* [PATCH] devres: WARN() and return, don't crash on device_del() of uninitialized device
@ 2009-05-25 6:53 Benjamin Herrenschmidt
2009-05-26 21:15 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Benjamin Herrenschmidt @ 2009-05-25 6:53 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, Greg Kroah-Hartman
I just debugged an obscure crash caused by a device_del() of a all NULL'd
out struct device (in usb-serial) and found that a patch like this one would
have saved me time (in addition to improved chances of a bug report from
users hitting similar driver bugs).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
drivers/base/devres.c | 5 +++++
1 file changed, 5 insertions(+)
--- linux-work.orig/drivers/base/devres.c 2009-05-25 16:43:46.000000000 +1000
+++ linux-work/drivers/base/devres.c 2009-05-25 16:46:36.000000000 +1000
@@ -428,6 +428,11 @@ int devres_release_all(struct device *de
{
unsigned long flags;
+ /* Looks like an uninitialized device structure */
+ if (dev->devres_head.next == NULL) {
+ WARN(1);
+ return -ENODEV;
+ }
spin_lock_irqsave(&dev->devres_lock, flags);
return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
flags);
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] devres: WARN() and return, don't crash on device_del() of uninitialized device
2009-05-25 6:53 [PATCH] devres: WARN() and return, don't crash on device_del() of uninitialized device Benjamin Herrenschmidt
@ 2009-05-26 21:15 ` Andrew Morton
2009-05-26 22:23 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2009-05-26 21:15 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linux-kernel, greg, Kay Sievers, Tejun Heo
On Mon, 25 May 2009 16:53:31 +1000
Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> I just debugged an obscure crash caused by a device_del() of a all NULL'd
> out struct device (in usb-serial) and found that a patch like this one would
> have saved me time (in addition to improved chances of a bug report from
> users hitting similar driver bugs).
>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> ---
>
> drivers/base/devres.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> --- linux-work.orig/drivers/base/devres.c 2009-05-25 16:43:46.000000000 +1000
> +++ linux-work/drivers/base/devres.c 2009-05-25 16:46:36.000000000 +1000
> @@ -428,6 +428,11 @@ int devres_release_all(struct device *de
> {
> unsigned long flags;
>
> + /* Looks like an uninitialized device structure */
> + if (dev->devres_head.next == NULL) {
> + WARN(1);
> + return -ENODEV;
> + }
> spin_lock_irqsave(&dev->devres_lock, flags);
> return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
> flags);
This could be coded a little more neatly as:
/* Looks like an uninitialized device structure */
if (WARN_ON(dev->devres_head.next == NULL))
return -ENODEV;
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] devres: WARN() and return, don't crash on device_del() of uninitialized device
2009-05-26 21:15 ` Andrew Morton
@ 2009-05-26 22:23 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 3+ messages in thread
From: Benjamin Herrenschmidt @ 2009-05-26 22:23 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, greg, Kay Sievers, Tejun Heo
On Tue, 2009-05-26 at 14:15 -0700, Andrew Morton wrote:
>
> This could be coded a little more neatly as:
>
> /* Looks like an uninitialized device structure */
> if (WARN_ON(dev->devres_head.next == NULL))
> return -ENODEV;
Oh I didn't know we could do that nowadays...
Cheers,
Ben.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2009-05-26 22:26 UTC | newest]
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2009-05-25 6:53 [PATCH] devres: WARN() and return, don't crash on device_del() of uninitialized device Benjamin Herrenschmidt
2009-05-26 21:15 ` Andrew Morton
2009-05-26 22:23 ` Benjamin Herrenschmidt
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