From: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
To: Willy Tarreau <w@1wt.eu>
Cc: Ben Hutchings <ben@decadent.org.uk>,
<linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>,
Pavel Roskin <proski@gnu.org>,
"John W. Linville" <linville@tuxdriver.com>
Subject: Re: [ 08/12] mac80211: zero initialize count field in ieee80211_tx_rate
Date: Mon, 12 Mar 2012 12:22:45 +0530 [thread overview]
Message-ID: <4F5D9D3D.6090206@qca.qualcomm.com> (raw)
In-Reply-To: <20120312063412.GD8971@1wt.eu>
Hi Willy,
> On Mon, Mar 12, 2012 at 10:06:23AM +0530, Mohammed Shafi Shajakhan wrote:
>>> So I'm pretty sure this patch is wrong for 2.6.32; it could be
>>> backported but I don't think the change is necessary anyway.
>>
>> true, but i think its better to initialize the count = 0 rather than
>> count = 1, though the older version driver checks for rate[i].idx>= 0
>> in ath_rc_tx_status. while the ath_tx_status has no such iteration in
>> the older driver code.
>
> In practice, if the patch brings nothing and not even correctness, I'd
> rather drop it than make us believe that some issue is fixed. However
> if you think it does happen to fix a real issue in 2.6.32 (possibly
> combined with some other missing patch), please tell me so and I will
> happily undelete it.
>
we can drop it. also as there was no driver code checking for
rate[i].count in the 2.6.32 driver. i am also not sure this fixes
something in 2.6.32 but the patch itself is correct.
Pavel fixed a rate control crash in ath9k because of invalid rate index
(-1) access. we were wondering how is it possible the driver can be
using a invalid rate index ?
we can simply rule out a rate is invalid checking for (rate[i].idx < 0
&& rate[i].count != 0)
Pavel found that the driver previously checks "only" for rate[i].count
as non-zero and this itself seems sufficient as we assumed the invalid
rate indexes are initialized with -1, 0 for rate[i].idx and
rate[i].count respectively. later found that mac80211 rate[i].count
initializes with '1' for the 'rate[i].count' field.
thus we generically fixed in mac80211(also as per doc) to avoid any such
issues in any rate control, though we can blame the driver for not
checking for invalid rate.idx while blindly believing on rate[i].count.
thank you!
--
thanks,
shafi
next prev parent reply other threads:[~2012-03-12 6:52 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <feb44625a10a45049eddf27890e95d54@local>
2012-03-12 0:20 ` [ 00/12] 2.6.32.59-longterm review Willy Tarreau
2012-03-12 0:20 ` [ 01/12] compat: Re-add missing asm/compat.h include to fix compile breakage on s390 Willy Tarreau
2012-03-12 0:20 ` [ 02/12] Remove COMPAT_IA32 support Willy Tarreau
2012-03-12 1:07 ` Ben Hutchings
2012-03-12 2:49 ` Greg KH
2012-03-12 6:30 ` Willy Tarreau
2012-03-12 6:48 ` stripping [PATCH] without losing later tags from mailed patches (Re: [ 02/12] Remove COMPAT_IA32 support) Jonathan Nieder
2012-03-12 8:58 ` Willy Tarreau
2012-03-12 15:20 ` Greg KH
2012-03-12 15:24 ` Willy Tarreau
2012-03-12 16:41 ` Thomas Rast
2012-03-12 16:53 ` Willy Tarreau
2012-03-12 16:57 ` Jonathan Nieder
2012-03-12 18:04 ` Junio C Hamano
2012-03-12 18:50 ` Willy Tarreau
2012-03-12 18:54 ` Jonathan Nieder
2012-03-12 19:17 ` Willy Tarreau
2012-03-12 21:47 ` Thomas Rast
2012-03-12 21:56 ` [PATCH] git-am: error out when seeing -b/--binary Jonathan Nieder
2012-03-12 22:03 ` Thomas Rast
2012-03-12 22:22 ` Jonathan Nieder
2012-03-13 15:31 ` Thomas Rast
2012-03-13 17:31 ` Junio C Hamano
2012-03-13 17:51 ` Jonathan Nieder
2012-03-13 18:22 ` Junio C Hamano
2012-03-12 22:12 ` Junio C Hamano
2012-03-12 21:57 ` stripping [PATCH] without losing later tags from mailed patches (Re: [ 02/12] Remove COMPAT_IA32 support) Junio C Hamano
2012-03-12 16:40 ` Junio C Hamano
2012-03-12 16:48 ` Willy Tarreau
2012-03-12 17:57 ` Junio C Hamano
2012-03-12 18:45 ` Willy Tarreau
2012-03-12 19:29 ` Junio C Hamano
2012-03-12 17:12 ` Greg KH
2012-03-12 18:01 ` Junio C Hamano
2012-03-12 19:26 ` Greg KH
2012-03-12 19:51 ` Junio C Hamano
2012-03-12 20:19 ` Willy Tarreau
2012-03-12 15:25 ` [ 02/12] Remove COMPAT_IA32 support Ben Hutchings
2012-03-12 17:02 ` Arnd Bergmann
2012-03-12 17:14 ` Willy Tarreau
2012-03-12 19:34 ` Ben Hutchings
2012-03-12 19:45 ` Willy Tarreau
2012-03-12 0:20 ` [ 03/12] writeback: fixups for !dirty_writeback_centisecs Willy Tarreau
2012-03-12 0:20 ` [ 04/12] bsg: fix sysfs link remove warning Willy Tarreau
2012-03-12 0:20 ` [ 05/12] eCryptfs: Handle failed metadata read in lookup Willy Tarreau
2012-03-12 0:20 ` [ 06/12] [S390] KEYS: Enable the compat keyctl wrapper on s390x Willy Tarreau
2012-03-12 0:20 ` [ 07/12] cifs: fix dentry refcount leak when opening a FIFO on lookup Willy Tarreau
2012-03-12 0:20 ` [ 08/12] mac80211: zero initialize count field in ieee80211_tx_rate Willy Tarreau
2012-03-12 1:57 ` Ben Hutchings
2012-03-12 4:36 ` Mohammed Shafi Shajakhan
2012-03-12 6:34 ` Willy Tarreau
2012-03-12 6:52 ` Mohammed Shafi Shajakhan [this message]
2012-03-12 15:23 ` Ben Hutchings
2012-03-12 15:55 ` Mohammed Shafi Shajakhan
2012-03-12 16:10 ` Mohammed Shafi Shajakhan
2012-03-12 6:31 ` Willy Tarreau
2012-03-12 0:20 ` [ 09/12] net/usbnet: avoid recursive locking in usbnet_stop() Willy Tarreau
2012-03-12 0:20 ` [ 10/12] regset: Prevent null pointer reference on readonly regsets Willy Tarreau
2012-03-12 0:20 ` [ 11/12] regset: Return -EFAULT, not -EIO, on host-side memory fault Willy Tarreau
2012-03-12 0:20 ` [ 12/12] watchdog: hpwdt: clean up set_memory_x call for 32 bit Willy Tarreau
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