Messages in this thread Patch in this message | | | Date | Thu, 27 May 2010 14:32:45 +0200 (CEST) | From | Julia Lawall <> | Subject | [PATCH 3/11] arch/sparc/kernel: Eliminate what looks like a NULL pointer dereference |
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From: Julia Lawall <julia@diku.dk>
At the point of the test, action cannot be NULL, as it has been dereferenced in the code just above.
A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/)
// <smpl> @r exists@ expression E,E1; identifier f; statement S1,S2,S3; @@
if ((E == NULL && ...) || ...) { ... when != if (...) S1 else S2 when != E = E1 * E->f ... when any } else S3 // </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
--- arch/sparc/kernel/sun4d_irq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/sparc/kernel/sun4d_irq.c b/arch/sparc/kernel/sun4d_irq.c index ab036a7..e11b461 100644 --- a/arch/sparc/kernel/sun4d_irq.c +++ b/arch/sparc/kernel/sun4d_irq.c @@ -183,7 +183,7 @@ void sun4d_free_irq(unsigned int irq, void *dev_id) goto out_unlock; } - if (action && tmp) + if (tmp) tmp->next = action->next; else *actionp = action->next;
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