[PATCH 6.9 173/374] drm/msm/dpu: Add callback function pointer check before its call

Greg Kroah-Hartman
2024-06-06T14:09:46Z

From: Aleksandr Mishin <amishin@t-argos.ru>

[ Upstream commit 530f272053a5e72243a9cb07bb1296af6c346002 ]

In dpu_core_irq_callback_handler() callback function pointer is compared to NULL,
but then callback function is unconditionally called by this pointer.
Fix this bug by adding conditional return.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: c929ac60b3ed ("drm/msm/dpu: allow just single IRQ callback")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/588237/
Link: https://lore.kernel.org/r/20240408085523.12231-1-amishin@t-argos.ru
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
index 6a0a74832fb64..b85881aab0478 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
@@ -223,9 +223,11 @@ static void dpu_core_irq_callback_handler(struct dpu_kms *dpu_kms, unsigned int

VERB("IRQ=[%d, %d]\n", DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));

- if (!irq_entry->cb)
+ if (!irq_entry->cb) {
DRM_ERROR("no registered cb, IRQ=[%d, %d]\n",
DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
+ return;
+ }

atomic_inc(&irq_entry->count);

--
2.43.0