Hello Robie, I've validated that the package from -proposed works well, testing in my VM based environment. I haven't tested it on Oracle bare metal (where the original issue happened) as that is a type of instance hard to get access to. Given that the test packages had proven to fix the original problem that we were targetting to address, I believe the package from -proposed should also work well. Let me know if it is necessary to also test that it addresses the original issue with Oracle BM host and I'll get access to one and validate.
Regarding your question below: > ...would it be practical and/or useful to verify that, with a timeout of 2s, a DHCP reply sent after 1.5s works, but a DHCP reply sent after 2.5s does not? That has been addressed in comment #30 (and now also in #39 with the package from -proposed). Regarding your question if upstream had accepted the patch, I would have to defer that to Khaled, but I also agree that it seems a deliberate upstream design decision not to accept it. Regarding your comment below: > In Ubuntu, we might decide to maintain the patch as a delta but then drop that delta in subsequent releases when we no longer need that functionality. That is indeed just needed for Bionic. To confirm/clarify my understanding, if this moves to -updates, in theory this is not going to be reverted (from Bionic) in the future, right? Once it lands there, it is expected that any newer klibc-utils packages that gets released to Bionic will continue to carry this patch? Thank you in advance! Regards, Fabio Martins -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to klibc in Ubuntu. https://bugs.launchpad.net/bugs/1947099 Title: ipconfig does not honour user-requested timeouts in some cases Status in klibc package in Ubuntu: Won't Fix Status in klibc source package in Bionic: Fix Committed Bug description: [Impact] In some cases, ipconfig can take a longer time than the user-specified timeouts, causing unexpected delays. [Test Plan] [racb: pending agreement with the SRU team; please see comment 37] Any situation where ipconfig encounters an error sending the DHCP packet, it will automatically set a delay of 10 seconds, which could be longer than the user-specified timeout. It can be reproduced by creating a dummy interface and attempting to run ipconfig on it with a timeout value of less than 10: # ip link add eth1 type dummy # date; /usr/lib/klibc/bin/ipconfig -t 2 eth1; date Thu Nov 18 04:46:13 EST 2021 IP-Config: eth1 hardware address ae:e0:f5:9d:7e:00 mtu 1500 DHCP RARP IP-Config: no response after 2 secs - giving up Thu Nov 18 04:46:23 EST 2021 ^ Notice above, ipconfig thinks that it waited 2 seconds, but the timestamps show an actual delay of 10 seconds. [Where problems could occur] Please see reproduction steps above. We are seeing this in production too (see comment #2). [Other Info] A patch to fix the issue is being proposed here. It is a safe fix - it only checks before going into sleep that the timeout never exceeds the user-requested value. [Original Description] In some cases, ipconfig can take longer than the user-specified timeouts, causing unexpected delays. in main.c, in function loop(), the process can go into process_timeout_event() (or process_receive_event() ) and if it encounters an error situation, will set an attempt to "try again later" at time equal now + 10 seconds by setting s->expire = now + 10; This can happen at any time during the main event loop, which can end up extending the user-specified timeout if "now + 10" is greater than "start_time + user-specified-timeout". I believe a patch like the following is needed to avoid this problem: --- a/usr/kinit/ipconfig/main.c +++ b/usr/kinit/ipconfig/main.c @@ -437,6 +437,13 @@ static int loop(void) if (timeout > s->expire - now.tv_sec) timeout = s->expire - now.tv_sec; + + /* Compensate for already-lost time */ + gettimeofday(&now, NULL); + if (now.tv_sec + timeout > start + loop_timeout) { + timeout = loop_timeout - (now.tv_sec - start); + printf("Lowered timeout to match user request = (%d s) \n", timeout); + } } I believe the current behaviour is buggy. This is confirmed when the following line is executed: if (loop_timeout >= 0 && now.tv_sec - start >= loop_timeout) { printf("IP-Config: no response after %d " "secs - giving up\n", loop_timeout); rc = -1; goto bail; } 'loop_timeout' is the user-specified time-out. With a value of 2, in case of error, this line prints: IP-Config: no response after 2 secs - giving up So it thinks that it waited 2 seconds - however, in reality it had actually waited for 10 seconds. The suggested code-change ensures that the timeout that is actually used never exceeds the user-specified timeout. [ Regression potential ] This change ensures that user-specified timeouts are never exceeded, which is a problem that appears to happen only in case of interface errors. It may be that someone is relying on current behaviour where they receive DHCP offers after their specified timeout (but within the 10-second error timeout). However, 1) that is buggy behaviour and should be exposed. Such a user would need to update their specified timeout to make it long enough to receive the DHCP offer (setting the timeout to 10 would keep the existing behaviour). 2) I think it is unlikely that such a scenario exists at all. The 10-second timeout problem happens when there are problems with the interface that prevent it from even sending out the DHCP request. I think it is very unlikely (or even, impossible) that DHCP offers would be received on a dead interface. Based on the above points, I consider the regression potential to be very low for this change. I do not expect anyone who is currently using ipconfig successfully to notice this change. I believe the only difference introduced by this is the reduction of delays caused by dead or problematic network interfaces. Those error delays are shortened such that they never exceeed user-specified timeouts. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/1947099/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
