From: Maxime Ripard <maxime@cerno.tech>
To: Andre Przywara <andre.przywara@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Chen-Yu Tsai <wens@csie.org>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
Icenowy Zheng <icenowy@aosc.io>,
linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-sunxi@lists.linux.dev
Subject: Re: [PATCH] pinctrl: sunxi: Don't underestimate number of functions
Date: Thu, 22 Jul 2021 16:09:42 +0200 [thread overview]
Message-ID: <20210722140942.2ew6htf5kmvpldsm@gilmour> (raw)
In-Reply-To: <20210722132548.22121-1-andre.przywara@arm.com>
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On Thu, Jul 22, 2021 at 02:25:48PM +0100, Andre Przywara wrote:
> When we are building all the various pinctrl structures for the
> Allwinner pinctrl devices, we do some estimation about the maximum
> number of distinct function (names) that we will need.
>
> So far we take the number of pins as an upper bound, even though we
> can actually have up to four special functions per pin. This wasn't a
> problem until now, since we indeed have typically far more pins than
> functions, and most pins share common functions.
>
> However the H616 "-r" pin controller has only two pins, but four
> functions, so we run over the end of the array when we are looking for
> a matching function name in sunxi_pinctrl_add_function - there is no
> NULL sentinel left that would terminate the loop:
>
> [ 8.200648] Unable to handle kernel paging request at virtual address fffdff7efbefaff5
> [ 8.209179] Mem abort info:
> ....
> [ 8.368456] Call trace:
> [ 8.370925] __pi_strcmp+0x90/0xf0
> [ 8.374559] sun50i_h616_r_pinctrl_probe+0x1c/0x28
> [ 8.379557] platform_probe+0x68/0xd8
>
> Do an actual worst case allocation (4 functions per pin, three common
> functions and the sentinel) for the initial array allocation. This is
> now heavily overestimating the number of functions in the common case,
> but we will reallocate this array later with the actual number of
> functions, so it's only temporarily.
>
> Fixes: 561c1cf17c46 ("pinctrl: sunxi: Add support for the Allwinner H616-R pin controller")
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Thanks!
Maxime
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next prev parent reply other threads:[~2021-07-22 14:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-22 13:25 [PATCH] pinctrl: sunxi: Don't underestimate number of functions Andre Przywara
2021-07-22 14:09 ` Maxime Ripard [this message]
2021-08-10 12:55 ` Linus Walleij
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