linux-kernel - Re: [PATCH] mfd: stmfx: Uninitialized variable in stmfx_irq

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Date:   Mon, 3 Jun 2019 09:12:04 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Dan Carpenter <dan.carpenter@...cle.com>
Cc:     Amelie Delaunay <amelie.delaunay@...com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        linux-stm32@...md-mailman.stormreply.com,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] mfd: stmfx: Uninitialized variable in stmfx_irq_handler()

On Wed, 15 May 2019, Dan Carpenter wrote:

> The problem is that on 64bit systems then we don't clear the higher
> bits of the "pending" variable.  So when we do:
> 
> 	ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
> 	if (ack) {
> 
> the if (ack) condition relies on uninitialized data.  The fix it that
> I've changed "pending" from an unsigned long to a u32.  I changed "n" as
> well, because that's a number in the 0-10 range and it fits easily
> inside an int.  We do need to add a cast to "pending" when we use it in
> the for_each_set_bit() loop, but that doesn't cause a proble, it's
> fine.
> 
> Fixes: 06252ade9156 ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> ---
>  drivers/mfd/stmfx.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Could do with an author's Ack here.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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