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From: Michal Pecio <michal.pecio@gmail.com>
To: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
Cc: sanan.hasanou@gmail.com, vbabka@suse.cz,
	akpm@linux-foundation.org, cl@gentwo.org, rientjes@google.com,
	roman.gushchin@linux.dev, harry.yoo@oracle.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	syzkaller@googlegroups.com, contact@pgazz.com,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, Dinghao Liu <dinghao.liu@zju.edu.cn>
Subject: Re: WARNING in usb_free_urb
Date: Mon, 29 Jun 2026 09:28:32 +0200	[thread overview]
Message-ID: <20260629092832.355327e7.michal.pecio@gmail.com> (raw)
In-Reply-To: <20260629092033.4a83e91b.michal.pecio@gmail.com>

On Mon, 29 Jun 2026 09:20:33 +0200, Michal Pecio wrote:
> The free(buf[i]) loop should simply be removed. It was mistakenly
> added by d571b592c6206, then a26efd1961a18 recognized the double free
> but attempted to fix it only by changing the order of freeing. Sent
> from .edu domain, so probably an automatic static analyzer fix...

Correction: it failed to recognize the double free, but it fixed a
different (real) problem that the buf array itself was already NULL
and couldn't be scanned for buffer pointers to free.

So it turned this NULL dereferenc into a double free.


  reply	other threads:[~2026-06-29  7:28 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-26 21:27 WARNING in usb_free_urb sanan.hasanou
2026-06-29  6:27 ` Vlastimil Babka (SUSE)
2026-06-29  7:20   ` Michal Pecio
2026-06-29  7:28     ` Michal Pecio [this message]
2026-06-29  7:31     ` Vlastimil Babka (SUSE)
2026-06-29  7:40       ` Hans Verkuil

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