This is a note to let you know that I've just added the patch titled
ovl: fix dentry reference leak
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ovl-fix-dentry-reference-leak.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ab79efab0a0ba01a74df782eb7fa44b044dae8b5 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@xxxxxxxxxx>
Date: Fri, 18 Sep 2015 11:45:22 +0100
Subject: ovl: fix dentry reference leak
From: David Howells <dhowells@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Miklos Szeredi <miklos@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/overlayfs/copy_up.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -267,7 +267,7 @@ out:
out_cleanup:
ovl_cleanup(wdir, newdentry);
- goto out;
+ goto out2;
}
/*
Patches currently in stable-queue which might be from dhowells@xxxxxxxxxx are
queue-4.2/ovl-fix-dentry-reference-leak.patch
queue-4.2/ovl-use-o_largefile-in-ovl_copy_up.patch
queue-4.2/ovl-fix-open-in-stacked-overlay.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html