Received-SPF: pass (google.com: domain of linux-kernel+bounces-122581-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
Message-ID: <1743ad022502d64042fa7db4d847a988bb90cbdc.camel@sipsolutions.net>
Subject: Re: [PATCH] um: Add winch to winch_handlers before registering
 winch IRQ
From: Johannes Berg <johannes@sipsolutions.net>
To: Roberto Sassu <roberto.sassu@huaweicloud.com>, richard@nod.at, 
	anton.ivanov@cambridgegreys.com
Cc: linux-kernel@vger.kernel.org, linux-um@lists.infradead.org, Roberto
 Sassu <roberto.sassu@huawei.com>
Date: Thu, 28 Mar 2024 09:25:46 +0100
In-Reply-To: <20240307104926.3531358-1-roberto.sassu@huaweicloud.com>
References: <20240307104926.3531358-1-roberto.sassu@huaweicloud.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.50.4 (3.50.4-1.fc39) 
Precedence: bulk
MIME-Version: 1.0

On Thu, 2024-03-07 at 11:49 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu@huawei.com>
>=20
> Registering a winch IRQ is racy, an interrupt may occur before the winch =
is
> added to the winch_handlers list.
>=20
> If that happens, register_winch_irq() adds to that list a winch that is
> scheduled to be (or has already been) freed, causing a panic later in
> winch_cleanup().
>=20
> Avoid the race by adding the winch to the winch_handlers list before
> registering the IRQ, and rolling back if um_request_irq() fails.
>=20

Reviewed-by: Johannes Berg <johannes@sipsolutions.net>

johannes