From: gregory.clement@free-electrons•com (Gregory CLEMENT)
To: linux-arm-kernel@lists•infradead.org
Subject: 3.16rc3 multiplatform, Armada 370 and IOMMU: unbootable kernel
Date: Thu, 03 Jul 2014 22:57:38 +0200 [thread overview]
Message-ID: <53B5C3C2.6080501@free-electrons.com> (raw)
In-Reply-To: <20140703225244.50378fa4@free-electrons.com>
Hi Thomas,
> Thanks for reproducing the problem. In my opinion, the problem is in
> drivers/iommu/omap-iommu.c, which gets compiled when
> CONFIG_OMAP_IOMMU=y. This file does:
>
I was also looking at it
> static int __init omap_iommu_init(void)
> {
> struct kmem_cache *p;
> const unsigned long flags = SLAB_HWCACHE_ALIGN;
> size_t align = 1 << 10; /* L2 pagetable alignement */
>
> p = kmem_cache_create("iopte_cache", IOPTE_TABLE_SIZE, align, flags,
> iopte_cachep_ctor);
> if (!p)
> return -ENOMEM;
> iopte_cachep = p;
>
> bus_set_iommu(&platform_bus_type, &omap_iommu_ops);
>
> return platform_driver_register(&omap_iommu_driver);
> }
> /* must be ready before omap3isp is probed */
> subsys_initcall(omap_iommu_init);
>
> So it calls bus_set_iommu() unconditionally, without caring at all
> whether it is running on a platform that actually cares about OMAP
> IOMMU. And then later on, a bus notifier of the IOMMU subsystem gets
> called, and some NULL pointer gets dereferenced. I'm pretty sure that
> if you comment out this subsys_initcall(), you won't see the problem
> anymore.
Indeed I comment it, and I didn't see the problem anymore.
>
> However, this code has been around since a while, so I don't know if
> it's actually the change that makes it visible. Maybe some other IOMMU
> core internal change makes it actually visible. But this
> subsys_initcall() that does random stuff without caring about the
> platform it runs on anyway looks incorrect.
I think that nobody until now have run this configuration.
Thanks,
Gregory
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
next prev parent reply other threads:[~2014-07-03 20:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-03 13:51 3.16rc3 multiplatform, Armada 370 and IOMMU: unbootable kernel Paolo Pisati
2014-07-03 14:27 ` Thomas Petazzoni
2014-07-03 14:57 ` Paolo Pisati
2014-07-03 20:22 ` Gregory CLEMENT
2014-07-03 20:52 ` Thomas Petazzoni
2014-07-03 20:57 ` Gregory CLEMENT [this message]
2014-07-03 21:01 ` Thomas Petazzoni
2014-07-03 21:07 ` Gregory CLEMENT
2014-07-03 21:24 ` Gregory CLEMENT
2014-07-04 8:47 ` Laurent Pinchart
2014-07-05 15:03 ` Ezequiel Garcia
2014-07-05 20:59 ` Greg Kroah-Hartman
2014-07-07 10:58 ` Ezequiel Garcia
2014-07-07 18:30 ` Greg Kroah-Hartman
2014-07-07 23:37 ` Ezequiel Garcia
2014-07-07 23:47 ` Greg Kroah-Hartman
2014-07-08 7:41 ` Thomas Petazzoni
2014-07-08 9:20 ` Paolo Pisati
2014-07-08 12:01 ` Jason Cooper
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=53B5C3C2.6080501@free-electrons.com \
--to=gregory.clement@free-electrons$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox