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Date: Tue, 23 Apr 2024 10:11:03 +0200 (CEST)
From: Richard Weinberger <richard@nod.at>
To: Roberto Sassu <roberto.sassu@huaweicloud.com>
Cc: Johannes Berg <johannes@sipsolutions.net>, 
	anton ivanov <anton.ivanov@cambridgegreys.com>, 
	linux-kernel <linux-kernel@vger.kernel.org>, 
	linux-um <linux-um@lists.infradead.org>, 
	Roberto Sassu <roberto.sassu@huawei.com>
Message-ID: <539232323.17201.1713859863502.JavaMail.zimbra@nod.at>
In-Reply-To: <15d5da65079d072856ef5e8d88040df2095bb6b7.camel@huaweicloud.com>
References: <20240307104926.3531358-1-roberto.sassu@huaweicloud.com> <1743ad022502d64042fa7db4d847a988bb90cbdc.camel@sipsolutions.net> <15d5da65079d072856ef5e8d88040df2095bb6b7.camel@huaweicloud.com>
Subject: Re: [PATCH] um: Add winch to winch_handlers before registering
 winch IRQ
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Thread-Topic: Add winch to winch_handlers before registering winch IRQ
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----- Urspr=C3=BCngliche Mail -----
> Von: "Roberto Sassu" <roberto.sassu@huaweicloud.com>
> An: "Johannes Berg" <johannes@sipsolutions.net>, "richard" <richard@nod.a=
t>, "anton ivanov"
> <anton.ivanov@cambridgegreys.com>
> CC: "linux-kernel" <linux-kernel@vger.kernel.org>, "linux-um" <linux-um@l=
ists.infradead.org>, "Roberto Sassu"
> <roberto.sassu@huawei.com>
> Gesendet: Dienstag, 23. April 2024 09:22:31
> Betreff: Re: [PATCH] um: Add winch to winch_handlers before registering w=
inch IRQ

> On Thu, 2024-03-28 at 09:25 +0100, Johannes Berg wrote:
>> 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 win=
ch is
>> > added to the winch_handlers list.
>> >=20
>> > If that happens, register_winch_irq() adds to that list a winch that i=
s
>> > 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
>>=20
>> Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
>=20
> Thank you! Richard, are you going to pick this up?

Yes, it's already in my local queue.

Thanks,
//richard