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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Kostik Belousov <kostikbel@gmail.com>
References: <201009160756.o8G7uZrg065332@svn.freebsd.org>
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	<20100924115311.GH34228@deviant.kiev.zoral.com.ua>
Date: Sat, 25 Sep 2010 01:49:59 +0200
In-Reply-To: <20100924115311.GH34228@deviant.kiev.zoral.com.ua> (Kostik
	Belousov's message of "Fri, 24 Sep 2010 14:53:11 +0300")
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Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org,
	pluknet <pluknet@gmail.com>, src-committers@freebsd.org
Subject: Re: svn commit: r212723 - head/sys/compat/linprocfs
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Kostik Belousov <kostikbel@gmail.com> writes:
> This is easy to fix, isn't it ? But there seems to be much more nits.
>
> First, allocating 512 * sizeof(char *)-byte object on the stack is not
> good.
>
> Second, the initialization of iov_len for reading the array
> of string pointers misses '* sizeof(char *)'.
>
> And third (probably fatal) is the lack of checks that the end of
> array and each string fits into the user portion of the map. I do not
> see why addr that already has u_long type is casted to u_long. Also,
> VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS constants are for the native host
> FreeBSD ABI, they may differ from the target process limits.

Blah, I clearly didn't look closely enough at the final version.  The
original patch used malloc() but introduced a potential race condition
due to having to drop the process lock.  I wrote a version that used
_PHOLD() / _PRELE() to hold the process across the unlock / malloc /
lock window, but the originator had trouble with it (albeit only in
qemu, not on real hardware), and I wasn't 100% sure my reasoning was
sound, so I accepted his suggested solution.  I'll look into this
tomorrow.

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no