lkml.org 
[lkml]   [2011]   [Dec]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Massive log spam loading modules on ARM after 3.2-rc5 (regression)
On Wed, Dec 14, 2011 at 04:51:33PM -0500, Nick Bowler wrote:
> Hi folks,
>
> With latest Linus' master, I'm faced with massive log spam on our ARM
> Versatile Express platform when using modules. Here's an example:
>
> # modprobe sp805-wdt
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> sp805-wdt mb:wdt: registration successful
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
> unwind: Unknown symbol address 7f802009
> unwind: Index not found 7f802009
>
> The message only seem to get printed at module load time. Other than
> the noise, things _seem_ to be working. Nevertheless, it's a regression
> introduced after 3.2-rc5 by the following commit:
>
> de66a979012dbc66b1ec0125795a3f79ee667b8a is the first bad commit
> commit de66a979012dbc66b1ec0125795a3f79ee667b8a
> Author: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> Date: Mon Dec 5 09:39:59 2011 +0100
>
> ARM: 7187/1: fix unwinding for XIP kernels
>
> The linker places the unwind tables in readonly sections. So when using
> an XIP kernel these are located in ROM and cannot be modified.
> For that reason the current approach to convert the relative offsets in
> the unwind index to absolute addresses early in the boot process doesn't
> work with XIP.
>
> The offsets in the unwind index section are signed 31 bit numbers and
> the structs are sorted by this offset. So it first has offsets between
> 0x40000000 and 0x7fffffff (i.e. the negative offsets) and then offsets
> between 0x00000000 and 0x3fffffff. When seperating these two blocks the
> numbers are sorted even when interpreting the offsets as unsigned longs.
>
> So determine the first non-negative entry once and track that using the
> new origin pointer. The actual bisection can then use a plain unsigned
> long comparison. The only thing that makes the new bisection more
> complicated is that the offsets are relative to their position in the
> index section, so the key to search needs to be adapted accordingly in
> each step.
>
> Moreover several consts are added to catch future writes and rename the
> member "addr" of struct unwind_idx to "addr_offset" to better match the
> new semantic. (This has the additional benefit of breaking eventual
> users at compile time to make them aware of the change.)
>
> In my tests the new algorithm was a tad faster than the original and has
> the additional upside of not needing the initial conversion and so saves
> some boot time and it's possible to unwind even earlier.
>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Acked-by: Nicolas Pitre <nico@fluxnic.net>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
>
> :040000 040000 9c4363228515808d71dac84a4a16e0aa0cf4ceaa 65b80d4e51fabf0a3142a880be795f4b38f4d9fe M arch
>
> I am *not* using XIP. Reverting this commit resolves the issue.
>
> Let me know if you need any more info,
Can you provide me your .config please? I cannot reproduce your problems
with modprobe on an i.MX28 based tx28 machine.

Russell, maybe this makes you a bit less annoyed?

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2011-12-15 10:29    [W:0.043 / U:0.664 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site