Re: [cocci] Searching for missing cleanup function calls (with SmPL)?

[Markus Elfring <Markus.Elfring@web.de>]

> But if there are cases where dn really should be freed, that could be
> something to write a patch for.

I would like to clarify possible software development consequences
also according to a diff output like the following.

Markus_Elfring@Sonne:…/Projekte/Linux/next-analyses> time /usr/bin/spatch …/Projekte/Coccinelle/janitor/show_missing_of_node_put.cocci arch/powerpc/sysdev/fsl_rio.c
…
@@ -511,7 +511,6 @@ static int fsl_rio_setup(struct platform
        }
 
        /*set up doobell node*/
-       np = of_find_compatible_node(NULL, NULL, "fsl,srio-dbell-unit");
        if (!np) {
                dev_err(&dev->dev, "No fsl,srio-dbell-unit node\n");
                rc = -ENODEV;
@@ -537,7 +536,6 @@ static int fsl_rio_setup(struct platform
                                (u32)range_start);
 
        /*set up port write node*/
-       np = of_find_compatible_node(NULL, NULL, "fsl,srio-port-write-unit");
        if (!np) {
                dev_err(&dev->dev, "No fsl,srio-port-write-unit node\n");
                rc = -ENODEV;

real    0m0,968s
user    0m0,547s
sys     0m0,059s


I would expect that the previously mentioned SmPL code “... when != dn”
should exclude some C source code.
How does the shown test result fit to this expectation on the behaviour
of the Coccinelle software (when there are obviously places where the found variable
is used again after a null pointer check)?


But it seems that the code is still improvable.
https://elixir.bootlin.com/linux/v6.17-rc5/source/arch/powerpc/sysdev/fsl_rio.c#L439-L731

I guess that of_node_put() should be called before the affected variable
is reassigned here.
https://elixir.bootlin.com/linux/v6.17-rc5/source/drivers/of/base.c#L1011-L1022

I would appreciate your advice.

Regards,
Markus