[PATCH] ACPI: SBS: Fix NULL pointer dereference on allocation failure

[Guangshuo Li]

acpi_sbs_probe() jumps to the common error path when kzalloc_obj()
fails, but platform_set_drvdata() is only called after the allocation
succeeds.

The error path calls acpi_sbs_remove(), which retrieves the unset
driver data and dereferences the resulting NULL pointer when locking
sbs->lock, causing a NULL pointer dereference.

Return -ENOMEM directly when the allocation fails, since no resources
have been initialized at that point and there is nothing to clean up.

This issue was found by manual code inspection.

Fixes: 9460eaae2ee42 ("ACPI: SBS: Convert the driver to a platform one")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
---
 drivers/acpi/sbs.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c
index 86b7c7975852..4b84b3cd11e3 100644
--- a/drivers/acpi/sbs.c
+++ b/drivers/acpi/sbs.c
@@ -639,10 +639,8 @@ static int acpi_sbs_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	sbs = kzalloc_obj(struct acpi_sbs);
-	if (!sbs) {
-		result = -ENOMEM;
-		goto end;
-	}
+	if (!sbs)
+		return -ENOMEM;
 
 	mutex_init(&sbs->lock);
 
-- 
2.43.0