Messages in this thread |  | | From | John Alvord <> | Subject | Re: [PATCH][RFC] Pollable /proc/<pid>/ - avoid SIGCHLD/poll() races | Date | Sat, 13 Oct 2001 19:25:03 -0700 |
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On Sat, 13 Oct 2001 17:36:19 +0200, Jamie Lokier <lk@tantalophile.demon.co.uk> wrote:
>Mattias Engdegård wrote: >> I don't think it's contrived --- writing not a byte, but the pid and >> return status of the dead child to a pipe is an old but useful trick. >> It gives a natural serialisation of child deaths, and also eliminates >> the common race where a child dies before its parent has recorded its >> pid in a data structure. See it as a safe way of converting an >> asynchronous signal to a queued event. >> >> Using pipes to wake up blocking select()s is a useful thing in general, >> and often a lot cleaner than using signals when dealing with threads. > >This mistake is exactly the reason that Netscape 4.x freezes from time >to time on Linux. > >It tries to write too many things to a pipe, making the assumption that >this will never happen.
At one point a few years ago, someone implemented a loadable library which "fixed" the Netscape problem by knowing what the bug was, doing things the right way, and presenting the interface Netscape expected.
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