* [PATCH] drm/bridge: megachips: Fix a null pointer dereference bug
@ 2022-07-16 8:13 Zheyu Ma
2022-07-19 8:38 ` Martyn Welch
2022-08-29 15:03 ` Robert Foss
0 siblings, 2 replies; 5+ messages in thread
From: Zheyu Ma @ 2022-07-16 8:13 UTC (permalink / raw)
To: peter.senna, martin.donnelly, martyn.welch, andrzej.hajda,
narmstrong, robert.foss, Laurent.pinchart, jonas, jernej.skrabec,
airlied, daniel
Cc: dri-devel, linux-kernel, Zheyu Ma
When removing the module we will get the following warning:
[ 31.911505] i2c-core: driver [stdp2690-ge-b850v3-fw] unregistered
[ 31.912484] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
[ 31.913338] KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
[ 31.915280] RIP: 0010:drm_bridge_remove+0x97/0x130
[ 31.921825] Call Trace:
[ 31.922533] stdp4028_ge_b850v3_fw_remove+0x34/0x60 [megachips_stdpxxxx_ge_b850v3_fw]
[ 31.923139] i2c_device_remove+0x181/0x1f0
The two bridges (stdp2690, stdp4028) do not probe at the same time, so
the driver does not call ge_b850v3_resgiter() when probing, causing the
driver to try to remove the object that has not been initialized.
Fix this by checking whether both the bridges are probed.
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
---
drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
index cce98bf2a4e7..c68a4cdf4625 100644
--- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
+++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
@@ -296,7 +296,9 @@ static void ge_b850v3_lvds_remove(void)
* This check is to avoid both the drivers
* removing the bridge in their remove() function
*/
- if (!ge_b850v3_lvds_ptr)
+ if (!ge_b850v3_lvds_ptr ||
+ !ge_b850v3_lvds_ptr->stdp2690_i2c ||
+ !ge_b850v3_lvds_ptr->stdp4028_i2c)
goto out;
drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] drm/bridge: megachips: Fix a null pointer dereference bug
2022-07-16 8:13 [PATCH] drm/bridge: megachips: Fix a null pointer dereference bug Zheyu Ma
@ 2022-07-19 8:38 ` Martyn Welch
2022-08-02 12:04 ` Ian Ray
2022-08-29 15:03 ` Robert Foss
1 sibling, 1 reply; 5+ messages in thread
From: Martyn Welch @ 2022-07-19 8:38 UTC (permalink / raw)
To: Zheyu Ma, peter.senna, martin.donnelly, andrzej.hajda,
narmstrong, robert.foss, Laurent.pinchart, jonas, jernej.skrabec,
airlied, daniel
Cc: dri-devel, linux-kernel
On Sat, 2022-07-16 at 16:13 +0800, Zheyu Ma wrote:
> When removing the module we will get the following warning:
>
> [ 31.911505] i2c-core: driver [stdp2690-ge-b850v3-fw] unregistered
> [ 31.912484] general protection fault, probably for non-canonical
> address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
> [ 31.913338] KASAN: null-ptr-deref in range [0x0000000000000008-
> 0x000000000000000f]
> [ 31.915280] RIP: 0010:drm_bridge_remove+0x97/0x130
> [ 31.921825] Call Trace:
> [ 31.922533] stdp4028_ge_b850v3_fw_remove+0x34/0x60
> [megachips_stdpxxxx_ge_b850v3_fw]
> [ 31.923139] i2c_device_remove+0x181/0x1f0
>
> The two bridges (stdp2690, stdp4028) do not probe at the same time,
> so
> the driver does not call ge_b850v3_resgiter() when probing, causing
> the
> driver to try to remove the object that has not been initialized.
>
> Fix this by checking whether both the bridges are probed.
>
> Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Good catch!
Acked-by: Martyn Welch <martyn.welch@collabora.com>
Would be worth adding:
Fixes: 11632d4aa2b3 ("drm/bridge: megachips: Ensure both bridges are
probed before registration")
> ---
> drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> index cce98bf2a4e7..c68a4cdf4625 100644
> --- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> +++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> @@ -296,7 +296,9 @@ static void ge_b850v3_lvds_remove(void)
> * This check is to avoid both the drivers
> * removing the bridge in their remove() function
> */
> - if (!ge_b850v3_lvds_ptr)
> + if (!ge_b850v3_lvds_ptr ||
> + !ge_b850v3_lvds_ptr->stdp2690_i2c ||
> + !ge_b850v3_lvds_ptr->stdp4028_i2c)
> goto out;
>
> drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] drm/bridge: megachips: Fix a null pointer dereference bug
2022-07-19 8:38 ` Martyn Welch
@ 2022-08-02 12:04 ` Ian Ray
0 siblings, 0 replies; 5+ messages in thread
From: Ian Ray @ 2022-08-02 12:04 UTC (permalink / raw)
To: Martyn Welch
Cc: Zheyu Ma, peter.senna, andrzej.hajda, narmstrong, robert.foss,
Laurent.pinchart, jonas, jernej.skrabec, airlied, daniel,
dri-devel, linux-kernel
On Tue, Jul 19, 2022 at 09:38:16AM +0100, Martyn Welch wrote:
> On Sat, 2022-07-16 at 16:13 +0800, Zheyu Ma wrote:
> > When removing the module we will get the following warning:
> >
> > [ 31.911505] i2c-core: driver [stdp2690-ge-b850v3-fw] unregistered
> > [ 31.912484] general protection fault, probably for non-canonical
> > address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
> > [ 31.913338] KASAN: null-ptr-deref in range [0x0000000000000008-
> > 0x000000000000000f]
> > [ 31.915280] RIP: 0010:drm_bridge_remove+0x97/0x130
> > [ 31.921825] Call Trace:
> > [ 31.922533] stdp4028_ge_b850v3_fw_remove+0x34/0x60
> > [megachips_stdpxxxx_ge_b850v3_fw]
> > [ 31.923139] i2c_device_remove+0x181/0x1f0
> >
> > The two bridges (stdp2690, stdp4028) do not probe at the same time,
> > so
> > the driver does not call ge_b850v3_resgiter() when probing, causing
> > the
> > driver to try to remove the object that has not been initialized.
> >
> > Fix this by checking whether both the bridges are probed.
> >
> > Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
>
> Good catch!
>
> Acked-by: Martyn Welch <martyn.welch@collabora.com>
Tested-by: Ian Ray <ian.ray@ge.com>
>
> Would be worth adding:
>
> Fixes: 11632d4aa2b3 ("drm/bridge: megachips: Ensure both bridges are
> probed before registration")
>
> > ---
> > drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> > b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> > index cce98bf2a4e7..c68a4cdf4625 100644
> > --- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> > +++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> > @@ -296,7 +296,9 @@ static void ge_b850v3_lvds_remove(void)
> > * This check is to avoid both the drivers
> > * removing the bridge in their remove() function
> > */
> > - if (!ge_b850v3_lvds_ptr)
> > + if (!ge_b850v3_lvds_ptr ||
> > + !ge_b850v3_lvds_ptr->stdp2690_i2c ||
> > + !ge_b850v3_lvds_ptr->stdp4028_i2c)
> > goto out;
> >
> > drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] drm/bridge: megachips: Fix a null pointer dereference bug
2022-07-16 8:13 [PATCH] drm/bridge: megachips: Fix a null pointer dereference bug Zheyu Ma
2022-07-19 8:38 ` Martyn Welch
@ 2022-08-29 15:03 ` Robert Foss
2022-08-30 7:36 ` Zheyu Ma
1 sibling, 1 reply; 5+ messages in thread
From: Robert Foss @ 2022-08-29 15:03 UTC (permalink / raw)
To: Zheyu Ma
Cc: peter.senna, martin.donnelly, martyn.welch, andrzej.hajda,
narmstrong, Laurent.pinchart, jonas, jernej.skrabec, airlied,
daniel, dri-devel, linux-kernel
On Sat, 16 Jul 2022 at 10:13, Zheyu Ma <zheyuma97@gmail.com> wrote:
>
> When removing the module we will get the following warning:
>
> [ 31.911505] i2c-core: driver [stdp2690-ge-b850v3-fw] unregistered
> [ 31.912484] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
> [ 31.913338] KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
> [ 31.915280] RIP: 0010:drm_bridge_remove+0x97/0x130
> [ 31.921825] Call Trace:
> [ 31.922533] stdp4028_ge_b850v3_fw_remove+0x34/0x60 [megachips_stdpxxxx_ge_b850v3_fw]
> [ 31.923139] i2c_device_remove+0x181/0x1f0
>
> The two bridges (stdp2690, stdp4028) do not probe at the same time, so
> the driver does not call ge_b850v3_resgiter() when probing, causing the
> driver to try to remove the object that has not been initialized.
>
> Fix this by checking whether both the bridges are probed.
>
> Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
> ---
> drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> index cce98bf2a4e7..c68a4cdf4625 100644
> --- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> +++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> @@ -296,7 +296,9 @@ static void ge_b850v3_lvds_remove(void)
> * This check is to avoid both the drivers
> * removing the bridge in their remove() function
> */
> - if (!ge_b850v3_lvds_ptr)
> + if (!ge_b850v3_lvds_ptr ||
> + !ge_b850v3_lvds_ptr->stdp2690_i2c ||
> + !ge_b850v3_lvds_ptr->stdp4028_i2c)
This chunk fails checkpatch --strict.
Alignment should match open parenthesis
#39: FILE: drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c:300:
> goto out;
>
> drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] drm/bridge: megachips: Fix a null pointer dereference bug
2022-08-29 15:03 ` Robert Foss
@ 2022-08-30 7:36 ` Zheyu Ma
0 siblings, 0 replies; 5+ messages in thread
From: Zheyu Ma @ 2022-08-30 7:36 UTC (permalink / raw)
To: Robert Foss
Cc: peter.senna, martin.donnelly, martyn.welch, andrzej.hajda,
narmstrong, Laurent.pinchart, jonas, jernej.skrabec, airlied,
Daniel Vetter, DRI Development, Linux Kernel Mailing List
Hi Robert,
On Mon, Aug 29, 2022 at 11:03 PM Robert Foss <robert.foss@linaro.org> wrote:
>
> On Sat, 16 Jul 2022 at 10:13, Zheyu Ma <zheyuma97@gmail.com> wrote:
> >
> > When removing the module we will get the following warning:
> >
> > [ 31.911505] i2c-core: driver [stdp2690-ge-b850v3-fw] unregistered
> > [ 31.912484] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
> > [ 31.913338] KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
> > [ 31.915280] RIP: 0010:drm_bridge_remove+0x97/0x130
> > [ 31.921825] Call Trace:
> > [ 31.922533] stdp4028_ge_b850v3_fw_remove+0x34/0x60 [megachips_stdpxxxx_ge_b850v3_fw]
> > [ 31.923139] i2c_device_remove+0x181/0x1f0
> >
> > The two bridges (stdp2690, stdp4028) do not probe at the same time, so
> > the driver does not call ge_b850v3_resgiter() when probing, causing the
> > driver to try to remove the object that has not been initialized.
> >
> > Fix this by checking whether both the bridges are probed.
> >
> > Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
> > ---
> > drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> > index cce98bf2a4e7..c68a4cdf4625 100644
> > --- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> > +++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> > @@ -296,7 +296,9 @@ static void ge_b850v3_lvds_remove(void)
> > * This check is to avoid both the drivers
> > * removing the bridge in their remove() function
> > */
> > - if (!ge_b850v3_lvds_ptr)
> > + if (!ge_b850v3_lvds_ptr ||
> > + !ge_b850v3_lvds_ptr->stdp2690_i2c ||
> > + !ge_b850v3_lvds_ptr->stdp4028_i2c)
>
> This chunk fails checkpatch --strict.
>
> Alignment should match open parenthesis
> #39: FILE: drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c:300:
Thanks for your suggestion, I've sent the version 2 patch.
Regards,
Zheyu Ma
^ permalink raw reply [flat|nested] 5+ messages in thread
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2022-07-16 8:13 [PATCH] drm/bridge: megachips: Fix a null pointer dereference bug Zheyu Ma
2022-07-19 8:38 ` Martyn Welch
2022-08-02 12:04 ` Ian Ray
2022-08-29 15:03 ` Robert Foss
2022-08-30 7:36 ` Zheyu Ma
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