[PATCH 5/14] drivers/acpi: Move dereference after NULL test

From: Julia Lawall
Date: Sat Oct 17 2009 - 02:34:46 EST


From: Julia Lawall <julia@xxxxxxx>

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@xxxxxxx>

---
drivers/acpi/processor_throttling.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 4c6c14c..1c5d7a8 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -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.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/