2020-11-20 15:32:45

by Matti Hamalainen

[permalink] [raw]
Subject: [PATCH] drm/nouveau: fix relocations applying logic and a double-free

Commit 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl") included
a logic-bug which results in the relocations not actually getting
applied at all as the call to nouveau_gem_pushbuf_reloc_apply() is
never reached. This causes a regression with graphical corruption,
triggered when relocations need to be done (for example after a
suspend/resume cycle.)

Fix by setting *apply_relocs value only if there were more than 0
relocations.

Additionally, the never reached code had a leftover u_free() call,
which, after fixing the logic, now got called and resulted in a
double-free. Fix by removing one u_free(), moving the other
and adding check for errors.

Cc: Daniel Vetter <[email protected]>
Cc: Ben Skeggs <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Matti Hamalainen <[email protected]>
Fixes: 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl")
Link: https://gitlab.freedesktop.org/drm/nouveau/-/issues/11
---
drivers/gpu/drm/nouveau/nouveau_gem.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 549bc67feabb..c2051380d18c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -558,8 +558,10 @@ nouveau_gem_pushbuf_validate(struct nouveau_channel *chan,
NV_PRINTK(err, cli, "validating bo list\n");
validate_fini(op, chan, NULL, NULL);
return ret;
+ } else if (ret > 0) {
+ *apply_relocs = true;
}
- *apply_relocs = ret;
+
return 0;
}

@@ -662,7 +664,6 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
nouveau_bo_wr32(nvbo, r->reloc_bo_offset >> 2, data);
}

- u_free(reloc);
return ret;
}

@@ -872,9 +873,10 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void *data,
break;
}
}
- u_free(reloc);
}
out_prevalid:
+ if (!IS_ERR(reloc))
+ u_free(reloc);
u_free(bo);
u_free(push);


base-commit: 3494d58865ad4a47611dbb427b214cc5227fa5eb
--
2.29.2


2020-11-23 09:54:37

by Daniel Vetter

[permalink] [raw]
Subject: Re: [PATCH] drm/nouveau: fix relocations applying logic and a double-free

On Fri, Nov 20, 2020 at 4:23 PM Matti Hamalainen <[email protected]> wrote:
>
> Commit 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl") included
> a logic-bug which results in the relocations not actually getting
> applied at all as the call to nouveau_gem_pushbuf_reloc_apply() is
> never reached. This causes a regression with graphical corruption,
> triggered when relocations need to be done (for example after a
> suspend/resume cycle.)
>
> Fix by setting *apply_relocs value only if there were more than 0
> relocations.
>
> Additionally, the never reached code had a leftover u_free() call,
> which, after fixing the logic, now got called and resulted in a
> double-free. Fix by removing one u_free(), moving the other
> and adding check for errors.
>
> Cc: Daniel Vetter <[email protected]>
> Cc: Ben Skeggs <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Matti Hamalainen <[email protected]>
> Fixes: 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl")
> Link: https://gitlab.freedesktop.org/drm/nouveau/-/issues/11

Link: is for the mailing list submission of the patch itself (to link
the git log to the mailing list discussions), this should be
References: or similar. Aside from this:

Reviewed-by: Daniel Vetter <[email protected]>

Ben, I'm assuming you'll push this through your tree.
-Daniel


> ---
> drivers/gpu/drm/nouveau/nouveau_gem.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
> index 549bc67feabb..c2051380d18c 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_gem.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
> @@ -558,8 +558,10 @@ nouveau_gem_pushbuf_validate(struct nouveau_channel *chan,
> NV_PRINTK(err, cli, "validating bo list\n");
> validate_fini(op, chan, NULL, NULL);
> return ret;
> + } else if (ret > 0) {
> + *apply_relocs = true;
> }
> - *apply_relocs = ret;
> +
> return 0;
> }
>
> @@ -662,7 +664,6 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
> nouveau_bo_wr32(nvbo, r->reloc_bo_offset >> 2, data);
> }
>
> - u_free(reloc);
> return ret;
> }
>
> @@ -872,9 +873,10 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void *data,
> break;
> }
> }
> - u_free(reloc);
> }
> out_prevalid:
> + if (!IS_ERR(reloc))
> + u_free(reloc);
> u_free(bo);
> u_free(push);
>
>
> base-commit: 3494d58865ad4a47611dbb427b214cc5227fa5eb
> --
> 2.29.2
>


--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

2020-11-26 10:13:27

by Daniel Vetter

[permalink] [raw]
Subject: Re: [PATCH] drm/nouveau: fix relocations applying logic and a double-free

On Mon, Nov 23, 2020 at 10:51:25AM +0100, Daniel Vetter wrote:
> On Fri, Nov 20, 2020 at 4:23 PM Matti Hamalainen <[email protected]> wrote:
> >
> > Commit 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl") included
> > a logic-bug which results in the relocations not actually getting
> > applied at all as the call to nouveau_gem_pushbuf_reloc_apply() is
> > never reached. This causes a regression with graphical corruption,
> > triggered when relocations need to be done (for example after a
> > suspend/resume cycle.)
> >
> > Fix by setting *apply_relocs value only if there were more than 0
> > relocations.
> >
> > Additionally, the never reached code had a leftover u_free() call,
> > which, after fixing the logic, now got called and resulted in a
> > double-free. Fix by removing one u_free(), moving the other
> > and adding check for errors.
> >
> > Cc: Daniel Vetter <[email protected]>
> > Cc: Ben Skeggs <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Matti Hamalainen <[email protected]>
> > Fixes: 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl")
> > Link: https://gitlab.freedesktop.org/drm/nouveau/-/issues/11
>
> Link: is for the mailing list submission of the patch itself (to link
> the git log to the mailing list discussions), this should be
> References: or similar. Aside from this:
>
> Reviewed-by: Daniel Vetter <[email protected]>
>
> Ben, I'm assuming you'll push this through your tree.

Ok Dave asked me to just push it into drm-misc-fixes.

Thanks for your patch!
-Daniel

> -Daniel
>
>
> > ---
> > drivers/gpu/drm/nouveau/nouveau_gem.c | 8 +++++---
> > 1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
> > index 549bc67feabb..c2051380d18c 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_gem.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
> > @@ -558,8 +558,10 @@ nouveau_gem_pushbuf_validate(struct nouveau_channel *chan,
> > NV_PRINTK(err, cli, "validating bo list\n");
> > validate_fini(op, chan, NULL, NULL);
> > return ret;
> > + } else if (ret > 0) {
> > + *apply_relocs = true;
> > }
> > - *apply_relocs = ret;
> > +
> > return 0;
> > }
> >
> > @@ -662,7 +664,6 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
> > nouveau_bo_wr32(nvbo, r->reloc_bo_offset >> 2, data);
> > }
> >
> > - u_free(reloc);
> > return ret;
> > }
> >
> > @@ -872,9 +873,10 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void *data,
> > break;
> > }
> > }
> > - u_free(reloc);
> > }
> > out_prevalid:
> > + if (!IS_ERR(reloc))
> > + u_free(reloc);
> > u_free(bo);
> > u_free(push);
> >
> >
> > base-commit: 3494d58865ad4a47611dbb427b214cc5227fa5eb
> > --
> > 2.29.2
> >
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch