[PATCH 6.6.y] drm/sysfb: Do not dereference NULL pointer in plane reset

[PATCH 6.6.y] drm/sysfb: Do not dereference NULL pointer in plane reset

[Sasha Levin]

From: Thomas Zimmermann <tzimmermann@suse.de>

[ Upstream commit 14e02ed3876f4ab0ed6d3f41972175f8b8df3d70 ]

The plane state in __drm_gem_reset_shadow_plane() can be NULL. Do not
deref that pointer, but forward NULL to the other plane-reset helpers.
Clears plane->state to NULL.

v2:
- fix typo in commit description (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: b71565022031 ("drm/gem: Export implementation of shadow-plane helpers")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/dri-devel/aPIDAsHIUHp_qSW4@stanley.mountain/
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Melissa Wen <melissa.srw@gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.15+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patch.msgid.link/20251017091407.58488-1-tzimmermann@suse.de
[ removed drm_format_conv_state_init() call ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/drm_gem_atomic_helper.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
index 5d4b9cd077f7a..e0ea3c661cb77 100644
--- a/drivers/gpu/drm/drm_gem_atomic_helper.c
+++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
@@ -301,7 +301,11 @@ EXPORT_SYMBOL(drm_gem_destroy_shadow_plane_state);
 void __drm_gem_reset_shadow_plane(struct drm_plane *plane,
 				  struct drm_shadow_plane_state *shadow_plane_state)
 {
-	__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
+	if (shadow_plane_state) {
+		__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
+	} else {
+		__drm_atomic_helper_plane_reset(plane, NULL);
+	}
 }
 EXPORT_SYMBOL(__drm_gem_reset_shadow_plane);
 
-- 
2.51.0

Re: [PATCH 6.6.y] drm/sysfb: Do not dereference NULL pointer in plane reset

[Thomas Zimmermann]

Am 03.11.25 um 13:47 schrieb Sasha Levin:
> From: Thomas Zimmermann <tzimmermann@suse.de>
>
> [ Upstream commit 14e02ed3876f4ab0ed6d3f41972175f8b8df3d70 ]
>
> The plane state in __drm_gem_reset_shadow_plane() can be NULL. Do not
> deref that pointer, but forward NULL to the other plane-reset helpers.
> Clears plane->state to NULL.
>
> v2:
> - fix typo in commit description (Javier)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Fixes: b71565022031 ("drm/gem: Export implementation of shadow-plane helpers")
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/dri-devel/aPIDAsHIUHp_qSW4@stanley.mountain/
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Melissa Wen <melissa.srw@gmail.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Simona Vetter <simona@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v5.15+
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
> Link: https://patch.msgid.link/20251017091407.58488-1-tzimmermann@suse.de
> [ removed drm_format_conv_state_init() call ]
> Signed-off-by: Sasha Levin <sashal@kernel.org>

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

> ---
>   drivers/gpu/drm/drm_gem_atomic_helper.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
> index 5d4b9cd077f7a..e0ea3c661cb77 100644
> --- a/drivers/gpu/drm/drm_gem_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
> @@ -301,7 +301,11 @@ EXPORT_SYMBOL(drm_gem_destroy_shadow_plane_state);
>   void __drm_gem_reset_shadow_plane(struct drm_plane *plane,
>   				  struct drm_shadow_plane_state *shadow_plane_state)
>   {
> -	__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
> +	if (shadow_plane_state) {
> +		__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
> +	} else {
> +		__drm_atomic_helper_plane_reset(plane, NULL);
> +	}
>   }
>   EXPORT_SYMBOL(__drm_gem_reset_shadow_plane);
>   

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)

Patch "drm/sysfb: Do not dereference NULL pointer in plane reset" has been added to the 6.6-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    drm/sysfb: Do not dereference NULL pointer in plane reset

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-sysfb-do-not-dereference-null-pointer-in-plane-reset.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From stable+bounces-192201-greg=kroah.com@vger.kernel.org Mon Nov  3 21:50:23 2025
From: Sasha Levin <sashal@kernel.org>
Date: Mon,  3 Nov 2025 07:47:27 -0500
Subject: drm/sysfb: Do not dereference NULL pointer in plane reset
To: stable@vger.kernel.org
Cc: Thomas Zimmermann <tzimmermann@suse.de>, Dan Carpenter <dan.carpenter@linaro.org>, Melissa Wen <melissa.srw@gmail.com>, Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>, dri-devel@lists.freedesktop.org, Javier Martinez Canillas <javierm@redhat.com>, Sasha Levin <sashal@kernel.org>
Message-ID: <20251103124727.4003872-1-sashal@kernel.org>

From: Thomas Zimmermann <tzimmermann@suse.de>

[ Upstream commit 14e02ed3876f4ab0ed6d3f41972175f8b8df3d70 ]

The plane state in __drm_gem_reset_shadow_plane() can be NULL. Do not
deref that pointer, but forward NULL to the other plane-reset helpers.
Clears plane->state to NULL.

v2:
- fix typo in commit description (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: b71565022031 ("drm/gem: Export implementation of shadow-plane helpers")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/dri-devel/aPIDAsHIUHp_qSW4@stanley.mountain/
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Melissa Wen <melissa.srw@gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.15+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patch.msgid.link/20251017091407.58488-1-tzimmermann@suse.de
[ removed drm_format_conv_state_init() call ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/drm_gem_atomic_helper.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_gem_atomic_helper.c
+++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
@@ -301,7 +301,11 @@ EXPORT_SYMBOL(drm_gem_destroy_shadow_pla
 void __drm_gem_reset_shadow_plane(struct drm_plane *plane,
 				  struct drm_shadow_plane_state *shadow_plane_state)
 {
-	__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
+	if (shadow_plane_state) {
+		__drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base);
+	} else {
+		__drm_atomic_helper_plane_reset(plane, NULL);
+	}
 }
 EXPORT_SYMBOL(__drm_gem_reset_shadow_plane);
 


Patches currently in stable-queue which might be from sashal@kernel.org are

queue-6.6/bluetooth-hci-fix-tracking-of-advertisement-set-inst.patch
queue-6.6/cpuidle-governors-menu-select-polling-state-in-some-more-cases.patch
queue-6.6/drm-amd-pm-powerplay-smumgr-fix-pciebootlinklevel-va.patch
queue-6.6/wifi-ath10k-fix-memory-leak-on-unsupported-wmi-comma.patch
queue-6.6/s390-pci-restore-irq-unconditionally-for-the-zpci-device.patch
queue-6.6/asoc-fsl_sai-fix-bit-order-for-dsd-format.patch
queue-6.6/bluetooth-hci_core-fix-tracking-of-periodic-advertis.patch
queue-6.6/net-hns3-return-error-code-when-function-fails.patch
queue-6.6/mptcp-fix-msg_peek-stream-corruption.patch
queue-6.6/asoc-intel-avs-unprepare-a-stream-when-xrun-occurs.patch
queue-6.6/drm-etnaviv-fix-flush-sequence-logic.patch
queue-6.6/bluetooth-iso-fix-another-instance-of-dst_type-handl.patch
queue-6.6/s390-pci-avoid-deadlock-between-pci-error-recovery-and-mlx5-crdump.patch
queue-6.6/crypto-aspeed-acry-convert-to-platform-remove-callba.patch
queue-6.6/sfc-fix-potential-memory-leak-in-efx_mae_process_mpo.patch
queue-6.6/drm-msm-a6xx-fix-gmu-firmware-parser.patch
queue-6.6/cpuidle-governors-menu-rearrange-main-loop-in-menu_select.patch
queue-6.6/wifi-ath12k-free-skb-during-idr-cleanup-callback.patch
queue-6.6/bluetooth-hci_sync-fix-race-in-hci_cmd_sync_dequeue_.patch
queue-6.6/scsi-ufs-core-initialize-value-of-an-attribute-retur.patch
queue-6.6/bluetooth-btmtksdio-add-pmctrl-handling-for-bt-close.patch
queue-6.6/drm-sched-fix-race-in-drm_sched_entity_select_rq.patch
queue-6.6/bpf-sync-pending-irq-work-before-freeing-ring-buffer.patch
queue-6.6/alsa-usb-audio-fix-control-pipe-direction.patch
queue-6.6/drm-sysfb-do-not-dereference-null-pointer-in-plane-reset.patch
queue-6.6/drm-amd-pm-fix-smu-table-id-bound-check-issue-in-smu.patch
queue-6.6/drm-amd-pm-powerplay-smumgr-fix-pciebootlinklevel-va.patch-21603
queue-6.6/usbnet-prevents-free-active-kevent.patch
queue-6.6/bpf-do-not-audit-capability-check-in-do_jit.patch
queue-6.6/crypto-aspeed-fix-double-free-caused-by-devm.patch
queue-6.6/net-phy-dp83867-disable-eee-support-as-not-implemented.patch
queue-6.6/wifi-ath11k-add-missing-platform-ids-for-quirk-table.patch
queue-6.6/libbpf-fix-powerpc-s-stack-register-definition-in-bp.patch