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 5CFA825EFA0; Tue, 11 Mar 2025 15:31:54 +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=1741707114; cv=none; b=umjeRsr7BcnKuHT0UhUBkHk3oYiTojjmXBsSzyXRH+J+1Yy8zFLoCYVn9VON/bR//ysJJv6Rpgp0GNACzrO4FnTfj+gSi8CQ2x19moOY8p8KFv+NaQ5ZwO5uG13BVSsPo6J5eyNHnPxpvcEJRt0BxJz+WcMyAlTqXOz9ynCP+g0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741707114; c=relaxed/simple; bh=B8hFl3mLUJb13gTo5B1fAL3jWLcMdCKe2fQ4fiEJ/f4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZoKg+7rMdV8NqQFSJtwBh0NRySfNEAkoyW4rKPIFr1elo58eZt+d+wekdaFuxVvT/MMU8NJ422AOzdhogL7REE0uSe3V3al1wYDIggVpu/Fmz+Aq2q4n96RXXZutVvT7jeYjYbszHO2zBV0MATOG7PVcKDynnpRghH+Vsr5m9iQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=npZCxdoE; 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="npZCxdoE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3BC0C4CEE9; Tue, 11 Mar 2025 15:31:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741707114; bh=B8hFl3mLUJb13gTo5B1fAL3jWLcMdCKe2fQ4fiEJ/f4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=npZCxdoESYFXdRxVDWdxmwebEFdz2I7+rlXoxiNvi/8R5NytLqxuNcgzmX/6TRBbc 239XxXbXY0pHx4FiiCb728kIkXKYoL0NIKya9A4e6iTmKLoqRB8pob0WM73vLpgMN5 3ghUhwpp6T8DADJn2Ll56o570VvwgYC1PjPkKBBE= 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 5.10 247/462] usb: roles: set switch registered flag early on Date: Tue, 11 Mar 2025 15:58:33 +0100 Message-ID: <20250311145808.123185725@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250311145758.343076290@linuxfoundation.org> References: <20250311145758.343076290@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 5.10-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 @@ -345,14 +345,15 @@ 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;