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 602EB1C2432; Wed, 19 Feb 2025 09:00:10 +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=1739955610; cv=none; b=d6GT4R48nf7nAftkoYH/5u7A9CDbTM/RsGgfMFquGNccuKn/2mNVdyCVPWTvPKLQS56/km1Olkegb/6r00Zm4dw1JTHr+UTZPetDNSdPgNehdObyUtCEOU0G93g0PMb2IFkU5IDrSRG68yp8wndYA23gj/uwEvorFN0iomEwR88= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739955610; c=relaxed/simple; bh=3AB7F6tm0HRiXaQZUTlAEPjtW+PUbp8nHiaK9KOkceA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FmH5CeWlZ/LcEJnEPVcIHm3PcpBJRbiIAKBR6+Vy3wXXeYu8xNjLfzQ6ZhYbvbOS0uvF8LVwpDcYZpXuPqEZ0gKVGWZ8NbzxWe6L8MfXTfZiSMU/uQI2bwJ6Cea0HRUsPet2NngUBT2TcgtgzAxen37t/DBkldjlHrKofW0UOl0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=eqwKUuCE; 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="eqwKUuCE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4A54C4CEE6; Wed, 19 Feb 2025 09:00:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739955610; bh=3AB7F6tm0HRiXaQZUTlAEPjtW+PUbp8nHiaK9KOkceA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eqwKUuCE/Z1NWn0raOSeZsrxyy1rI7XaMHG6ut2Mp1Op5OLQWfKDtLUbvOD/GroCn gMOQIgp+78P1ggdHnJF/4hmh6eE1TyL8RmtlwsfA6BIHPs1ykLjfiZS8Z5mrsXFRzn 8qhJox7jsThmJdjJdCa3DjHIwJfXroNPsgBD9xuM= 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 6.6 058/152] usb: roles: set switch registered flag early on Date: Wed, 19 Feb 2025 09:27:51 +0100 Message-ID: <20250219082552.341942080@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250219082550.014812078@linuxfoundation.org> References: <20250219082550.014812078@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-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 @@ -355,14 +355,15 @@ 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;