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 <[email protected]>
---
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;
--
2.20.0
On Fri, 2019-12-13 at 21:53 +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 <[email protected]>
> ---
> 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)
[...]
There's an off-by-one error between the subject line and the actual
changes. The subject line seems to have the correct comparison.
Ben.
--
Ben Hutchings, Software Developer Codethink Ltd
https://www.codethink.co.uk/ Dale House, 35 Dale Street
Manchester, M1 2HF, United Kingdom
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 <[email protected]>
> ---
> 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?
Cheers,
-- Guido
> --
> 2.20.0
>
> _______________________________________________
> etnaviv mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/etnaviv
>
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 <[email protected]>
> > ---
> > 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
On Mon, Jan 20, 2020 at 6:48 PM Lucas Stach <[email protected]> wrote:
> On Fr, 2020-01-17 at 16:47 +0100, Guido Günther wrote:
> >
> > 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.
Ah, so it's never more than 2 billion nanoseconds in known user space?
I can definitely change my patch (actually add one on top) to allow that
and handle it as before, or alternatively accept any 64-bit nanosecond value
as arm64 already did, but make it less inefficient to handle.
Arnd
On Mo, 2020-01-20 at 19:47 +0100, Arnd Bergmann wrote:
> On Mon, Jan 20, 2020 at 6:48 PM Lucas Stach <[email protected]> wrote:
> > On Fr, 2020-01-17 at 16:47 +0100, Guido Günther wrote:
> > > 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.
>
> Ah, so it's never more than 2 billion nanoseconds in known user space?
> I can definitely change my patch (actually add one on top) to allow that
> and handle it as before, or alternatively accept any 64-bit nanosecond value
> as arm64 already did, but make it less inefficient to handle.
So the broken userspace code looks like this:
static inline void get_abs_timeout(struct drm_etnaviv_timespec *tv, uint64_t ns)
{
struct timespec t;
uint32_t s = ns / 1000000000;
clock_gettime(CLOCK_MONOTONIC, &t);
tv->tv_sec = t.tv_sec + s;
tv->tv_nsec = t.tv_nsec + ns - (s * 1000000000);
}
Which means it _tries_ to do the right thing by putting the billion
part into the tv_sec member and only the remaining ns part is added to
tv_nsec, but then it fails to propagate a tv_nsec overflow over
NSEC_PER_SEC into tv_sec.
Which means the tv_nsec should never be more than 2 * NSEC_PER_SEC in
known userspace. I would prefer if we could make the interface as
strict as possible (i.e. no arbitrary large numbers in tv_nsec), while
keeping this specific corner case working.
Regards,
Lucas
On Tue, Jan 21, 2020 at 11:22 AM Lucas Stach <[email protected]> wrote:
>
> On Mo, 2020-01-20 at 19:47 +0100, Arnd Bergmann wrote:
> > On Mon, Jan 20, 2020 at 6:48 PM Lucas Stach <[email protected]> wrote:
> > > On Fr, 2020-01-17 at 16:47 +0100, Guido Günther wrote:
> > > > 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.
> >
> > Ah, so it's never more than 2 billion nanoseconds in known user space?
> > I can definitely change my patch (actually add one on top) to allow that
> > and handle it as before, or alternatively accept any 64-bit nanosecond value
> > as arm64 already did, but make it less inefficient to handle.
>
> So the broken userspace code looks like this:
>
> static inline void get_abs_timeout(struct drm_etnaviv_timespec *tv, uint64_t ns)
> {
> struct timespec t;
> uint32_t s = ns / 1000000000;
> clock_gettime(CLOCK_MONOTONIC, &t);
> tv->tv_sec = t.tv_sec + s;
> tv->tv_nsec = t.tv_nsec + ns - (s * 1000000000);
> }
>
> Which means it _tries_ to do the right thing by putting the billion
> part into the tv_sec member and only the remaining ns part is added to
> tv_nsec, but then it fails to propagate a tv_nsec overflow over
> NSEC_PER_SEC into tv_sec.
>
> Which means the tv_nsec should never be more than 2 * NSEC_PER_SEC in
> known userspace. I would prefer if we could make the interface as
> strict as possible (i.e. no arbitrary large numbers in tv_nsec), while
> keeping this specific corner case working.
I've added a patch on top of my 2038 branch, please have a look at that.
Arnd