From: Giacomo Tesio <giacomo@tesio.it>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] Privalloc(2) and rfork(RFPROC|RFMEM) (was: a pair nec bugs)
Date: Sun, 6 Sep 2015 01:03:38 +0200 [thread overview]
Message-ID: <CAHL7psH78FA_APWfZjTkEbxp0BCqLChwED7xgtUVu48WZ54SJw@mail.gmail.com> (raw)
In-Reply-To: <8b5a65de5cd93ec6242b885530caf86f@brasstown.quanstro.net>
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2015-09-05 20:47 GMT+02:00 erik quanstrom <quanstro@quanstro.net>:
> > May be my problem is that p is global in my case?
>
> global variables are in the bss, and thus shared. p will have
> the same value in each thread, but *p should point into the
> stack, and thus the same virtual address will be mapped to
> different physical pages of memory.
>
> however, if *p is assigned to a non-zero value before the process
> is created, the new page allocated for the new process' stack will
> have a copy of the old value, and thus not be 0.
>
> - erik
>
>
That's exactly what happened.
I misread privalloc(2), and assumed that privalloc()ed addresses were
somehow reset on rfork.
This is probably something to explicitly state the man page.
Thanks you all!
Giacomo
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next prev parent reply other threads:[~2015-09-05 23:03 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-05 14:03 Giacomo Tesio
2015-09-05 14:11 ` Giacomo Tesio
2015-09-05 15:27 ` erik quanstrom
2015-09-05 16:41 ` erik quanstrom
2015-09-05 18:42 ` Giacomo Tesio
2015-09-05 18:47 ` erik quanstrom
2015-09-05 23:03 ` Giacomo Tesio [this message]
2015-09-05 18:56 ` cinap_lenrek
2015-09-05 22:45 ` Charles Forsyth
2015-09-05 23:38 ` cinap_lenrek
2015-09-06 13:14 ` erik quanstrom
2015-09-06 14:12 ` Charles Forsyth
2015-09-06 15:02 ` erik quanstrom
2015-09-06 20:21 ` Charles Forsyth
2015-09-07 0:30 ` erik quanstrom
2015-09-07 9:38 ` Charles Forsyth
2015-09-07 11:59 ` Charles Forsyth
2015-09-06 18:21 ` cinap_lenrek
2015-09-06 20:27 ` Charles Forsyth
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