lkml.org 
[lkml]   [2011]   [Apr]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v7] USB host: Fix lockdep warning in AMD PLL quirk
On Wed, 13 Apr 2011, Roedel, Joerg wrote:

> On Tue, Apr 12, 2011 at 06:59:27AM -0400, Sergei Shtylyov wrote:
> > On 12-04-2011 10:41, Roedel, Joerg wrote:
>
> > > + if (nb)
> > > + pci_dev_put(nb);
> > > + if (smbus)
> > > + pci_dev_put(amd_chipset.smbus_dev);
> >
> > Here it is. This pointer is NULL, it should be 'smbus' instead.
>
> Ok, this is fixed now too.
>
> From 7ee4b6274f5e4c1f238e9ff4faa0b9a43f5203e2 Mon Sep 17 00:00:00 2001
> From: Joerg Roedel <joerg.roedel@amd.com>
> Date: Wed, 6 Apr 2011 13:07:53 +0200
> Subject: [PATCH] USB host: Fix lockdep warning in AMD PLL quirk
>
> Booting latest kernel on my test machine produces a lockdep
> warning from the usb_amd_find_chipset_info() function:
>
> WARNING: at /data/lemmy/linux.trees.git/kernel/lockdep.c:2465 lockdep_trace_alloc+0x95/0xc2()
> Hardware name: Snook
> Modules linked in:
> Pid: 959, comm: work_for_cpu Not tainted 2.6.39-rc2+ #22
> Call Trace:
> [<ffffffff8103c0d4>] warn_slowpath_common+0x80/0x98
> [<ffffffff812387e6>] ? T.492+0x24/0x26
> [<ffffffff8103c101>] warn_slowpath_null+0x15/0x17
> [<ffffffff81068667>] lockdep_trace_alloc+0x95/0xc2
> [<ffffffff810ed9ac>] slab_pre_alloc_hook+0x18/0x3b
> [<ffffffff810ef227>] kmem_cache_alloc_trace+0x25/0xba
> [<ffffffff812387e6>] T.492+0x24/0x26
> [<ffffffff81238816>] pci_get_subsys+0x2e/0x73
> [<ffffffff8123886c>] pci_get_device+0x11/0x13
> [<ffffffff814082a9>] usb_amd_find_chipset_info+0x3f/0x18a
> ...
>
> It turns out that this function calls pci_get_device under a spin_lock
> with irqs disabled, but the pci_get_device function is only allowed in
> preemptible context.
>
> This patch fixes the warning by making all data-structure
> modifications on temporal storage and commiting this back
> into the visible structure at the end. While at it, this
> patch also moves the pci_dev_put calls out of the spinlocks
> because this function might sleep too.
>
> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

Acked-by: Alan Stern <stern@rowland.harvard.edu>



\
 
 \ /
  Last update: 2011-04-13 16:47    [W:0.073 / U:0.412 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site