re: ACPICA: ACPI 2.0, Interpreter: Fix MLC issues by switching to new TermList grammar for table loading

re: ACPICA: ACPI 2.0, Interpreter: Fix MLC issues by switching to new TermList grammar for table loading

[Dan Carpenter]

Hello Lv Zheng,

The patch 0bfd2f1ec274: "ACPICA: ACPI 2.0, Interpreter: Fix MLC
issues by switching to new TermList grammar for table loading" from
May 13, 2016, leads to the following static checker warning:

	drivers/acpi/acpica/nsparse.c:139 acpi_ns_execute_table()
	error: we previously assumed 'info' could be null (see line 110)

drivers/acpi/acpica/nsparse.c
   135          (void)acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
   136  
   137  cleanup:
   138          acpi_ut_remove_reference(method_obj);
   139          ACPI_FREE(info->full_pathname);
                          ^^^^^^^^^^^^^^^^^^^
Archetypal one err bug.  It's better to unwind in reverse order from how
you allacted things and only free things you have allocated.  Use more
than one label.  Also you can use more descriptive label names.

	(void)acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);

free_pathname:
	ACPI_FREE(info->full_pathname);
free_info:
	ACPI_FREE(info);
remove_method:
	acpi_ut_remove_reference(method_obj);

	return_ACPI_STATUS(status);


   140          info->full_pathname = NULL;
   141          ACPI_FREE(info);
   142          return_ACPI_STATUS(status);
   143  }

regards,
dan carpenter

RE: ACPICA: ACPI 2.0, Interpreter: Fix MLC issues by switching to new TermList grammar for table loading

[Zheng, Lv]

Hi, Dan

Thanks for the report.
I'll double check it with C=2 enabled build.

Best regards
-Lv

> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
> owner@vger.kernel.org] On Behalf Of Dan Carpenter
> Subject: re: ACPICA: ACPI 2.0, Interpreter: Fix MLC issues by switching to
> new TermList grammar for table loading
> 
> Hello Lv Zheng,
> 
> The patch 0bfd2f1ec274: "ACPICA: ACPI 2.0, Interpreter: Fix MLC
> issues by switching to new TermList grammar for table loading" from
> May 13, 2016, leads to the following static checker warning:
> 
> 	drivers/acpi/acpica/nsparse.c:139 acpi_ns_execute_table()
> 	error: we previously assumed 'info' could be null (see line 110)
> 
> drivers/acpi/acpica/nsparse.c
>    135          (void)acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
>    136
>    137  cleanup:
>    138          acpi_ut_remove_reference(method_obj);
>    139          ACPI_FREE(info->full_pathname);
>                           ^^^^^^^^^^^^^^^^^^^
> Archetypal one err bug.  It's better to unwind in reverse order from how
> you allacted things and only free things you have allocated.  Use more
> than one label.  Also you can use more descriptive label names.
> 
> 	(void)acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
> 
> free_pathname:
> 	ACPI_FREE(info->full_pathname);
> free_info:
> 	ACPI_FREE(info);
> remove_method:
> 	acpi_ut_remove_reference(method_obj);
> 
> 	return_ACPI_STATUS(status);
> 
> 
>    140          info->full_pathname = NULL;
>    141          ACPI_FREE(info);
>    142          return_ACPI_STATUS(status);
>    143  }
> 
> regards,
> dan carpenter
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Re: ACPICA: ACPI 2.0, Interpreter: Fix MLC issues by switching to new TermList grammar for table loading

[Dan Carpenter]

On Mon, Jun 06, 2016 at 10:05:12AM +0000, Zheng, Lv wrote:
> Hi, Dan
> 
> Thanks for the report.
> I'll double check it with C=2 enabled build.

It's a Smatch warning.

regards,
dan carpenter

[PATCH] ACPICA: Namespace: Fix wrong cleanup code in acpi_ns_execute_table()

[Lv Zheng]

An error was captured by the static checker. This patch fixes the issue.
introduced in:
  Subject: ACPICA: ACPI 2.0, Interpreter: Fix MLC issues by switching to
           new TermList grammar for table loading

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
---
 drivers/acpi/acpica/nsparse.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpica/nsparse.c b/drivers/acpi/acpica/nsparse.c
index 2452bf3..72893a9 100644
--- a/drivers/acpi/acpica/nsparse.c
+++ b/drivers/acpi/acpica/nsparse.c
@@ -135,10 +135,12 @@ acpi_ns_execute_table(u32 table_index, struct acpi_namespace_node *start_node)
 	(void)acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 
 cleanup:
-	acpi_ut_remove_reference(method_obj);
-	ACPI_FREE(info->full_pathname);
-	info->full_pathname = NULL;
+	if (info) {
+		ACPI_FREE(info->full_pathname);
+		info->full_pathname = NULL;
+	}
 	ACPI_FREE(info);
+	acpi_ut_remove_reference(method_obj);
 	return_ACPI_STATUS(status);
 }
 
-- 
1.7.10