,7 @@ xfs_bud_item_release(
struct xfs_bud_log_item *budp = BUD_ITEM(lip);
xfs_bui_release(budp->bud_buip);
+ kmem_free(budp->bud_item.li_lv_shadow);
kmem_cache_free(xfs_bud_cache, budp);
}