linux-kernel - Re: [PATCH] clocksource: fix read and iounmap of incorrect variable

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Date:   Sat, 10 Jun 2017 11:27:00 +0800
From:   Fu Wei <fu.wei@...aro.org>
To:     frowand.list@...il.com
Cc:     Mark Rutland <mark.rutland@....com>,
        Marc Zyngier <marc.zyngier@....com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] clocksource: fix read and iounmap of incorrect variable

Hi Frank,

On 10 June 2017 at 08:26,  <frowand.list@...il.com> wrote:
> From: Frank Rowand <frank.rowand@...y.com>
>
> Fix boot warning 'Trying to vfree() nonexistent vm area'
> from arch_timer_mem_of_init().
>
> Refactored code attempts to read and iounmap using address frame
> instead of address ioremap(frame->cntbase).
>
> Fixes: c389d701dfb70 ("clocksource: arm_arch_timer: split MMIO timer probing.")
>
> Signed-off-by: Frank Rowand <frank.rowand@...y.com>

Reviewed-by: Fu Wei <fu.wei@...aro.org>

> ---
>
> WARNING: CPU: 0 PID: 0 at mm/vmalloc.c:1514 iounmap+0x14/0x18
> Trying to vfree() nonexistent vm area (ee821000)
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.12.0-rc1-dirty #1
> Hardware name: Generic DT based system
> [<c030f574>] (unwind_backtrace) from [<c030b8e0>] (show_stack+0x10/0x14)
> [<c030b8e0>] (show_stack) from [<c05f5204>] (dump_stack+0x6c/0x8c)
> [<c05f5204>] (dump_stack) from [<c031dcdc>] (__warn+0xd0/0xf8)
> [<c031dcdc>] (__warn) from [<c031ddac>] (warn_slowpath_fmt+0x38/0x48)
> [<c031ddac>] (warn_slowpath_fmt) from [<c0315e78>] (iounmap+0x14/0x18)
> [<c0315e78>] (iounmap) from [<c0d36e98>] (arch_timer_mem_of_init+0x224/0x414)
> [<c0d36e98>] (arch_timer_mem_of_init) from [<c0d36868>] (clocksource_probe+0x44/0xa8)
> [<c0d36868>] (clocksource_probe) from [<c0d00ae8>] (start_kernel+0x228/0x3a0)
> [<c0d00ae8>] (start_kernel) from [<0020807c>] (0x20807c)
>
>  drivers/clocksource/arm_arch_timer.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 4bed671e490e..8b5c30062d99 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -1209,9 +1209,9 @@ static int __init arch_timer_of_init(struct device_node *np)
>                 return 0;
>         }
>
> -       rate = readl_relaxed(frame + CNTFRQ);
> +       rate = readl_relaxed(base + CNTFRQ);
>
> -       iounmap(frame);
> +       iounmap(base);

Great thanks for your patch, this is a bug. So sorry for this typo.
It happened in my last v24 patchset: https://lkml.org/lkml/2017/4/14/363

Hope this fix can be merged ASAP.

>
>         return rate;
>  }
> --
> Frank Rowand <frank.rowand@...y.com>
>



-- 
Best regards,

Fu Wei
Software Engineer
Red Hat