From: Pavel Roskin <proski@gnu.org>
To: Golden <goldenstranger@yahoo.com>
Cc: linux-wireless@vger.kernel.org
Subject: Re: firmware_loading_store: vmap() failed, broken firmware with kernles .27 - .30
Date: Tue, 30 Mar 2010 23:15:52 -0400 [thread overview]
Message-ID: <1270005352.27938.14.camel@mj> (raw)
In-Reply-To: <733969.9491.qm@web56807.mail.re3.yahoo.com>
On Thu, 2010-03-25 at 09:20 -0700, Golden wrote:
> Recent compat-wireless releases break firmware loading under slightly
> older kernels. The bug occurs as tested by me with 2.6.27 and 2.6.30,
> it does not appear on kernels 2.6.31 and up.
...
> b43 ssb0:0: firmware: requesting b43-open/ucode5.fw
> compat_firmware ssb0:0: firmware_loading_store: unexpected value (0)
I was able to reproduce "unexpected value" with Linux 2.6.28.10 and
ar9170usb.
After adding some debug printk's, I get this:
firmware_loading_store: loading = 1
firmware_loading_store: loading = 1
firmware_loading_store: loading = 0
fw_priv->fw->data = ffffc2001027a000
firmware_loading_store: loading = 0
compat_firmware 1-7: firmware_loading_store: unexpected value (0)
firmware_loading_store: abort
usb 1-7: ar9170.fw firmware file not found, trying old firmware...
It looks like we have a race condition here. Two processes try to load
the firmware.
I remember vaguely that it was discussed before. Google search for
"firmware_loading_store race" finds some interesting links, but I cannot
find a fix. Likewise, search for "firmware_loading_store: unexpected
value" finds a lot of stuff in the Linux 2.6.13 timeframe.
It looks like a race condition. Adding dump_stack() to the beginning of
firmware_loading_store() makes the problem disappear.
--
Regards,
Pavel Roskin
next prev parent reply other threads:[~2010-03-31 3:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-25 16:20 firmware_loading_store: vmap() failed, broken firmware with kernles .27 - .30 Golden
2010-03-27 12:22 ` Golden
2010-03-31 3:15 ` Pavel Roskin [this message]
2010-03-31 21:56 ` Golden
2010-04-02 1:53 ` Pavel Roskin
-- strict thread matches above, loose matches on Subject: below --
2010-04-02 6:42 Golden
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