From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sipsolutions.net (s3.sipsolutions.net [168.119.38.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 367E21C288 for ; Thu, 28 Mar 2024 08:25:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=168.119.38.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711614355; cv=none; b=gk9f2PsFpU9J3zfQeCcYThlE+zdWoxAIFfoAUKC6ife6VgDm18JAwcbjaJ+2dEBLU3EwFNQT2E1nuOEMHhgBJ8GeDKXdmMI5w19KGVODj6haLRN++/3hmZKXtmklnmI/+v8JIbGeDRl7snADwV/WYCBsHWySxTps4sk3SjWrZyo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711614355; c=relaxed/simple; bh=xyJ35OeYZ8gYDoCSDvqC+bURigKZ0DrKEJIfJCIxPiA=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=WMUXaiq6Q3s7eQJVMyzHhdQJb8yB2xXH1OdUd1gk4DnqUHx+hyZbB9YdsX/8d/unVYeL8EaUdFnvd2mBvnPnGe1oJW05L6QYf7E/xa9bNcOm/Z1A0r0HqePHrmw8y9Zr8Jvsy6w/4b3ZLU9xJegf5w1/xavzfYKmww8DA9vIM6o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net; spf=pass smtp.mailfrom=sipsolutions.net; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b=vKOostsJ; arc=none smtp.client-ip=168.119.38.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b="vKOostsJ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=xyJ35OeYZ8gYDoCSDvqC+bURigKZ0DrKEJIfJCIxPiA=; t=1711614353; x=1712823953; b=vKOostsJpL7kb+WntTWwPGs3/0Y/OWqW18vvaGyfSYKwY64 auWJQ0UpmDIZAhuw7oaqkJEl0jZHr+B1rjOp3NisNtqVq0lmSI5xwshO3AcRauBkwt+NuY+zF6Ntb qzYtsbSztocAjWr/57Ja4/5ZCx0+tou5TJxmZbe4qMAZNUtK/hxGedG4tHsKUsj5On+bR8B3Lgv0K NSF8/nody1Vv9NLxDPOrz9vY3sicvTBko5MFLZ/vuupq1wgBDk1tVUq8tIdcbbW7fn3paHyjsHG6x RKYVD6S+0/s29ofx7zpvfcYy/UJmLzgjQnIAj1Ho8WqhbVPgLNYYUsuLkvmJYm+Q==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.97) (envelope-from ) id 1rpl51-00000000mV1-3Jg5; Thu, 28 Mar 2024 09:25:47 +0100 Message-ID: <1743ad022502d64042fa7db4d847a988bb90cbdc.camel@sipsolutions.net> Subject: Re: [PATCH] um: Add winch to winch_handlers before registering winch IRQ From: Johannes Berg To: Roberto Sassu , richard@nod.at, anton.ivanov@cambridgegreys.com Cc: linux-kernel@vger.kernel.org, linux-um@lists.infradead.org, Roberto Sassu 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 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-malware-bazaar: not-scanned On Thu, 2024-03-07 at 11:49 +0100, Roberto Sassu wrote: > From: Roberto Sassu >=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