Hi Matthew, See below for my comment. Also, although this is about a different problem, you should check if you have the following patch, and the one it is referring to: commit 06bd2b1ed04ca9f (" tipc: fix broadcast link synchronization problem")
> -----Original Message----- > From: Wong, Matthew [mailto:mw...@sonusnet.com] > Sent: Wednesday, February 22, 2017 12:41 PM > To: tipc-discussion@lists.sourceforge.net > Subject: [tipc-discussion] tipc multicast stuck (hit max window) due to > invalid > bc_ack value > > > Hi all, > > I'm currently working on 4.4.0 kernel and is observing the following issues > on tipc multicast. > > > 1. I have a system setup with 3 CPUs each using tipc to multicast to > processes running on each CPU. After sending around 50 messages (the max > window size), the far end did not receive the message any more. When > Iooking at the tipc-conf -ls data, it said the broadcast-link start bunding [...] > > 4. It seems the tipc_msg_validate modified the skb message and the hdr. > The modified data looks fine and has the correct expected bc-ack/ack values > in the message. However, currently the bc_ack and ack value is initialized > before the tipc_msg_validate and so we'll use that value which may cause > issue on my bc_ack update and comparsion. The only possible culprit here is the function skb_may_pull(), which is called from msg_validate() in the rare case that header part of the packet buffer is non-linear. The function is a little hard to follow, but as I understand it, it linearizes the buffer in such cases, and header fields read before the validation will obviously be wrong. > > > > 5 If i move the bc_ack and ack after tipc_msg_validate, i don't have > any > more tipc multicast stuck issue. I have run it for half a day with multicast > on 4 > CPUs and so far there is no tipc multicast bundle trigger and no bogus bc_ack > issue. All multicast messges has been sent and received properly. > > > > 6 Is this a known behavior and is this an issue? If yes, is this a > patch for it > and will 4.4.48 has the same issue? Does the tipc_msg_validate function > suppose to modify the hdr data and should we use the bc_ack/ack values > afterwards the modification is completed. We have never seen this before, but your diagnostics is totally credible. I will post a patch for this asap. Nice job! BR ///jon > > > > Any comment is appreciated. > > > > Regards, > > Matthew > > Sonus network. > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most engaging > tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > tipc-discussion mailing list > tipc-discussion@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/tipc-discussion ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ tipc-discussion mailing list tipc-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tipc-discussion