[PATCH v7] misc: fastrpc: check qcom_scm_assign_mem() return in rpmsg_probe

[Xingjing Deng]

In the SDSP probe path, qcom_scm_assign_mem() is used to assign the
reserved memory to the configured VMIDs, but its return value was not checked.

Fail the probe if the SCM call fails to avoid continuing with an
unexpected/incorrect memory permission configuration.

This issue was found by an in-house analysis workflow that extracts AST-based
information and runs static checks, with LLM assistance for triage, and was
confirmed by manual code review.
No hardware testing was performed.

Fixes: c3c0363bc72d4 ("misc: fastrpc: support complete DMA pool access to the DSP")
Cc: stable@xxxxxxxxxxxxxxx # 6.11-rc1
Signed-off-by: Xingjing Deng <xjdeng@xxxxxxxxxxx>
---
v7:
- Add the detail description of how the tool detect.
- Link to v6: https://lore.kernel.org/linux-arm-msm/20260128033454.2614886-1-xjdeng@xxxxxxxxxxx/

v6:
- Add description of the detection tool.
- Link to v5: https://lore.kernel.org/linux-arm-msm/20260117140351.875511-1-xjdeng@xxxxxxxxxxx/T/#u

v5:
- Squash the functional change and indentation fix into a single patch.
- Link to v4: https://lore.kernel.org/linux-arm-msm/2026011637-statute-showy-2c3f@gregkh/T/#t

v4:
- Format the indentation
- Link to v3: https://lore.kernel.org/linux-arm-msm/20260113084352.72itrloj5w7qb5o3@xxxxxxxxxxxxxxxxxxxxxxxxx/T/#t

v3:
- Add missing linux-kernel@xxxxxxxxxxxxxxx to cc list.
- Standarlize changelog placement/format.
- Link to v2: https://lore.kernel.org/linux-arm-msm/20260113063618.e2ke47gy3hnfi67e@xxxxxxxxxxxxxxxxxxxxxxxxx/T/#t

v2:
- Add Fixes: and Cc: stable tags.
- Link to v1: https://lore.kernel.org/linux-arm-msm/20260113022550.4029635-1-xjdeng@xxxxxxxxxxx/T/#u
---
 drivers/misc/fastrpc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index ee652ef01534..8bac2216cb20 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -2337,8 +2337,11 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 		if (!err) {
 			src_perms = BIT(QCOM_SCM_VMID_HLOS);
 
-			qcom_scm_assign_mem(res.start, resource_size(&res), &src_perms,
+			err = qcom_scm_assign_mem(res.start, resource_size(&res), &src_perms,
 				    data->vmperms, data->vmcount);
+			if (err) {
+				goto err_free_data;
+			}
 		}
 
 	}
-- 
2.25.1