On Saturday 15 May 2010, mgross wrote:
> On Sat, May 15, 2010 at 09:38:47PM +0200, Rafael J. Wysocki wrote:
> > On Saturday 15 May 2010, mgross wrote:
> > > I apologize for the goofy email address.
> > >
> > > The following is a fix for the crash reported by Valdis.
> > >
> > > The problem was that the original pm_qos silently fails when a request
> > > update is passed to a parameter that has not been added to the list
> > > yet. It seems that the e1000e is doing this. This update restores this
> > > behavior.
> > >
> > > I need to think about how to better handle such abuse, but for now this
> > > restores the original behavior.
> >
> > Can you please post a signed-off incremental patch against
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6.git for-llinus
> >
> > that contains your original PM QOS update?
>
> No problem:
>
> Signed-off-by: markgross <markgross@xxxxxxxxxxx>
Thanks! Do you want to use this address for the sign-off or the Intel one?
Rafael
> From 487b8dcaeb66d3c226d4c06c1bd99689f93024be Mon Sep 17 00:00:00 2001
> From: mgross <mgross@mgross-desktop.(none)>
> Date: Sat, 15 May 2010 14:30:15 -0700
> Subject: [PATCH] Gard against pm_qos users calling API before registering a proper
> request.
>
> This update handles a use case where pm_qos update requests need to
> silently fail if the update is being sent to a handle that is null.
>
> The problem was that the original pm_qos silently fails when a request
> update is passed to a parameter that has not been added to the list yet.
> This update restores that behavior.
>
> Signed-off-by: markgross <markgross@xxxxxxxxxxx>
>
> ---
> kernel/pm_qos_params.c | 26 ++++++++++++++------------
> 1 files changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
> index a1aea04..f42d3f7 100644
> --- a/kernel/pm_qos_params.c
> +++ b/kernel/pm_qos_params.c
> @@ -252,19 +252,21 @@ void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
> int pending_update = 0;
> s32 temp;
>
> - spin_lock_irqsave(&pm_qos_lock, flags);
> - if (new_value == PM_QOS_DEFAULT_VALUE)
> - temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
> - else
> - temp = new_value;
> -
> - if (temp != pm_qos_req->value) {
> - pending_update = 1;
> - pm_qos_req->value = temp;
> + if (pm_qos_req) { /*guard against callers passing in null */
> + spin_lock_irqsave(&pm_qos_lock, flags);
> + if (new_value == PM_QOS_DEFAULT_VALUE)
> + temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
> + else
> + temp = new_value;
> +
> + if (temp != pm_qos_req->value) {
> + pending_update = 1;
> + pm_qos_req->value = temp;
> + }
> + spin_unlock_irqrestore(&pm_qos_lock, flags);
> + if (pending_update)
> + update_target(pm_qos_req->pm_qos_class);
> }
> - spin_unlock_irqrestore(&pm_qos_lock, flags);
> - if (pending_update)
> - update_target(pm_qos_req->pm_qos_class);
> }
> EXPORT_SYMBOL_GPL(pm_qos_update_request);
>
>
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