linux-kernel - Re: [PATCH] clk: meson: meson8b: fix a memory leak in meson8b_clkc_init

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Date:   Fri, 22 Apr 2022 19:25:39 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        xkernel.wang@...mail.com
Cc:     Neil Armstrong <narmstrong@...libre.com>, jbrunet@...libre.com,
        mturquette@...libre.com, khilman@...libre.com,
        p.zabel@...gutronix.de, linux-amlogic@...ts.infradead.org,
        linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clk: meson: meson8b: fix a memory leak in meson8b_clkc_init_common()

Quoting Martin Blumenstingl (2022-04-18 09:39:57)
> Hello,
> 
> first of all: thank you for this patch!
> 
> On Thu, Apr 7, 2022 at 11:28 AM <xkernel.wang@...mail.com> wrote:
> >
> > From: Xiaoke Wang <xkernel.wang@...mail.com>
> >
> > `rstc` is allocated by kzalloc() for resetting the controller register,
> > however, if reset_controller_register() fails, `rstc` is not properly
> > released before returning, which can lead to memory leak.
> > Therefore, this patch adds kfree(rstc) on the above error path.
> In general I am fine with this approach. There's some more "return"
> statements below. Should these be covered as well?

Probably!

> 
> Also a note about meson8b_clkc_init_common() itself: failures in that
> function will result in a non-working system.
> If we can't register the reset controller then most devices won't
> probe and CPU SMP cannot work.
> If registering any clock or the clock controller doesn't work then the
> system also won't work as clocks are not available to other drivers.
> So freeing memory in case of an error is good to have, but the end
> result is still the same: the system won't work.
> 

Can we get far enough to record this fact into either a pstore ramoops
location or the serial console? That would be ideal to make debugging
early problems easier.