[Olsr-dev] info plugin still send blocking

[Joe Ayers]

Correction, full strace log file URL is:

https://drive.google.com/file/d/1TGW5VFpcKppbd82eT72qf6TqTtgqy-0j/view?usp=sharing



On Mon, Dec 4, 2017 at 10:36 AM, Joe Ayers <(spam-protected)> wrote:
> In reference to:
>
> " * A timer was added and each time it expires each non-empty buffer
>   * in this structure will try to write data into a "non-blocking"
>   * socket until all data is sent, so that no blocking occurs."
>
> A blocking event can be reliably reproduced in olsr 0.9.6.2 in OpenWRT
> Chaos Calmer.  The node drops off the mesh and stops responding (not a
> good thing when it's remote on a tower :) ).
>
> Test scenario:
>
> - Node_A LAN laptop, "echo /all | nc node_B 9090"  sleeps 2 seconds
> and repeats (reproduces more quickly, but could be a single hit)
> - Node_A has RF link to Node_B with ~70% LQ/NLQ (maybe marginal LQ/NLQ
> is a non-factor?)
> - Node_B has "echo /nei | nc localhost 2006" sleeps 5 seconds and repeats
>
> After a few minutes, Node_B blocks on send in strace,  subsequently
> waited ~10 min and SIGTERM'd  (search for SIGTERM to find in full log
> file URL below).
>
> clock_gettime(CLOCK_MONOTONIC, {281, 819282014}) = 0
> accept(13, {sa_family=AF_INET, sin_port=htons(32965),
> sin_addr=inet_addr("10.34.163.239")}, [16]) = 17
> _newselect(18, [17], NULL, NULL, {0, 20000}) = 1 (in [17], left {0, 19984})
> recv(17, "/all\n", 1024, MSG_DONTWAIT)  = 5
> time(NULL)                              = 1512345153
> clock_gettime(CLOCK_MONOTONIC, {281, 825309152}) = 0
> ...
> clock_gettime(CLOCK_MONOTONIC, {282, 416388829}) = 0
> _newselect(18, NULL, [17], NULL, {0, 0}) = 1 (out [17], left {0, 0})
> send(17, "{\"pid\": 1726,\"systemTime\": 15123"..., 386040, 0) = 141904
>
> OLSR no longer functions at this point in time, remaining TCP
> connections go to CLOSE_WAIT until socket listen limit reached.
> Shouldn't there be a MSG_DONTWAIT flag in the send to be non-blocking?
>
> Full strace log:
> https://drive.google.com/file/d/0B2bEy75HhwWhVE1BQ3BUdHY3azg/view?usp=sharing
>
> Joe AE6XE