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 214171D79BE; Wed, 19 Feb 2025 08:36:47 +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=1739954207; cv=none; b=lJQH2WmQu8BR7wxHSm9/N7r9qOlpnBbQrm4vuB06DqzJdO2yYon3/NoVQlar3W709pIXsgq651AVQHYttCWu5Ut6XXhl5lqW1NN1pfi6G5O0nvqzV0B95GGYK2QjWa2o53HOgtf4hIFB3BToPk+GlUMcSQt7HsZW9kTT0/xU1lI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739954207; c=relaxed/simple; bh=euEzCSGv0ToNTZMliFVsxT+v86X8ughUtMEI9AUjU/I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LcgifkF6z8crYUsXiGv9lH2soNDi7mYe9+2cueSTPo/QQsCZDfJ/YmiG1mUavSil5xATUizgwnqOEVOCcaoGsvpTXaoH4kcygDOb3EgaLVJLlioQZOEp+f5LnM3x+EJpZFQv7fNnO8Hn/+K8dKJOpOPcC75QKGA2L3xZizJuGNI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=petNO9jA; 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="petNO9jA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 872E7C4CEE7; Wed, 19 Feb 2025 08:36:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739954206; bh=euEzCSGv0ToNTZMliFVsxT+v86X8ughUtMEI9AUjU/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=petNO9jAadueLozKZxYk2Nmt46hZjmvKbsZ/1dfo/lsmc/Jj2CADnIpYbQvJtFe6G ft5TNQctNfLppVrj+wPFRXfkcRGlIrgXb9vH+pOEBGgBIuUnC6KbLCHjfAL/OUwAhz HPCTiUxmpT87dT9c/w27TcAglf78GT5HiXw0ynnM= 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 6.13 130/274] usb: roles: set switch registered flag early on Date: Wed, 19 Feb 2025 09:26:24 +0100 Message-ID: <20250219082614.698394438@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250219082609.533585153@linuxfoundation.org> References: <20250219082609.533585153@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 6.13-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 @@ -387,8 +387,11 @@ 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); } @@ -399,8 +402,6 @@ usb_role_switch_register(struct device * dev_warn(&sw->dev, "failed to add component\n"); } - sw->registered = true; - /* TODO: Symlinks for the host port and the device controller. */ return sw;