* [PATCH] staging: bcm2835-camera: Avoid apotential sleep while holding a spin_lock
@ 2019-06-24 5:33 Christophe JAILLET
2019-06-24 6:37 ` Nicholas Mc Guire
2019-06-24 8:13 ` Stefan Wahren
0 siblings, 2 replies; 3+ messages in thread
From: Christophe JAILLET @ 2019-06-24 5:33 UTC (permalink / raw)
To: eric, stefan.wahren, gregkh, f.fainelli, rjui, sbranden,
bcm-kernel-feedback-list, tuomas.tynkkynen, inf.braun,
tobias.buettner, hofrat
Cc: devel, kernel-janitors, linux-kernel, Christophe JAILLET,
linux-rpi-kernel, linux-arm-kernel
Do not allocate memory with GFP_KERNEL when holding a spin_lock, it may
sleep. Use GFP_NOWAIT instead.
Fixes: 950fd867c635 ("staging: bcm2835-camera: Replace open-coded idr with a struct idr.")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
index 16af735af5c3..438d548c6e24 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
@@ -186,7 +186,7 @@ get_msg_context(struct vchiq_mmal_instance *instance)
*/
spin_lock(&instance->context_map_lock);
handle = idr_alloc(&instance->context_map, msg_context,
- 0, 0, GFP_KERNEL);
+ 0, 0, GFP_NOWAIT);
spin_unlock(&instance->context_map_lock);
if (handle < 0) {
--
2.20.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] staging: bcm2835-camera: Avoid apotential sleep while holding a spin_lock
2019-06-24 5:33 [PATCH] staging: bcm2835-camera: Avoid apotential sleep while holding a spin_lock Christophe JAILLET
@ 2019-06-24 6:37 ` Nicholas Mc Guire
2019-06-24 8:13 ` Stefan Wahren
1 sibling, 0 replies; 3+ messages in thread
From: Nicholas Mc Guire @ 2019-06-24 6:37 UTC (permalink / raw)
To: Christophe JAILLET
Cc: stefan.wahren, devel, f.fainelli, sbranden, tuomas.tynkkynen,
rjui, hofrat, kernel-janitors, linux-kernel, tobias.buettner,
eric, bcm-kernel-feedback-list, linux-rpi-kernel, gregkh,
inf.braun, linux-arm-kernel
On Mon, Jun 24, 2019 at 07:33:51AM +0200, Christophe JAILLET wrote:
> Do not allocate memory with GFP_KERNEL when holding a spin_lock, it may
> sleep. Use GFP_NOWAIT instead.
>
checking for this in the rest of the kernel with a cocci spatch
<snip>
virtual report
@nonatomic@
position p;
identifier var;
@@
spin_lock(...)
... when != spin_unlock(...)
* var = idr_alloc@p(...,GFP_KERNEL);
... when != spin_unlock(...)
spin_unlock(...);
<snip>
this seems to be the only instance of this specific problem.
> Fixes: 950fd867c635 ("staging: bcm2835-camera: Replace open-coded idr with a struct idr.")
The GFP_KERNEL actually was there befor this patch so not sure if this Fixes
ref is correct - I think the GFP_KERNEL was introduced in:
4e6bafdfb9f3 ("staging: bcm2835_camera: Use a mapping table for context field of mmal_msg_header")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Nicholas Mc Guire <hofrat@osadl.org>
> ---
> drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
> index 16af735af5c3..438d548c6e24 100644
> --- a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
> +++ b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
> @@ -186,7 +186,7 @@ get_msg_context(struct vchiq_mmal_instance *instance)
> */
> spin_lock(&instance->context_map_lock);
> handle = idr_alloc(&instance->context_map, msg_context,
> - 0, 0, GFP_KERNEL);
> + 0, 0, GFP_NOWAIT);
> spin_unlock(&instance->context_map_lock);
>
> if (handle < 0) {
> --
> 2.20.1
>
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] staging: bcm2835-camera: Avoid apotential sleep while holding a spin_lock
2019-06-24 5:33 [PATCH] staging: bcm2835-camera: Avoid apotential sleep while holding a spin_lock Christophe JAILLET
2019-06-24 6:37 ` Nicholas Mc Guire
@ 2019-06-24 8:13 ` Stefan Wahren
1 sibling, 0 replies; 3+ messages in thread
From: Stefan Wahren @ 2019-06-24 8:13 UTC (permalink / raw)
To: Christophe JAILLET, eric, gregkh, f.fainelli, rjui, sbranden,
bcm-kernel-feedback-list, tuomas.tynkkynen, inf.braun,
tobias.buettner, hofrat
Cc: devel, kernel-janitors, linux-kernel, linux-rpi-kernel,
Dave Stevenson, linux-arm-kernel
Hi Christophe,
Am 24.06.2019 um 07:33 schrieb Christophe JAILLET:
> Do not allocate memory with GFP_KERNEL when holding a spin_lock, it may
> sleep. Use GFP_NOWAIT instead.
>
> Fixes: 950fd867c635 ("staging: bcm2835-camera: Replace open-coded idr with a struct idr.")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
there has been a fix for this, which isn't upstreamed yet. The preferred
solution is to replace the spin_lock with a mutex. Since i'm currently
working on this i would take care of this.
Sorry about this.
Stefan
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2019-06-24 6:37 ` Nicholas Mc Guire
2019-06-24 8:13 ` Stefan Wahren
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