[3.19.y-ckt stable] Patch "ovl: fix dentry reference leak" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Thu Nov 12 23:14:57 UTC 2015
This is a note to let you know that I have just added a patch titled
ovl: fix dentry reference leak
to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue
This patch is scheduled to be released in version 3.19.8-ckt10.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From 92c6b06a634445951b71009261c16029e381aa89 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells at redhat.com>
Date: Fri, 18 Sep 2015 11:45:22 +0100
Subject: [PATCH 104/120] ovl: fix dentry reference leak
commit ab79efab0a0ba01a74df782eb7fa44b044dae8b5 upstream.
In ovl_copy_up_locked(), newdentry is leaked if the function exits through
out_cleanup as this just to out after calling ovl_cleanup() - which doesn't
actually release the ref on newdentry.
The out_cleanup segment should instead exit through out2 as certainly
newdentry leaks - and possibly upper does also, though this isn't caught
given the catch of newdentry.
Without this fix, something like the following is seen:
BUG: Dentry ffff880023e9eb20{i=f861,n=#ffff880023e82d90} still in use (1) [unmount of tmpfs tmpfs]
BUG: Dentry ffff880023ece640{i=0,n=bigfile} still in use (1) [unmount of tmpfs tmpfs]
when unmounting the upper layer after an error occurred in copyup.
An error can be induced by creating a big file in a lower layer with
something like:
dd if=/dev/zero of=/lower/a/bigfile bs=65536 count=1 seek=$((0xf000))
to create a large file (4.1G). Overlay an upper layer that is too small
(on tmpfs might do) and then induce a copy up by opening it writably.
Reported-by: Ulrich Obergfell <uobergfe at redhat.com>
Signed-off-by: David Howells <dhowells at redhat.com>
Signed-off-by: Miklos Szeredi <miklos at szeredi.hu>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
fs/overlayfs/copy_up.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 94edf78..319c487 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -268,7 +268,7 @@ out:
out_cleanup:
ovl_cleanup(wdir, newdentry);
- goto out;
+ goto out2;
}
/*
--
1.9.1
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