Commit 4177e496 authored Dec 07, 2021 by Eric Dumazet Committed by Jakub Kicinski Dec 09, 2021

xfrm: use net device refcount tracker helpers



xfrm4_fill_dst() and xfrm6_fill_dst() build dst,
getting a device reference that will likely be released
by standard dst_release() code.

We have to track these references or risk a warning if
CONFIG_NET_DEV_REFCNT_TRACKER=y

Note to XFRM maintainers :

Error path in xfrm6_fill_dst() releases the reference,
but does not clear xdst->u.dst.dev, so I wonder
if this could lead to double dev_put() in some cases,
where a dst_release() _is_ called by the callers in their
error path.

This extra dev_put() was added in commit 84c4a9df ("xfrm6:
release dev before returning error")

Fixes: 9038c320 ("net: dst: add net device refcount tracking to dst_entry")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Cong Wang <amwang@redhat.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Link: https://lore.kernel.org/r/20211207193203.2706158-1-eric.dumazet@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent 5092fb44

net/ipv4/xfrm4_policy.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -77,7 +77,7 @@ static int xfrm4_fill_dst(struct xfrm_dst xdst, struct net_device dev,
		xdst->u.rt.rt_iif = fl4->flowi4_iif;

		xdst->u.dst.dev = dev;
		dev_hold(dev);
		dev_hold_track(dev, &xdst->u.dst.dev_tracker, GFP_ATOMIC);

		/* Sheit... I remember I did this right. Apparently,
		* it was magically lost, so this code needs audit */

net/ipv6/xfrm6_policy.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -74,11 +74,11 @@ static int xfrm6_fill_dst(struct xfrm_dst xdst, struct net_device dev,
		struct rt6_info rt = (struct rt6_info )xdst->route;

		xdst->u.dst.dev = dev;
		dev_hold(dev);
		dev_hold_track(dev, &xdst->u.dst.dev_tracker, GFP_ATOMIC);

		xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
		if (!xdst->u.rt6.rt6i_idev) {
		dev_put(dev);
		dev_put_track(dev, &xdst->u.dst.dev_tracker);
		return -ENODEV;
		}