[PATCH 2/2] ARM: imx: fix device_node refcount leaks in imx7_src_init()

[Weigang He]

imx7_src_init() obtains two device_node references via
of_find_compatible_node() - one for "fsl,imx7d-src" and one for
"fsl,imx7d-gpc" - reusing the same np variable, but never calls
of_node_put() on either. On every i.MX7D boot up to two device_node
refcounts are leaked:

  - The "fsl,imx7d-src" node is leaked both when of_iomap() fails (the
    early return after the mapping) and when it succeeds, because np is
    then overwritten by the second of_find_compatible_node() call
    without releasing the prior reference.
  - The "fsl,imx7d-gpc" node is leaked on every path leaving the
    function after it is acquired.

Release each reference immediately after of_iomap() consumes the node.
of_iomap() maps the node's registers but does not retain a reference to
the device_node, so it is safe to put the node once mapped; this also
drops the first reference before np is reused for the second lookup.

Found by static analysis tool CodeQL.

Fixes: e34645f45805 ("ARM: imx: add smp support for imx7d")
Signed-off-by: Weigang He <geoffreyhe2@xxxxxxxxx>
---
 arch/arm/mach-imx/src.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/mach-imx/src.c b/arch/arm/mach-imx/src.c
index f28bfb653a88f..c3c80b4c3d53b 100644
--- a/arch/arm/mach-imx/src.c
+++ b/arch/arm/mach-imx/src.c
@@ -196,6 +196,7 @@ void __init imx7_src_init(void)
 		return;
 
 	src_base = of_iomap(np, 0);
+	of_node_put(np);
 	if (!src_base)
 		return;
 
@@ -204,6 +205,7 @@ void __init imx7_src_init(void)
 		return;
 
 	gpc_base = of_iomap(np, 0);
+	of_node_put(np);
 	if (!gpc_base)
 		return;
 }
-- 
2.43.0