[PATCH v4] media: verisilicon: Fix kernel panic due to __initconst misuse

[ming.qian@oss.nxp.com]

From: Ming Qian <ming.qian@oss.nxp.com>

Fix a kernel panic when probing the driver as a module:

  Unable to handle kernel paging request at virtual address
  ffffd9c18eb05000
  of_find_matching_node_and_match+0x5c/0x1a0
  hantro_probe+0x2f4/0x7d0 [hantro_vpu]

The imx8mq_vpu_shared_resources array is referenced by variant
structures through their shared_devices field. When built as a
module, __initconst causes this data to be freed after module
init, but it's later accessed during probe, causing a page fault.

The imx8mq_vpu_shared_resources is referenced from non-init code,
so keeping __initconst or __initconst_or_module here is wrong.

Drop the __initconst annotation and let it live in the normal .rodata
section.

A bug of __initconst called from regular non-init probe code
leading to bugs during probe deferrals or during unbind-bind cycles.

Reported-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Closes: https://lore.kernel.org/all/68ef934f-baa0-4bf6-93d8-834bbc441e66@kernel.org/
Reported-by: Franz Schnyder <franz.schnyder@toradex.com>
Closes: https://lore.kernel.org/all/n3qmcb62tepxltoskpf7ws6yiirc2so62ia23b42rj3wlmpl67@rvkbuirx7kkp/
Fixes: e0203ddf9af7 ("media: verisilicon: Avoid G2 bus error while decoding H.264 and HEVC")
Suggested-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Suggested-by: Marco Felsch <m.felsch@pengutronix.de>
Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
---
v4
- Increase the diff context length to pass the checkpatch.pl.
- Discard irrelevant changes to sentinel

v3
- Add missing Reported-by and Suggested-by tag
- Add commas to pass checkpatch

v2
- Remove __initconst
- Add missing Reported-by tag
- Add missing Suggested-by tag
- Remove comments of sentinel to pass checkpatch.pl

 drivers/media/platform/verisilicon/imx8m_vpu_hw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/verisilicon/imx8m_vpu_hw.c b/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
index 6f8e43b7f157..fa4224de4b99 100644
--- a/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
+++ b/drivers/media/platform/verisilicon/imx8m_vpu_hw.c
@@ -342,9 +342,9 @@ const struct hantro_variant imx8mq_vpu_variant = {
 	.reg_names = imx8mq_reg_names,
 	.num_regs = ARRAY_SIZE(imx8mq_reg_names)
 };
 
-static const struct of_device_id imx8mq_vpu_shared_resources[] __initconst = {
+static const struct of_device_id imx8mq_vpu_shared_resources[] = {
 	{ .compatible = "nxp,imx8mq-vpu-g1", },
 	{ .compatible = "nxp,imx8mq-vpu-g2", },
 	{ /* sentinel */ }
 };

base-commit: f505e978d1a0442adbbde48aed38c084ddea6d6e
prerequisite-patch-id: 0000000000000000000000000000000000000000
-- 
2.52.0