drm/mediatek: Add missing IS_ERR check for ovl_adaptor platform devicegrafted

platform_device_register_data() can fail and return an ERR_PTR, but the
return value is used without checking, leading to an invalid pointer
being stored in ddp_comp[].dev and passed to component_match_add() and
mtk_ddp_comp_init(), which could result in a kernel crash.

Add an IS_ERR() check to jump to the error handling path on failure.

Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
Cc: stable@vger.kernel.org
Signed-off-by: Haojie Li <lihaojie@kylinos.cn>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260825100845.438893-1-lihaojie@kylinos.cn/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/Documentation/admin-guide/sysctl/debug.rst b/Documentation/admin-guide/sysctl/debug.rst
new file mode 100644
index 000000000..506bd5e48
--- /dev/null
+++ b/Documentation/admin-guide/sysctl/debug.rst
@@ -0,0 +1,52 @@
+================
+/proc/sys/debug/
+================
+
+These files show up in ``/proc/sys/debug/``, depending on the
+kernel configuration:
+
+.. contents:: :local:
+
+exception-trace
+===============
+
+This flag controls whether the kernel prints information about unhandled
+signals (like segmentation faults) to the kernel log (``dmesg``).
+
+- ``0``: Unhandled signals are not traced.
+- ``1``: Information about unhandled signals is printed.
+
+The default value is ``1`` on most architectures (like x86, MIPS, RISC-V),
+but it is ``0`` on **arm64**.
+
+The actual information printed and the context provided varies
+significantly depending on the CPU architecture. For example:
+
+- On **x86**, it typically prints the instruction pointer (IP), error
+  code, and address that caused a page fault.
+- On **PowerPC**, it may print the next instruction pointer (NIP),
+  link register (LR), and other relevant registers.
+
+When enabled, this feature is often rate-limited to prevent the kernel
+log from being flooded during a crash loop.
+
+kprobes-optimization
+====================
+
+This flag enables or disables the optimization of Kprobes on certain
+architectures (like x86).
+
+- ``0``: Kprobes optimization is turned off.
+- ``1``: Kprobes optimization is turned on (default).
+
+For more details on Kprobes and its optimization, please refer to
+Documentation/trace/kprobes.rst.
+
+Copyright (c) 2026, Shubham Chakraborty <chakrabortyshubham66@gmail.com>
+
+For general info and legal blurb, please look in
+Documentation/admin-guide/sysctl/index.rst.
+
+.. See scripts/check-sysctl-docs to keep this up to date:
+.. scripts/check-sysctl-docs -vtable="debug" \
+..         $(git grep -l register_sysctl_)