[PATCH 12/21] soundwire: amd: Check for NULL manager drvdata in sdw_amd_startup()

[Lee Jones <lee@kernel.org>]

If amd_sdw_manager_probe() fails or defers when registering a SoundWire
manager platform device, dev_get_drvdata(&ctx->pdev[i]->dev) returns
NULL.  sdw_amd_startup() passes this pointer directly to
amd_sdw_manager_start(), which dereferences it unconditionally.

Return -ENODEV in sdw_amd_startup() if dev_get_drvdata() returns NULL,
matching sdw_amd_get_slave_info(), and clean up the allocated context
and platform devices via sdw_amd_exit() if sdw_amd_startup() fails in
sdw_amd_probe().

Fixes: ed5e8741b8db ("soundwire: amd: refactor amd soundwire manager device node creation")
Closes: https://sashiko.dev/#/bug/linux-6834a8a0-632f-4c73-9174-0fe7e06b5303
Cc: stable@vger.kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
---
 drivers/soundwire/amd_init.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/amd_init.c b/drivers/soundwire/amd_init.c
index 8e419ddfa516..adf410fafb7e 100644
--- a/drivers/soundwire/amd_init.c
+++ b/drivers/soundwire/amd_init.c
@@ -156,6 +156,8 @@ static int sdw_amd_startup(struct sdw_amd_ctx *ctx)
 		if (!(ctx->link_mask & BIT(i)))
 			continue;
 		amd_manager = dev_get_drvdata(&ctx->pdev[i]->dev);
+		if (!amd_manager)
+			return -ENODEV;
 		ret = amd_sdw_manager_start(amd_manager);
 		if (ret)
 			return ret;
@@ -166,11 +168,20 @@ static int sdw_amd_startup(struct sdw_amd_ctx *ctx)
 
 int sdw_amd_probe(struct sdw_amd_res *res, struct sdw_amd_ctx **sdw_ctx)
 {
+	int ret;
+
 	*sdw_ctx = sdw_amd_probe_controller(res);
 	if (!*sdw_ctx)
 		return -ENODEV;
 
-	return sdw_amd_startup(*sdw_ctx);
+	ret = sdw_amd_startup(*sdw_ctx);
+	if (ret) {
+		sdw_amd_exit(*sdw_ctx);
+		*sdw_ctx = NULL;
+		return ret;
+	}
+
+	return 0;
 }
 EXPORT_SYMBOL_NS(sdw_amd_probe, "SOUNDWIRE_AMD_INIT");
 
-- 
2.56.0.317.g454f8302e1-goog