linux-kernel - Re: Re: [PATCH] arm/mach-omap2: Fix refcount leak bug in omap

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Message-ID: <YrqaAXkreWHg0MVc@atomide.com>
Date:   Tue, 28 Jun 2022 09:04:49 +0300
From:   Tony Lindgren <tony@...mide.com>
To:     Liang He <windhl@....com>
Cc:     linux@...linux.org.uk, linux-omap@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: Re: [PATCH] arm/mach-omap2: Fix refcount leak bug in omap_hwmod.c

* Liang He <windhl@....com> [220628 05:47]:
> 
> 
> At 2022-06-28 12:57:12, "Tony Lindgren" <tony@...mide.com> wrote:
> >Hi,
> >
> >* Liang He <windhl@....com> [220618 04:43]:
> >> In _init(), of_find_node_by_name() will return a node pointer with
> >> refcount incremented. We should use of_node_put() in fail path or
> >> when it is not used anymore.
> >> 
> >> NOTE: As the ref will be passed from 'bus' to 'np' by the xx_lookup(),
> >> in normal exit path, we should call of_node_put() at the end use of 'np',
> >> not the end use of 'bus'.
> >
> >Looks correct to me. What about missing of_node_put() for
> >of_get_next_child() also in the _init() function?
> >
> >Regards,
> >
> >Tony
> 
> Thanks, Tony.
> 
> I have found this bug but not send the patch for of_get_next_child()
> as I am collecting other OF function related bugs and I have been told that it is better 
> to collect all similar bugs in same directory, then finally report them.

Well in this case while you review a single function, it's usually better
to fix similar issues to avoid having to review the same function multiple
times. Of course if the patch becomes hard to read, then it makes sense
to split it into several patches.

> So I will send a new patch for both of the two missing 'put' bugs caused by
> of_find_xxx() and of_get_xxx() in omap_hwmod.c

Please just update this patch so we have _init() completely reviewed for
similar issues and is not left only partially patched.

Regards,

Tony