[PATCH] acer-wmi: fix memory leaks in wmab_execute error path

[Axel Lin]

When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
the caller must kfree the returned buffer if AE_OK is returned.

Call Trace:
wmab_execute
  -> wmi_evaluate_method
    -> acpi_evaluate_object

Thus if callers of wmab_execute() pass ACPI_ALLOCATE_BUFFER,
the return buffer must be kfreed if wmab_execute return AE_OK.

Signed-off-by: Axel Lin <axel....@gmail.com>
---
 drivers/platform/x86/acer-wmi.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
index 1ea6c43..a158d39 100644
--- a/drivers/platform/x86/acer-wmi.c
+++ b/drivers/platform/x86/acer-wmi.c
@@ -555,6 +555,7 @@ static acpi_status AMW0_find_mailled(void)
        obj->buffer.length == sizeof(struct wmab_ret)) {
                ret = *((struct wmab_ret *) obj->buffer.pointer);
        } else {
+               kfree(out.pointer);
                return AE_ERROR;
        }
 
@@ -598,6 +599,7 @@ static acpi_status AMW0_set_capabilities(void)
        obj->buffer.length == sizeof(struct wmab_ret)) {
                ret = *((struct wmab_ret *) obj->buffer.pointer);
        } else {
+               kfree(out.pointer);
                return AE_ERROR;
        }
 
@@ -607,15 +609,24 @@ static acpi_status AMW0_set_capabilities(void)
        args.ebx = 2 << 8;
        args.ebx |= ACER_AMW0_BLUETOOTH_MASK;
 
+       /*
+        * It's ok to use existing buffer for next wmab_execute call.
+        * But we need to kfree(out.pointer) if next wmab_execute call
+        * returns AE_BUFFER_OVERFLOW.
+        */
        status = wmab_execute(&args, &out);
-       if (ACPI_FAILURE(status))
+       if (ACPI_FAILURE(status)) {
+               if (status == AE_BUFFER_OVERFLOW)
+                       kfree(out.pointer);
                return status;
+       }
 
        obj = (union acpi_object *) out.pointer;
        if (obj && obj->type == ACPI_TYPE_BUFFER
        && obj->buffer.length == sizeof(struct wmab_ret)) {
                ret = *((struct wmab_ret *) obj->buffer.pointer);
        } else {
+               kfree(out.pointer);
                return AE_ERROR;
        }
 
-- 
1.5.4.3



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