ACPI: Move dereference after NULL test
authorJulia Lawall <julia@diku.dk>
Sat, 17 Oct 2009 06:34:39 +0000 (08:34 +0200)
committerLen Brown <len.brown@intel.com>
Thu, 5 Nov 2009 22:30:57 +0000 (17:30 -0500)
If the NULL test on pr is needed, then the dereference should be after the
NULL test.

A simplified version of the semantic match that detects this problem is as
follows (http://coccinelle.lip6.fr/):

// <smpl>
@match exists@
expression x, E;
identifier fld;
@@

* x->fld
  ... when != \(x = E\|&x\)
* x == NULL
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
drivers/acpi/processor_throttling.c

index 4c6c14c..1c5d7a8 100644 (file)
@@ -1133,15 +1133,15 @@ int acpi_processor_get_throttling_info(struct acpi_processor *pr)
        int result = 0;
        struct acpi_processor_throttling *pthrottling;
 
+       if (!pr)
+               return -EINVAL;
+
        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
                          pr->throttling.address,
                          pr->throttling.duty_offset,
                          pr->throttling.duty_width));
 
-       if (!pr)
-               return -EINVAL;
-
        /*
         * Evaluate _PTC, _TSS and _TPC
         * They must all be present or none of them can be used.