Please, ignore this patch. This patch has still some problems. I will post it later.
Thanks, Inki Dae > -----Original Message----- > From: Inki Dae [mailto:inki....@samsung.com] > Sent: Monday, September 23, 2013 7:43 PM > To: airl...@linux.ie; dri-devel@lists.freedesktop.org > Cc: Inki Dae; Kyungmin Park > Subject: [PATCH] drm/exynos: fix deadlock issue at mmap > > This patch fixes the deadlock issue when another process requested > mmap system call. > > This issue can incur the deadlock if another process sharing the same > file called mmap system call between ->f_op pointer chaning and restoring. > > So this patch calls down_write(&mm->mmap_sem) before do_mmap_pgoff > call and then up_write(&mm->mmap_sem) after do_mmap_pg_off call > so that when another process called mmap system call, the process > can wait for up_write() call until the ->f_op pointer is restored. > > Signed-off-by: Inki Dae <inki....@samsung.com> > Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com> > --- > drivers/gpu/drm/exynos/exynos_drm_gem.c | 20 ++++++++++++++++++-- > 1 file changed, 18 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c > b/drivers/gpu/drm/exynos/exynos_drm_gem.c > index 49f9cd2..779c2d7 100644 > --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c > +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c > @@ -13,6 +13,7 @@ > #include <drm/drm_vma_manager.h> > > #include <linux/shmem_fs.h> > +#include <linux/security.h> > #include <drm/exynos_drm.h> > > #include "exynos_drm_drv.h" > @@ -420,6 +421,7 @@ int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, > void *data, > { > struct drm_exynos_gem_mmap *args = data; > struct drm_gem_object *obj; > + struct mm_struct *mm = current->mm; > unsigned long addr; > > if (!(dev->driver->driver_features & DRIVER_GEM)) { > @@ -433,6 +435,8 @@ int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, > void *data, > return -EINVAL; > } > > + down_write(&mm->mmap_sem); > + > /* > * We have to use gem object and its fops for specific mmaper, > * but vm_mmap() can deliver only filp. So we have to change > @@ -457,8 +461,17 @@ int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, > void *data, > */ > file_priv->filp->private_data = obj; > > - addr = vm_mmap(file_priv->filp, 0, args->size, > - PROT_READ | PROT_WRITE, MAP_SHARED, 0); > + addr = security_mmap_file(file_priv->filp, PROT_READ | PROT_WRITE, > + MAP_SHARED); > + if (!addr) { > + unsigned long populate; > + > + addr = do_mmap_pgoff(file_priv->filp, 0, args->size, > + PROT_READ | PROT_WRITE, > + MAP_SHARED, 0, &populate); > + if (populate) > + mm_populate(addr, populate); > + } > > drm_gem_object_unreference(obj); > > @@ -469,10 +482,13 @@ int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, > void *data, > file_priv->filp->private_data = file_priv; > } > mutex_unlock(&dev->struct_mutex); > + up_write(&mm->mmap_sem); > + > return (int)addr; > } > > mutex_unlock(&dev->struct_mutex); > + up_write(&mm->mmap_sem); > > args->mapped = addr; > > -- > 1.7.9.5 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
