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[PATCH v2 0/3] drm/display: bridge_connector: get/put the stored bridges: fix NULL pointer regression

Luca Ceresoli posted 3 patches 3 months, 3 weeks ago 
drivers/gpu/drm/display/drm_bridge_connector.c | 92 +++++++++++---------------
1 file changed, 39 insertions(+), 53 deletions(-)
[PATCH v2 0/3] drm/display: bridge_connector: get/put the stored bridges: fix NULL pointer regression
Posted by Luca Ceresoli 3 months, 3 weeks ago 
A patch of mine recently merged in drm-misc-next [1] has a NULL pointer
deref regression (reported here [2] and here [3]). Being in lack of a quick
fix, I sent a revert proposal [4].

The revert proposal has no answers currenty, and in the meanwhile I have a
patch that implements the original idea but without the same bug. So here's
a v2 series with:

 - the same revert patch
 - the original patch but rewritten without the same bug (and even simpler)

Also the re-written patch is now split in two for clarity because it was
doing two somewhat different things.

[1] https://lore.kernel.org/all/20250926-drm-bridge-alloc-getput-bridge-connector-v2-1-138b4bb70576@bootlin.com/
[2] https://lore.kernel.org/lkml/336fbfdd-c424-490e-b5d1-8ee84043dc80@samsung.com/
[3] https://lore.kernel.org/lkml/CA+G9fYuKHp3QgPKjgFY3TfkDdh5Vf=Ae5pCW+eU41Bu=D7th2g@mail.gmail.com/
[4] https://lore.kernel.org/lkml/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com/

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
Changes in v2:
- No changes to the revert patch
- Added the (corrected) patch introducing the same feature as the original
  buggy patch, and also split it in two fir clarity
- Link to v1: https://lore.kernel.org/r/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com

---
Luca Ceresoli (3):
      Revert "drm/display: bridge_connector: get/put the stored bridges"
      drm/display: bridge_connector: get/put the stored bridges
      drm/display: bridge_connector: get/put the panel_bridge

 drivers/gpu/drm/display/drm_bridge_connector.c | 92 +++++++++++---------------
 1 file changed, 39 insertions(+), 53 deletions(-)
---
base-commit: 84a0a3f014cda68ff10b8517d09e9f0c1cd942a2
change-id: 20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-9a429ddb48e2

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>
Re: [PATCH v2 0/3] drm/display: bridge_connector: get/put the stored bridges: fix NULL pointer regression
Posted by Luca Ceresoli 3 months, 1 week ago 
On Fri, 17 Oct 2025 18:15:03 +0200, Luca Ceresoli wrote:
> A patch of mine recently merged in drm-misc-next [1] has a NULL pointer
> deref regression (reported here [2] and here [3]). Being in lack of a quick
> fix, I sent a revert proposal [4].
> 
> The revert proposal has no answers currenty, and in the meanwhile I have a
> patch that implements the original idea but without the same bug. So here's
> a v2 series with:
> 
> [...]

Applied, thanks!

[1/3] Revert "drm/display: bridge_connector: get/put the stored bridges"
      commit: b4027536933f813e51cc53be0b7542012f09aa38
[2/3] drm/display: bridge_connector: get/put the stored bridges
      commit: 13adb8c97846603efc7bfc7663dfdc0ba2f34b8f
[3/3] drm/display: bridge_connector: get/put the panel_bridge
      commit: a3f433c57c46776f95fdf4cfaad1ab27dbca7311

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>
Re: [PATCH v2 0/3] drm/display: bridge_connector: get/put the stored bridges: fix NULL pointer regression
Posted by Dmitry Baryshkov 3 months, 1 week ago 
On Fri, Oct 17, 2025 at 06:15:03PM +0200, Luca Ceresoli wrote:
> A patch of mine recently merged in drm-misc-next [1] has a NULL pointer
> deref regression (reported here [2] and here [3]). Being in lack of a quick
> fix, I sent a revert proposal [4].
> 
> The revert proposal has no answers currenty, and in the meanwhile I have a
> patch that implements the original idea but without the same bug. So here's
> a v2 series with:
> 
>  - the same revert patch
>  - the original patch but rewritten without the same bug (and even simpler)
> 
> Also the re-written patch is now split in two for clarity because it was
> doing two somewhat different things.
> 
> [1] https://lore.kernel.org/all/20250926-drm-bridge-alloc-getput-bridge-connector-v2-1-138b4bb70576@bootlin.com/
> [2] https://lore.kernel.org/lkml/336fbfdd-c424-490e-b5d1-8ee84043dc80@samsung.com/
> [3] https://lore.kernel.org/lkml/CA+G9fYuKHp3QgPKjgFY3TfkDdh5Vf=Ae5pCW+eU41Bu=D7th2g@mail.gmail.com/
> [4] https://lore.kernel.org/lkml/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com/
> 
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> ---
> Changes in v2:
> - No changes to the revert patch
> - Added the (corrected) patch introducing the same feature as the original
>   buggy patch, and also split it in two fir clarity
> - Link to v1: https://lore.kernel.org/r/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Tested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com> # db410c



-- 
With best wishes
Dmitry
Re: [PATCH v2 0/3] drm/display: bridge_connector: get/put the stored bridges: fix NULL pointer regression
Posted by Geert Uytterhoeven 3 months, 1 week ago 
Hi Luca,

On Fri, 17 Oct 2025 at 18:58, Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
> A patch of mine recently merged in drm-misc-next [1] has a NULL pointer
> deref regression (reported here [2] and here [3]). Being in lack of a quick
> fix, I sent a revert proposal [4].
>
> The revert proposal has no answers currenty, and in the meanwhile I have a
> patch that implements the original idea but without the same bug. So here's
> a v2 series with:
>
>  - the same revert patch
>  - the original patch but rewritten without the same bug (and even simpler)
>
> Also the re-written patch is now split in two for clarity because it was
> doing two somewhat different things.
>
> [1] https://lore.kernel.org/all/20250926-drm-bridge-alloc-getput-bridge-connector-v2-1-138b4bb70576@bootlin.com/
> [2] https://lore.kernel.org/lkml/336fbfdd-c424-490e-b5d1-8ee84043dc80@samsung.com/
> [3] https://lore.kernel.org/lkml/CA+G9fYuKHp3QgPKjgFY3TfkDdh5Vf=Ae5pCW+eU41Bu=D7th2g@mail.gmail.com/
> [4] https://lore.kernel.org/lkml/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com/
>
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> ---
> Changes in v2:
> - No changes to the revert patch
> - Added the (corrected) patch introducing the same feature as the original
>   buggy patch, and also split it in two fir clarity
> - Link to v1: https://lore.kernel.org/r/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com

Thanks, this fixes the crash I experienced on Koelsch (R-Car M2-W)
(https://lore.kernel.org/CAMuHMdW=zEi4XjG2Qrvj=jCa9LPBRU7HBTwEQVbe0zoz5mV_XA@mail.gmail.com)

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Re: [PATCH v2 0/3] drm/display: bridge_connector: get/put the stored bridges: fix NULL pointer regression
Posted by Tommaso Merciai 3 months, 2 weeks ago 
Hi Luca,

Thank you for your patch!

On Fri, Oct 17, 2025 at 06:15:03PM +0200, Luca Ceresoli wrote:
> A patch of mine recently merged in drm-misc-next [1] has a NULL pointer
> deref regression (reported here [2] and here [3]). Being in lack of a quick
> fix, I sent a revert proposal [4].
> 
> The revert proposal has no answers currenty, and in the meanwhile I have a
> patch that implements the original idea but without the same bug. So here's
> a v2 series with:
> 
>  - the same revert patch
>  - the original patch but rewritten without the same bug (and even simpler)
> 
> Also the re-written patch is now split in two for clarity because it was
> doing two somewhat different things.
> 
> [1] https://lore.kernel.org/all/20250926-drm-bridge-alloc-getput-bridge-connector-v2-1-138b4bb70576@bootlin.com/
> [2] https://lore.kernel.org/lkml/336fbfdd-c424-490e-b5d1-8ee84043dc80@samsung.com/
> [3] https://lore.kernel.org/lkml/CA+G9fYuKHp3QgPKjgFY3TfkDdh5Vf=Ae5pCW+eU41Bu=D7th2g@mail.gmail.com/
> [4] https://lore.kernel.org/lkml/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com/
> 

Tested on RZ/G3E board using DSI output.
Tested-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>

Thanks & Regards,
Tommaso

> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> ---
> Changes in v2:
> - No changes to the revert patch
> - Added the (corrected) patch introducing the same feature as the original
>   buggy patch, and also split it in two fir clarity
> - Link to v1: https://lore.kernel.org/r/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com
> 
> ---
> Luca Ceresoli (3):
>       Revert "drm/display: bridge_connector: get/put the stored bridges"
>       drm/display: bridge_connector: get/put the stored bridges
>       drm/display: bridge_connector: get/put the panel_bridge
> 
>  drivers/gpu/drm/display/drm_bridge_connector.c | 92 +++++++++++---------------
>  1 file changed, 39 insertions(+), 53 deletions(-)
> ---
> base-commit: 84a0a3f014cda68ff10b8517d09e9f0c1cd942a2
> change-id: 20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-9a429ddb48e2
> 
> Best regards,
> -- 
> Luca Ceresoli <luca.ceresoli@bootlin.com>
>
Re: [PATCH v2 0/3] drm/display: bridge_connector: get/put the stored bridges: fix NULL pointer regression
Posted by Marek Szyprowski 3 months, 3 weeks ago 
On 17.10.2025 18:15, Luca Ceresoli wrote:
> A patch of mine recently merged in drm-misc-next [1] has a NULL pointer
> deref regression (reported here [2] and here [3]). Being in lack of a quick
> fix, I sent a revert proposal [4].
>
> The revert proposal has no answers currenty, and in the meanwhile I have a
> patch that implements the original idea but without the same bug. So here's
> a v2 series with:
>
>   - the same revert patch
>   - the original patch but rewritten without the same bug (and even simpler)
>
> Also the re-written patch is now split in two for clarity because it was
> doing two somewhat different things.
>
> [1] https://lore.kernel.org/all/20250926-drm-bridge-alloc-getput-bridge-connector-v2-1-138b4bb70576@bootlin.com/
> [2] https://lore.kernel.org/lkml/336fbfdd-c424-490e-b5d1-8ee84043dc80@samsung.com/
> [3] https://lore.kernel.org/lkml/CA+G9fYuKHp3QgPKjgFY3TfkDdh5Vf=Ae5pCW+eU41Bu=D7th2g@mail.gmail.com/
> [4] https://lore.kernel.org/lkml/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com/
>
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Works fine on all boards in my test lab.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

> ---
> Changes in v2:
> - No changes to the revert patch
> - Added the (corrected) patch introducing the same feature as the original
>    buggy patch, and also split it in two fir clarity
> - Link to v1: https://lore.kernel.org/r/20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-v1-1-81d6984c5361@bootlin.com
>
> ---
> Luca Ceresoli (3):
>        Revert "drm/display: bridge_connector: get/put the stored bridges"
>        drm/display: bridge_connector: get/put the stored bridges
>        drm/display: bridge_connector: get/put the panel_bridge
>
>   drivers/gpu/drm/display/drm_bridge_connector.c | 92 +++++++++++---------------
>   1 file changed, 39 insertions(+), 53 deletions(-)
> ---
> base-commit: 84a0a3f014cda68ff10b8517d09e9f0c1cd942a2
> change-id: 20251016-drm-bridge-alloc-getput-bridge-connector-fix-hdmi_cec-9a429ddb48e2
>
> Best regards,

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Patchew 2.1-devel-b67e4c2

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