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From: Junio C Hamano <gitster@pobox.com>
To: szager@google.com
Cc: git@vger.kernel.org, sop@google.com
Subject: Re: Fix potential hang in https handshake (v2).
Date: Thu, 18 Oct 2012 17:37:45 -0700	[thread overview]
Message-ID: <7v4nlrl2jq.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <7v8vb3l2q5.fsf@alter.siamese.dyndns.org> (Junio C. Hamano's message of "Thu, 18 Oct 2012 17:33:54 -0700")

Junio C Hamano <gitster@pobox.com> writes:

> We end up calling select() without any bit set in fds, so it would
> become micro-sleep of select_timeout in such a case, but as far as I
> can see, the existing code either
>
>  * does not select() and keeps polling step_active_slots() without
>    delay, when curl_timeout gives a 0 return value; or
>
>  * sets 50ms timeout or whatever negative value derived from
>    curl_timeout when the returned value is not 0 nor -1.
>
> Is the symptom that select(), when given a negative timeout and no
> fd to wake it, sleeps forever (or "loooong time, taking that negative
> value as if it is a large unsigned long") or something?

Addendum.

What I am trying to get at are (1) three line description I can put
in the release notes for this fix when it is merged to the
maintenance track, and (2) a feel of how often this happens and how
bad the damage is.

The latter helps us judge if this "do the normal thing, but if in a
rare case where we do not find any fds, patch it up to proceed" is a
better approach over your original.

Thanks.

      reply	other threads:[~2012-10-19  0:38 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-18 23:27 Fix potential hang in https handshake (v2) szager
2012-10-19  0:33 ` Junio C Hamano
2012-10-19  0:37   ` Junio C Hamano [this message]

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