From: Pavel Roskin <proski@gnu.org>
To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: linux-wireless@vger.kernel.org,
"John W. Linville" <linville@tuxdriver.com>
Subject: Re: [PATCH] mac80211: use BUG_ON and return -EINVAL if rate_lowest_index() fails
Date: Thu, 16 Jun 2011 18:08:31 -0400 [thread overview]
Message-ID: <4DFA7EDF.70608@gnu.org> (raw)
In-Reply-To: <20110616102224.GB2178@redhat.com>
On 06/16/2011 06:22 AM, Stanislaw Gruszka wrote:
> Hi Pavel
>
> On Wed, Jun 15, 2011 at 06:02:52PM -0400, Pavel Roskin wrote:
>> WARN_ON is not enough, as we cannot return a valid index, and the
>> callers will use whatever we return, causing a cascade of oopses and
>> eventually a panic.
>
> We have fedora bug (https://bugzilla.redhat.com/show_bug.cgi?id=702627)
> where only that warning is generated, and system works further (at least
> bug reporter did not mention about it's hang). When moving to BUG(),
> system from user perspective will simply hang, what is much worse.
> I think, we should rather fix callers to be prepared and recover itself
> when rate_lowest_index fail. Of course fixing real bug(s) that cause
> rate index is not found would be best.
In my case, I was able to restart the system by sysrq when using BUG_ON,
but the system would hang hard with WARN_ON. I think continuing after
returning an invalid index is wrong. It will lead to memory corruption
that could in turn lead to corruption of the filesystem.
--
Regards,
Pavel Roskin
next prev parent reply other threads:[~2011-06-16 22:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-15 22:02 [PATCH] mac80211: use BUG_ON and return -EINVAL if rate_lowest_index() fails Pavel Roskin
2011-06-16 9:08 ` Arend van Spriel
2011-06-16 22:06 ` Pavel Roskin
2011-06-16 10:22 ` Stanislaw Gruszka
2011-06-16 22:08 ` Pavel Roskin [this message]
2011-06-17 6:37 ` Arend van Spriel
2011-06-17 20:33 ` Pavel Roskin
2011-06-19 8:05 ` Johannes Berg
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