From: Shailabh Nagar <nagar@watson.ibm.com>
To: Paul Jackson <pj@sgi.com>
Cc: akpm@osdl.org, Valdis.Kletnieks@vt.edu, jlan@engr.sgi.com,
balbir@in.ibm.com, csturtiv@sgi.com,
linux-kernel@vger.kernel.org, hadi@cyberus.ca,
netdev@vger.kernel.org
Subject: Re: [Patch][RFC] Disabling per-tgid stats on task exit in taskstats
Date: Mon, 03 Jul 2006 20:09:13 -0400 [thread overview]
Message-ID: <44A9B1A9.20106@watson.ibm.com> (raw)
In-Reply-To: <20060703093148.5e61a7e4.pj@sgi.com>
Paul Jackson wrote:
>Shailabh wrote:
>
>
>>I don't know if there are buffer overflow
>>issues in passing a string
>>
>>
>
>I don't know if this comment applies to "the standard netlink way of
>passing it up using NLA_STRING", but the way I deal with buffer length
>issues in the cpuset code is to insist that the user code express the
>list in no fewer than 100 + 6 * NR_CPUS bytes:
>
>From kernel/cpuset.c:
>
> /* Crude upper limit on largest legitimate cpulist user might write. */
> if (nbytes > 100 + 6 * NR_CPUS)
> return -E2BIG;
>
>This lets the user specify the buffer size passed in, but prevents
>them from trying a denial of service attack on the kernel by trying
>to pass in a huge buffer.
>
>If the user can't figure out how to write the desired cpulist in
>that size, then tough toenails.
>
>
Paul,
Perhaps I should use the the other ascii format for specifying cpumasks
since its more amenable
to specifying an upper bound for the length of the ascii string and is
more compact ?
That format (the one used in lib/bitmap.c:bitmap_parse) is comma
separated chunks of hex digits
with each chunk specifying 32 bits of the desired cpumask.
So
((NR_CPUS + 32) / 32) * 8 + 1
(8 hex characters for each 32 cpus, and 1 extra character for null
terminator)
would be an upper bound that would accomodate all the cpus for sure.
Thoughts ?
--Shailabh
--Shailabh
next prev parent reply other threads:[~2006-07-04 0:09 UTC|newest]
Thread overview: 134+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-09 7:41 [Patch][RFC] Disabling per-tgid stats on task exit in taskstats Shailabh Nagar
2006-06-09 8:00 ` Andrew Morton
2006-06-09 10:51 ` Balbir Singh
2006-06-09 11:21 ` Andrew Morton
2006-06-09 13:20 ` Shailabh Nagar
2006-06-09 18:25 ` Jay Lan
2006-06-09 19:12 ` Shailabh Nagar
2006-06-09 15:36 ` Balbir Singh
2006-06-09 18:35 ` Jay Lan
2006-06-09 19:31 ` Shailabh Nagar
2006-06-09 21:56 ` Shailabh Nagar
2006-06-09 22:42 ` Jay Lan
2006-06-09 23:22 ` Andrew Morton
2006-06-09 23:47 ` Jay Lan
2006-06-09 23:56 ` Andrew Morton
2006-06-10 12:21 ` Shailabh Nagar
2006-06-12 18:31 ` Jay Lan
2006-06-12 21:57 ` Shailabh Nagar
2006-06-10 13:05 ` Shailabh Nagar
2006-06-12 18:54 ` Jay Lan
2006-06-21 19:11 ` Jay Lan
2006-06-21 19:14 ` Jay Lan
2006-06-21 19:34 ` Shailabh Nagar
2006-06-21 23:35 ` Jay Lan
2006-06-21 23:45 ` Shailabh Nagar
2006-06-23 17:14 ` Shailabh Nagar
2006-06-23 18:19 ` Jay Lan
2006-06-23 18:53 ` Shailabh Nagar
2006-06-23 20:00 ` Jay Lan
2006-06-23 20:16 ` Shailabh Nagar
2006-06-23 20:36 ` Jay Lan
2006-06-23 21:19 ` Andrew Morton
2006-06-23 22:07 ` Jay Lan
2006-06-23 23:47 ` Andrew Morton
2006-06-24 2:59 ` Shailabh Nagar
2006-06-24 4:39 ` Andrew Morton
2006-06-24 5:59 ` Shailabh Nagar
2006-06-26 17:33 ` Jay Lan
2006-06-26 17:52 ` Shailabh Nagar
2006-06-26 17:55 ` Andrew Morton
2006-06-26 18:00 ` Shailabh Nagar
2006-06-26 18:12 ` Andrew Morton
2006-06-26 18:26 ` Jay Lan
2006-06-26 18:39 ` Andrew Morton
2006-06-26 18:49 ` Shailabh Nagar
2006-06-26 19:00 ` Jay Lan
2006-06-28 21:30 ` Jay Lan
2006-06-28 21:53 ` Andrew Morton
2006-06-28 22:02 ` Jay Lan
2006-06-29 8:40 ` Paul Jackson
2006-06-29 12:30 ` Valdis.Kletnieks
2006-06-29 16:44 ` Paul Jackson
2006-06-29 18:01 ` Andrew Morton
2006-06-29 18:07 ` Paul Jackson
2006-06-29 18:26 ` Paul Jackson
2006-06-29 19:15 ` Shailabh Nagar
2006-06-29 19:41 ` Paul Jackson
2006-06-29 21:42 ` Shailabh Nagar
2006-06-29 21:54 ` Jay Lan
2006-06-29 22:09 ` Shailabh Nagar
2006-06-29 22:23 ` Paul Jackson
2006-06-30 0:15 ` Shailabh Nagar
2006-06-30 0:40 ` Paul Jackson
2006-06-30 1:00 ` Shailabh Nagar
2006-06-30 1:05 ` Paul Jackson
[not found] ` <44A46C6C.1090405@watson.ibm.com>
2006-06-30 0:38 ` Paul Jackson
2006-06-30 2:21 ` Paul Jackson
2006-06-30 2:46 ` Shailabh Nagar
2006-06-30 2:54 ` Paul Jackson
2006-06-30 3:02 ` Paul Jackson
2006-06-29 19:22 ` Shailabh Nagar
2006-06-29 19:10 ` Shailabh Nagar
2006-06-29 19:23 ` Paul Jackson
2006-06-29 19:33 ` Andrew Morton
2006-06-29 19:43 ` Shailabh Nagar
2006-06-29 20:00 ` Andrew Morton
2006-06-29 22:13 ` Shailabh Nagar
2006-06-29 23:00 ` jamal
2006-06-29 20:01 ` Shailabh Nagar
2006-06-29 21:22 ` Paul Jackson
2006-06-29 22:54 ` jamal
2006-06-30 0:38 ` Shailabh Nagar
2006-06-30 1:05 ` Andrew Morton
2006-06-30 1:11 ` Shailabh Nagar
2006-06-30 1:30 ` jamal
2006-06-30 3:01 ` Shailabh Nagar
2006-06-30 12:45 ` jamal
2006-06-30 2:25 ` Paul Jackson
2006-06-30 2:35 ` Andrew Morton
2006-06-30 2:43 ` Paul Jackson
2006-06-29 19:33 ` Jay Lan
2006-06-30 18:53 ` Shailabh Nagar
2006-06-30 19:10 ` Shailabh Nagar
2006-06-30 19:19 ` Shailabh Nagar
2006-06-30 20:19 ` jamal
2006-06-30 22:50 ` Andrew Morton
2006-07-01 2:20 ` Shailabh Nagar
2006-07-01 2:43 ` Andrew Morton
2006-07-01 3:37 ` Shailabh Nagar
2006-07-01 3:51 ` Andrew Morton
2006-07-03 21:11 ` Shailabh Nagar
2006-07-03 21:41 ` Andrew Morton
2006-07-04 0:13 ` Shailabh Nagar
2006-07-04 0:38 ` Andrew Morton
2006-07-04 20:19 ` Paul Jackson
2006-07-04 20:22 ` Paul Jackson
2006-07-04 0:54 ` Shailabh Nagar
2006-07-04 1:01 ` Andrew Morton
2006-07-04 13:05 ` jamal
2006-07-04 15:18 ` Shailabh Nagar
2006-07-04 16:37 ` Shailabh Nagar
2006-07-04 19:24 ` jamal
2006-07-05 14:09 ` Shailabh Nagar
2006-07-05 20:25 ` Chris Sturtivant
2006-07-05 20:32 ` Shailabh Nagar
2006-07-03 4:53 ` Paul Jackson
2006-07-03 15:02 ` Shailabh Nagar
2006-07-03 15:55 ` Paul Jackson
2006-07-03 16:31 ` Paul Jackson
2006-07-04 0:09 ` Shailabh Nagar [this message]
2006-07-04 19:59 ` Paul Jackson
2006-07-05 17:20 ` Jay Lan
2006-07-05 18:18 ` Shailabh Nagar
2006-06-30 22:56 ` Andrew Morton
2006-06-29 18:05 ` Nick Piggin
2006-06-29 12:42 ` Shailabh Nagar
2006-06-24 3:08 ` Shailabh Nagar
2006-06-21 20:38 ` Andrew Morton
2006-06-21 21:31 ` Shailabh Nagar
2006-06-21 21:45 ` Jay Lan
2006-06-21 21:54 ` Andrew Morton
2006-06-21 22:19 ` Jay Lan
2006-06-21 21:59 ` Shailabh Nagar
2006-06-09 15:55 ` Chris Sturtivant
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