This is a note to let you know that I've just added the patch titled skbuff: skb_copy_ubufs must release uarg even without user frags to the 4.14-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: skbuff-skb_copy_ubufs-must-release-uarg-even-without-user-frags.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sun Dec 31 11:12:48 CET 2017 From: Willem de Bruijn <willemb@xxxxxxxxxx> Date: Wed, 20 Dec 2017 17:37:50 -0500 Subject: skbuff: skb_copy_ubufs must release uarg even without user frags From: Willem de Bruijn <willemb@xxxxxxxxxx> [ Upstream commit b90ddd568792bcb0054eaf0f61785c8f80c3bd1c ] skb_copy_ubufs creates a private copy of frags[] to release its hold on user frags, then calls uarg->callback to notify the owner. Call uarg->callback even when no frags exist. This edge case can happen when zerocopy_sg_from_iter finds enough room in skb_headlen to copy all the data. Fixes: 3ece782693c4 ("sock: skb_copy_ubufs support for compound pages") Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/core/skbuff.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1182,7 +1182,7 @@ int skb_copy_ubufs(struct sk_buff *skb, u32 d_off; if (!num_frags) - return 0; + goto release; if (skb_shared(skb) || skb_unclone(skb, gfp_mask)) return -EINVAL; @@ -1242,6 +1242,7 @@ int skb_copy_ubufs(struct sk_buff *skb, __skb_fill_page_desc(skb, new_frags - 1, head, 0, d_off); skb_shinfo(skb)->nr_frags = new_frags; +release: skb_zcopy_clear(skb, false); return 0; } Patches currently in stable-queue which might be from willemb@xxxxxxxxxx are queue-4.14/skbuff-skb_copy_ubufs-must-release-uarg-even-without-user-frags.patch queue-4.14/sock-free-skb-in-skb_complete_tx_timestamp-on-error.patch queue-4.14/skbuff-orphan-frags-before-zerocopy-clone.patch queue-4.14/skbuff-in-skb_copy_ubufs-unclone-before-releasing-zerocopy.patch