This is a note to let you know that I've just added the patch titled tipc: allow non-linear first fragment buffer to the 4.1-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: tipc-allow-non-linear-first-fragment-buffer.patch and it can be found in the queue-4.1 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 Tue Nov 17 14:35:45 PST 2015 From: Jon Paul Maloy <jon.maloy@xxxxxxxxxxxx> Date: Mon, 19 Oct 2015 11:33:00 -0400 Subject: tipc: allow non-linear first fragment buffer From: Jon Paul Maloy <jon.maloy@xxxxxxxxxxxx> [ Upstream commit 45c8b7b175ceb2d542e0fe15247377bf3bce29ec ] The current code for message reassembly is erroneously assuming that the the first arriving fragment buffer always is linear, and then goes ahead resetting the fragment list of that buffer in anticipation of more arriving fragments. However, if the buffer already happens to be non-linear, we will inadvertently drop the already attached fragment list, and later on trig a BUG() in __pskb_pull_tail(). We see this happen when running fragmented TIPC multicast across UDP, something made possible since commit d0f91938bede ("tipc: add ip/udp media type") We fix this by not resetting the fragment list when the buffer is non- linear, and by initiatlizing our private fragment list tail pointer to the tail of the existing fragment list. Fixes: commit d0f91938bede ("tipc: add ip/udp media type") Signed-off-by: Jon Maloy <jon.maloy@xxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/tipc/msg.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -121,7 +121,7 @@ int tipc_buf_append(struct sk_buff **hea { struct sk_buff *head = *headbuf; struct sk_buff *frag = *buf; - struct sk_buff *tail; + struct sk_buff *tail = NULL; struct tipc_msg *msg; u32 fragid; int delta; @@ -141,9 +141,15 @@ int tipc_buf_append(struct sk_buff **hea if (unlikely(skb_unclone(frag, GFP_ATOMIC))) goto err; head = *headbuf = frag; - skb_frag_list_init(head); - TIPC_SKB_CB(head)->tail = NULL; *buf = NULL; + TIPC_SKB_CB(head)->tail = NULL; + if (skb_is_nonlinear(head)) { + skb_walk_frags(head, tail) { + TIPC_SKB_CB(head)->tail = tail; + } + } else { + skb_frag_list_init(head); + } return 0; } Patches currently in stable-queue which might be from jon.maloy@xxxxxxxxxxxx are queue-4.1/tipc-allow-non-linear-first-fragment-buffer.patch queue-4.1/tipc-linearize-arriving-name_distr-and-link_proto-buffers.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