Use of pool servers reveals unacceptable crash rate in async DNS
hmurray at megapathdsl.net
Sun Jun 26 00:37:13 UTC 2016
esr at thyrsus.com said:
> I think the hack is to force libgcc_s to be loaded early. I don't know how
> to do that in waf.
There are two problems in this area. One is the end-of-thread code not
getting locked into memory. I think that is what you are running into.
The other is a tangle of error handling on out-of-memory issues by things
like pthread_create and DNS lookup. I think the latter end up with a retry
error code. I think I fixed some/many of them to crash rather than retry on
the assumption that memory wasn't going to get freed and I didn't know of any
other reason to retry. But that was a long time ago (maybe pre fork) and I
don't remember the details.
I think we should copy the warmup code from ntp classic. It's basically an
upstream bug. Warmup seems like a reasonable work around.
It's in ntpd/ntpd.c Search for NEED_PTHREAD_WARMUP and backup over the long
which describes what's going on.
There is a note about not working on FreeBSD. I haven't sorted that out. It
may refer to the linker hack.
Here are the bugs I remember:
FreeBSD page fault story, morphs into lock discussion
There is more info in various bugs:
The signal/noise may not be good.
These are my opinions. I hate spam.
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