[PATCH 1/3] kernel/trace/trace.c: introduce missing kfree

From: Julia Lawall
Date: Fri Nov 14 2008 - 13:05:45 EST


From: Julia Lawall <julia@xxxxxxx>

Error handling code following a kzalloc should free the allocated data.

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

// <smpl>
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,l;
position p1,p2;
expression *ptr != NULL;
@@

(
if ((x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...)) == NULL) S
|
x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
)
<... when != x
when != if (...) { <+...x...+> }
x->f = E
...>
(
return \(0\|<+...x...+>\|ptr\);
|
return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>

Signed-off-by: Julia Lawall <julia@xxxxxxx>
---
kernel/trace/trace.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 697eda3..d86e325 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1936,6 +1936,7 @@ __tracing_open(struct inode *inode, struct file *file, int *ret)
ring_buffer_read_finish(iter->buffer_iter[cpu]);
}
mutex_unlock(&trace_types_lock);
+ kfree(iter);

return ERR_PTR(-ENOMEM);
}
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