From c38cce70adef874c2a7b5132c14d6c221401deff Mon Sep 17 00:00:00 2001 From: Linmao Li Date: Mon, 6 Jul 2026 09:20:56 +0800 Subject: [PATCH] platform/mellanox: mlxbf-pmc: Check ACPI_COMPANION() against NULL MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Every platform driver can be forced to match a device that doesn't match its list of device IDs because of device_match_driver_override(), so platform drivers that rely on the existence of a device's ACPI companion object need to verify its presence. mlxbf_pmc_probe() passes the result of ACPI_COMPANION() to acpi_device_hid(), which dereferences it, so force-binding the driver to a device without an ACPI companion leads to a NULL pointer dereference. Accordingly, add a requisite ACPI_COMPANION() check against NULL to the mlxbf-pmc driver and return -ENODEV when the companion is missing. Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField PMC driver") Signed-off-by: Linmao Li Link: https://patch.msgid.link/20260706012056.524096-1-lilinmao@kylinos.cn Reviewed-by: Ilpo Järvinen Signed-off-by: Ilpo Järvinen --- drivers/platform/mellanox/mlxbf-pmc.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/platform/mellanox/mlxbf-pmc.c b/drivers/platform/mellanox/mlxbf-pmc.c index 5ec1ad471696..2ad9e2b0493c 100644 --- a/drivers/platform/mellanox/mlxbf-pmc.c +++ b/drivers/platform/mellanox/mlxbf-pmc.c @@ -2262,13 +2262,19 @@ static int mlxbf_pmc_map_counters(struct device *dev) static int mlxbf_pmc_probe(struct platform_device *pdev) { - struct acpi_device *acpi_dev = ACPI_COMPANION(&pdev->dev); - const char *hid = acpi_device_hid(acpi_dev); struct device *dev = &pdev->dev; + struct acpi_device *acpi_dev; struct arm_smccc_res res; + const char *hid; guid_t guid; int ret; + acpi_dev = ACPI_COMPANION(&pdev->dev); + if (!acpi_dev) + return -ENODEV; + + hid = acpi_device_hid(acpi_dev); + /* Ensure we have the UUID we expect for this service. */ arm_smccc_smc(MLXBF_PMC_SIP_SVC_UID, 0, 0, 0, 0, 0, 0, 0, &res); guid_parse(mlxbf_pmc_svc_uuid_str, &guid);