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From: Nicolas Palix <npalix@diku.dk>
To: Paul Mackerras <paulus@au.ibm.com>
Subject: [PATCH linux-next] powerpc/pseries: Add missing of_node_put in setup.c
Date: Tue, 2 Dec 2008 14:46:45 +0100
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Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
       Julia Lawall <julia@diku.dk>, Nicolas Palix <npalix@diku.dk>
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of_node_put is needed before discarding a value received from
of_find_node_by_name, eg in error handling code or when the device
node is no longer used.

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

// <smpl>
@r exists@
local idexpression struct device_node *n;
position p1, p2;
statement S1,S2;
expression E,E1;
expression *ptr != NULL;
@@

(
if (!(n@p1 = of_find_node_by_name(...))) S1
|
n@p1 = of_find_node_by_name(...)
)
<... when != of_node_put(n)
    when != if (...) { <+... of_node_put(n) ...+> }
    when != true !n  || ...
    when != n = E
    when != E = n
if (!n || ...) S2
...>
(
  return \(0\|<+...n...+>\|ptr\);
|
return@p2 ...;
|
n = E1
|
E1 = n
)
@script:python@
p1 << r.p1;
p2 << r.p2;
@@

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

Signed-off-by: Nicolas Palix <npalix@diku.dk>
Signed-off-by: Julia Lawall <julia@diku.dk>
---
 arch/powerpc/platforms/pseries/setup.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index ec34170..bbda776 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -237,7 +237,7 @@ static void __init pseries_discover_pic(void)
 						   "interrupt-controller"));) {
 		typep = of_get_property(np, "compatible", NULL);
 		if (strstr(typep, "open-pic")) {
-			pSeries_mpic_node = of_node_get(np);
+			pSeries_mpic_node     = np;
 			ppc_md.init_IRQ       = pseries_mpic_init_IRQ;
 			ppc_md.get_irq        = mpic_get_irq;
 			setup_kexec_cpu_down_mpic();
@@ -247,6 +247,7 @@ static void __init pseries_discover_pic(void)
 			ppc_md.init_IRQ       = pseries_xics_init_IRQ;
 			setup_kexec_cpu_down_xics();
 			smp_init_pseries_xics();
+			of_node_put(np);
 			return;
 		}
 	}
-- 
Nicolas Palix
--
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