From: Sudeep Holla <sudeep.holla@arm.com>
To: Wen Yang <wenyang@linux.alibaba.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
linux-arm-kernel@lists.infradead.org,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] firmware: arm_scmi: avoid double free in error flow
Date: Mon, 25 Nov 2019 16:13:31 +0000 [thread overview]
Message-ID: <20191125161313.GA1157@bogus> (raw)
In-Reply-To: <20191125155409.9948-1-wenyang@linux.alibaba.com>
On Mon, Nov 25, 2019 at 11:54:09PM +0800, Wen Yang wrote:
> If device_register() fails, both put_device() and kfree()
> are called, ending with a double free of the scmi_dev.
>
Correct.
> Calling kfree() is needed only when a failure happens between the
> allocation of the scmi_dev and its registration, so move it to
> there and remove it from the error flow.
>
kstrdup_const can fail and in that case device is not yet registered,
so we need to free. Since device_register() calls put_device() on failure
too, I would just drop it as it's unnecessary, not sure why I have added
it in the first place. Can you re-spin the patch dropping put_device
and renaming put_dev label to something like free_const.
--
Regards,
Sudeep
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WARNING: multiple messages have this Message-ID (diff)
From: Sudeep Holla <sudeep.holla@arm.com>
To: Wen Yang <wenyang@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Sudeep Holla <sudeep.holla@arm.com>
Subject: Re: [PATCH] firmware: arm_scmi: avoid double free in error flow
Date: Mon, 25 Nov 2019 16:13:31 +0000 [thread overview]
Message-ID: <20191125161313.GA1157@bogus> (raw)
In-Reply-To: <20191125155409.9948-1-wenyang@linux.alibaba.com>
On Mon, Nov 25, 2019 at 11:54:09PM +0800, Wen Yang wrote:
> If device_register() fails, both put_device() and kfree()
> are called, ending with a double free of the scmi_dev.
>
Correct.
> Calling kfree() is needed only when a failure happens between the
> allocation of the scmi_dev and its registration, so move it to
> there and remove it from the error flow.
>
kstrdup_const can fail and in that case device is not yet registered,
so we need to free. Since device_register() calls put_device() on failure
too, I would just drop it as it's unnecessary, not sure why I have added
it in the first place. Can you re-spin the patch dropping put_device
and renaming put_dev label to something like free_const.
--
Regards,
Sudeep
next prev parent reply other threads:[~2019-11-25 16:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-25 15:54 [PATCH] firmware: arm_scmi: avoid double free in error flow Wen Yang
2019-11-25 15:54 ` Wen Yang
2019-11-25 16:13 ` Sudeep Holla [this message]
2019-11-25 16:13 ` Sudeep Holla
2019-11-26 10:24 ` Wen Yang
2019-11-26 10:24 ` Wen Yang
2019-11-26 10:48 ` Sudeep Holla
2019-11-26 10:48 ` Sudeep Holla
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