> I will attempt to upstream this fix to klibc, but I believe the change
to Bionic should happen in parallel/independently since the upstream
patch will not make its way back to Bionic (which is stuck at 2.0.4, as
mentioned above).
Yes that is the plan to SRU the fix on top of what is currently found in
Bionic's klibc.
And I'll gladly sponsor your patch in Bionic.
The idea with upstream is to make our contribution available to other
who may suffer from the same issue, make sure it won't re-occur in a
future release of Ubuntu as we will sync from debian which sync from
upstream, ... and also have some kind of upstream
adoption/approval/review of your proposal fix.
Let's give a few days after the submission for the upstream to have some
time to review your patch. If it takes too long for them to get back to
us, I'll sponsor the patch as-is, knowing that it was submitted to
upstream with a reasonable amount of time given to them to review.
- Eric
** Changed in: klibc (Ubuntu Bionic)
Assignee: (unassigned) => Khaled El Mously (kmously)
** Changed in: klibc (Ubuntu Bionic)
Status: New => In Progress
--
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:
New
Status in klibc source package in Bionic:
In Progress
Bug description:
[Impact]
In some cases, ipconfig can take a longer time than the user-specified
timeouts, causing unexpected delays.
[Test Plan]
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.
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 : touch-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~touch-packages
More help : https://help.launchpad.net/ListHelp
