RE: [Uclinux-dist-devel] [PATCH] arch/blackfin: Add kmalloc NULL tests

From: Zhang, Sonic
Date: Mon Jul 13 2009 - 23:15:45 EST


Thanks.

Applied.

Sonic

-----Original Message-----
From: uclinux-dist-devel-bounces@xxxxxxxxxxxxxxxxxxxx
[mailto:uclinux-dist-devel-bounces@xxxxxxxxxxxxxxxxxxxx] On Behalf Of
Julia Lawall
Sent: Monday, July 13, 2009 4:55 PM
To: vapier@xxxxxxxxxx; uclinux-dist-devel@xxxxxxxxxxxxxxxxxxxx;
linux-kernel@xxxxxxxxxxxxxxx; kernel-janitors@xxxxxxxxxxxxxxx
Subject: [Uclinux-dist-devel] [PATCH] arch/blackfin: Add kmalloc NULL
tests

From: Julia Lawall <julia@xxxxxxx>

Check that the result of kmalloc is not NULL before passing it to other
functions.

In the first two cases, the new code returns -ENOMEM, which seems
compatible with what is done for similar functions for other
architectures.

In the last two cases, the new code fails silently, ie just returns,
because the function has void return type.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression *x;
identifier f;
constant char *C;
@@

x = \(kmalloc\|kcalloc\|kzalloc\)(...);
... when != x == NULL
when != x != NULL
when != (x || ...)
(
kfree(x)
|
f(...,C,...,x,...)
|
*f(...,x,...)
|
*x->f
)
// </smpl>

Signed-off-by: Julia Lawall <julia@xxxxxxx>

---
arch/blackfin/mach-common/smp.c | 8 ++++++++
1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/arch/blackfin/mach-common/smp.c
b/arch/blackfin/mach-common/smp.c index 6184005..10dd298 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -211,6 +211,8 @@ int smp_call_function(void (*func)(void *info), void
*info, int wait)
return 0;

msg = kmalloc(sizeof(*msg), GFP_ATOMIC);
+ if (!msg)
+ return -ENOMEM;
INIT_LIST_HEAD(&msg->list);
msg->call_struct.func = func;
msg->call_struct.info = info;
@@ -252,6 +254,8 @@ int smp_call_function_single(int cpuid, void (*func)
(void *info), void *info,
cpu_set(cpu, callmap);

msg = kmalloc(sizeof(*msg), GFP_ATOMIC);
+ if (!msg)
+ return -ENOMEM;
INIT_LIST_HEAD(&msg->list);
msg->call_struct.func = func;
msg->call_struct.info = info;
@@ -287,6 +291,8 @@ void smp_send_reschedule(int cpu)
return;

msg = kmalloc(sizeof(*msg), GFP_ATOMIC);
+ if (!msg)
+ return;
memset(msg, 0, sizeof(msg));
INIT_LIST_HEAD(&msg->list);
msg->type = BFIN_IPI_RESCHEDULE;
@@ -314,6 +320,8 @@ void smp_send_stop(void)
return;

msg = kmalloc(sizeof(*msg), GFP_ATOMIC);
+ if (!msg)
+ return;
memset(msg, 0, sizeof(msg));
INIT_LIST_HEAD(&msg->list);
msg->type = BFIN_IPI_CPU_STOP;
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