| Message ID | 20190624053351.5217-1-christophe.jaillet@wanadoo.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | staging: bcm2835-camera: Avoid apotential sleep while holding a spin_lock | expand |
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 >
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
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) {
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(-)