From: Takashi Iwai <tiwai@suse.de>
To: Xu Wang <vulab@iscas.ac.cn>
Cc: perex@perex.cz, tiwai@suse.com, alexander@tsoy.me,
e.burema@gmail.com, alsa-devel@alsa-project.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ALSA: usb-audio: endpoint : remove redundant check before usb_free_coherent()
Date: Thu, 04 Feb 2021 07:40:35 +0100 [thread overview]
Message-ID: <s5him788hek.wl-tiwai@suse.de> (raw)
In-Reply-To: <20210204020518.76619-1-vulab@iscas.ac.cn>
On Thu, 04 Feb 2021 03:05:18 +0100,
Xu Wang wrote:
>
> usb_free_coherent() is safe with NULL addr and this check is
> not required.
The check there isn't about NULL buffer or not; instead it checks
whether the buffer was allocated for each or it shares the single
buffer (for sync endpoints). In the latter case, your patch will lead
to double-free.
thanks,
Takashi
prev parent reply other threads:[~2021-02-04 6:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 2:05 [PATCH] ALSA: usb-audio: endpoint : remove redundant check before usb_free_coherent() Xu Wang
2021-02-04 6:40 ` Takashi Iwai [this message]
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