[OpenWrt-Devel] Device tree issues with TL-WDR4900 (mpc85xx) and kernel 4.0.1
Wojciech.Dubowik at neratec.com
Thu May 7 09:00:27 EDT 2015
On 07/05/15 14:49, Felix Fietkau wrote:
> On 2015-05-07 08:01, Wojciech Dubowik wrote:
>> Try to boot with kernel locking enabled. I have seen jffs2 deadlocks on
>> readdir. As far as I remember
>> with this patch it went through but I don't know anymore whether I have
>> changed sth in config.
>> Have a look at (search engine...) [PATCH] fs: jffs2: Add setup code for
>> spi nor flash.
>> Even with this patch I got some possible dead lock warnings so it might
>> be just a partial cure. BTW it's
>> a bit scary for future use. Looks like jffs2 doesn't get enough care...
> I believe the locking issues are an overlayfs regression, maybe even
> the same one as this one (which I fixed years ago):
> I believe this is the cause of the regression:
> commit 49c21e1cacd74a8c83407c70ad860c994e606e25
> Author: Miklos Szeredi <mszeredi at suse.cz>
> Date: Sat Dec 13 00:59:42 2014 +0100
> ovl: check whiteout while reading directory
> Don't make a separate pass for checking whiteouts, since we can do it while
> reading the upper directory.
> This will make it easier to handle multiple layers.
> Signed-off-by: Miklos Szeredi <mszeredi at suse.cz>
> It probably happens like this:
> overlayfs does a readdir, in which jffs2 takes a lock.
> From within the readdir fill callback, it calls lookup_one_len, which
> ends up back in jffs2 and tries to take the same lock again.
> => deadlock.
This is exactly what I have seen. I have got deadlocks on readdir.
Unfortunately I don't have any logs saved...
> - Felix
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