From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 875E717A2E8; Mon, 10 Mar 2025 18:00:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741629626; cv=none; b=Lv1zakXoPvS4KMBxCSWrhPLRbq3Ry0J5RP/5+U+AxOlt7nmYppmbz5ty7pLgW/uaulj48aQYitE9whsdrtuo1Iv6tM3Ly8o00OaBrtExaomDUSeiLidfuxP3FCh8UXlMtZkOe4HcheX22BFaSiDmL99JP+f15CKMus1H6fuSWCU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741629626; c=relaxed/simple; bh=SUtUdeaF4ljXG4VQeN80iCOAjxKSpBaShh9xvZsnbsY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FOOZsrGU6uWjUzhnm3/St950v9Bl5CCOuv3Vbj7iQL8jtpb2PU46FsIBAEPuvAX0lU4tQ6U/KH1bYTioceSjssTM/EqOCuqDiOjdw32xvjvWWEe8LqknRqpiBSp3b7aFUj5kP/0nQZi0jqfKTwHWgoOM5Bo+YEkvrwcU2Savcus= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kmDIfjpM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="kmDIfjpM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E67BC4CEE5; Mon, 10 Mar 2025 18:00:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741629626; bh=SUtUdeaF4ljXG4VQeN80iCOAjxKSpBaShh9xvZsnbsY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kmDIfjpMa5vgre3guTwOEuoJYsYIWKlbvuVTENRTaQs/APC0c86t/igOzh4loyurK FwX/736eo9zfBbiZfV5jiDvFL0dElfxYJLtkrjfs++Mq78LXkvUjwLksElTRsTyQQH OivQzLH9o6rNYrUB3YReqYbc0Mc6TSF38mD+vf08= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Elson Roy Serrao , Heikki Krogerus Subject: [PATCH 5.15 360/620] usb: roles: set switch registered flag early on Date: Mon, 10 Mar 2025 18:03:26 +0100 Message-ID: <20250310170559.820052908@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250310170545.553361750@linuxfoundation.org> References: <20250310170545.553361750@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Elson Roy Serrao commit 634775a752a86784511018a108f3b530cc3399a7 upstream. The role switch registration and set_role() can happen in parallel as they are invoked independent of each other. There is a possibility that a driver might spend significant amount of time in usb_role_switch_register() API due to the presence of time intensive operations like component_add() which operate under common mutex. This leads to a time window after allocating the switch and before setting the registered flag where the set role notifications are dropped. Below timeline summarizes this behavior Thread1 | Thread2 usb_role_switch_register() | | | ---> allocate switch | | | ---> component_add() | usb_role_switch_set_role() | | | | | --> Drop role notifications | | since sw->registered | | flag is not set. | | --->Set registered flag.| To avoid this, set the registered flag early on in the switch register API. Fixes: b787a3e78175 ("usb: roles: don't get/set_role() when usb_role_switch is unregistered") Cc: stable Signed-off-by: Elson Roy Serrao Reviewed-by: Heikki Krogerus Link: https://lore.kernel.org/r/20250206193950.22421-1-quic_eserrao@quicinc.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/roles/class.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/usb/roles/class.c +++ b/drivers/usb/roles/class.c @@ -354,14 +354,15 @@ usb_role_switch_register(struct device * dev_set_name(&sw->dev, "%s-role-switch", desc->name ? desc->name : dev_name(parent)); + sw->registered = true; + ret = device_register(&sw->dev); if (ret) { + sw->registered = false; put_device(&sw->dev); return ERR_PTR(ret); } - sw->registered = true; - /* TODO: Symlinks for the host port and the device controller. */ return sw;