lkml.org 
[lkml]   [2020]   [Jan]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2 13/24] drm/etnaviv: reject timeouts with tv_nsec >= NSEC_PER_SEC
From
Date
On Fr, 2020-01-17 at 16:47 +0100, Guido Günther wrote:
> Hi,
> On Fri, Dec 13, 2019 at 09:53:41PM +0100, Arnd Bergmann wrote:
> > Most kernel interfaces that take a timespec require normalized
> > representation with tv_nsec between 0 and NSEC_PER_SEC.
> >
> > Passing values larger than 0x100000000ull further behaves differently
> > on 32-bit and 64-bit kernels, and can cause the latter to spend a long
> > time counting seconds in timespec64_sub()/set_normalized_timespec64().
> >
> > Reject those large values at the user interface to enforce sane and
> > portable behavior.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > drivers/gpu/drm/etnaviv/etnaviv_drv.c | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> > index 1f9c01be40d7..95d72dc00280 100644
> > --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> > +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> > @@ -297,6 +297,9 @@ static int etnaviv_ioctl_gem_cpu_prep(struct drm_device *dev, void *data,
> > if (args->op & ~(ETNA_PREP_READ | ETNA_PREP_WRITE | ETNA_PREP_NOSYNC))
> > return -EINVAL;
> >
> > + if (args->timeout.tv_nsec > NSEC_PER_SEC)
> > + return -EINVAL;
> > +
> > obj = drm_gem_object_lookup(file, args->handle);
> > if (!obj)
> > return -ENOENT;
> > @@ -360,6 +363,9 @@ static int etnaviv_ioctl_wait_fence(struct drm_device *dev, void *data,
> > if (args->flags & ~(ETNA_WAIT_NONBLOCK))
> > return -EINVAL;
> >
> > + if (args->timeout.tv_nsec > NSEC_PER_SEC)
> > + return -EINVAL;
> > +
> > if (args->pipe >= ETNA_MAX_PIPES)
> > return -EINVAL;
> >
> > @@ -411,6 +417,9 @@ static int etnaviv_ioctl_gem_wait(struct drm_device *dev, void *data,
> > if (args->flags & ~(ETNA_WAIT_NONBLOCK))
> > return -EINVAL;
> >
> > + if (args->timeout.tv_nsec > NSEC_PER_SEC)
> > + return -EINVAL;
> > +
> > if (args->pipe >= ETNA_MAX_PIPES)
> > return -EINVAL;
> >
>
> This breaks rendering here on arm64/gc7000 due to
>
> ioctl(6, DRM_IOCTL_ETNAVIV_GEM_CPU_PREP or DRM_IOCTL_MSM_GEM_CPU_PREP, 0xfffff7888680) = -1 EINVAL (Invalid argument)
> ioctl(6, DRM_IOCTL_ETNAVIV_GEM_CPU_FINI or DRM_IOCTL_QXL_CLIENTCAP, 0xfffff78885e0) = 0
> ioctl(6, DRM_IOCTL_ETNAVIV_GEM_CPU_PREP or DRM_IOCTL_MSM_GEM_CPU_PREP, 0xfffff7888680) = -1 EINVAL (Invalid argument)
> ioctl(6, DRM_IOCTL_ETNAVIV_GEM_CPU_FINI or DRM_IOCTL_QXL_CLIENTCAP, 0xfffff78885e0) = 0
> ioctl(6, DRM_IOCTL_ETNAVIV_GEM_CPU_PREP or DRM_IOCTL_MSM_GEM_CPU_PREP, 0xfffff7888680) = -1 EINVAL (Invalid argument)
> ioctl(6, DRM_IOCTL_ETNAVIV_GEM_CPU_FINI or DRM_IOCTL_QXL_CLIENTCAP, 0xfffff78885e0) = 0
>
> This is due to
>
> get_abs_timeout(&req.timeout, 5000000000);
>
> in etna_bo_cpu_prep which can exceed NSEC_PER_SEC.
>
> Should i send a patch to revert that change since it breaks existing userspace?

No need to revert. This patch has not been applied to the etnaviv tree
yet, I guess it's just in one of Arnds branches feeding into -next.

That part of userspace is pretty dumb, as it misses to renormalize
tv_nsec when it overflows the second boundary. So if what I see is
correct it should be enough to allow 2 * NSEC_PER_SEC, which should
both reject broken large timeout and keep existing userspace working.

Regards,
Lucas

\
 
 \ /
  Last update: 2020-01-20 18:48    [W:0.061 / U:5.664 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site