From: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Yassine Oudjana <yassine.oudjana@gmail.com>,
linux-kernel@vger.kernel.org,
Yassine Oudjana <y.oudjana@protonmail.com>
Subject: Re: [PATCH] regmap-irq: Use the new num_config_regs property in regmap_add_irq_chip_fwnode
Date: Sat, 12 Nov 2022 13:52:35 +0000 [thread overview]
Message-ID: <hXJCiiSHxRbOCrOlFifkWudu1LTcK1TM@localhost> (raw)
In-Reply-To: <166811478949.1075638.10692622037510321259.b4-ty@kernel.org>
Hi Mark,
Mark Brown <broonie@kernel.org> writes:
> On Mon, 7 Nov 2022 23:21:14 +0300, Yassine Oudjana wrote:
>> From: Yassine Oudjana <y.oudjana@protonmail.com>
>>
>> Commit faa87ce9196d ("regmap-irq: Introduce config registers for irq
>> types") added the num_config_regs, then commit 9edd4f5aee84 ("regmap-irq:
>> Deprecate type registers and virtual registers") suggested to replace
>> num_type_reg with it. However, regmap_add_irq_chip_fwnode wasn't modified
>> to use the new property. Later on, commit 255a03bb1bb3 ("ASoC: wcd9335:
>> Convert irq chip to config regs") removed the old num_type_reg property
>> from the WCD9335 driver's struct regmap_irq_chip, causing a null pointer
>> dereference in regmap_irq_set_type when it tried to index d->type_buf as
>> it was never allocated in regmap_add_irq_chip_fwnode:
>>
>> [...]
>
> Applied to
>
> https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git for-next
>
> Thanks!
>
> [1/1] regmap-irq: Use the new num_config_regs property in regmap_add_irq_chip_fwnode
> commit: 84498d1fb35de6ab71bdfdb6270a464fb4a0951b
>
Um, this does prevent the null deref, but the fix is in the wrong place:
d->type_buf shouldn't be accessed in this configuration, the bug is in
regmap_irq_set_type(). The access should be guarded by
"if (d->chip->type_in_mask || d->chip->num_type_reg)" to prevent the
NULL deref.
The analysis in the commit message is inaccurate,
>> However, regmap_add_irq_chip_fwnode wasn't modified to use the
>> new property.
the proposed fix is just wasting memory, since type_buf isn't used
except for the erroneous write -- the write shouldn't happen at all.
Regards,
Aidan
prev parent reply other threads:[~2022-11-12 14:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-07 20:21 [PATCH] regmap-irq: Use the new num_config_regs property in regmap_add_irq_chip_fwnode Yassine Oudjana
2022-11-07 23:58 ` Aidan MacDonald
2022-11-09 18:31 ` Mark Brown
2022-11-10 21:13 ` Mark Brown
2022-11-12 13:52 ` Aidan MacDonald [this message]
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