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 1754B3D3336; Mon, 27 Apr 2026 14:00:01 +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=1777298401; cv=none; b=O0bguzkG940GhwRdJrsbAHzLdlCpF1r0182MP+ceFw0OUgxlYM/zW/yBoSQNSJijRvRocXI29KEVlyvGBB0oBVsO5lqYIxGaFdvA99yI4ya12T7KyJQm56K8f4YE/0l0D3ZzWpGJuz2a8tcLCk7gpRoLVEYZi020tvAQ90HzRgA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777298401; c=relaxed/simple; bh=x6GmU/uqEIoUvn9KjuCPHep4bsxmmEYRRG84/GahgL0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=InZCeLAGhmssYNpxTXpIidNbETouGVe1jzvu1OVanz+71Pcvulx2VaFuwmMcOqFL+CG+63t0nV7V+ooXUbfv698iq8b1RI/t5TVSxigz+blS2xJhSyMBiwEBPPHwXMgLhqsRocT15e/1yCxzO4QjBfDf5q2jU8PEutKVir8/rYo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nkOkoMTR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nkOkoMTR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16742C19425; Mon, 27 Apr 2026 13:59:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777298400; bh=x6GmU/uqEIoUvn9KjuCPHep4bsxmmEYRRG84/GahgL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nkOkoMTRHVCkA5WFAQmObDCR+rqha3Ftt3wJjJTI/MQ6kwjp8XW6LNb7PHNykkDDt sb1l7kugIdIYj3kJdkSeJz5tl39oZFvybZWs2CGeTZhExvGTMk7+quMiqa6Ou7xPst qCnygcj4axMm14JxmHe+4lXiJJ/HVsiXOvpvwJUhMiNYi7tXu5wbxR3RYluscivoPk /YjXj3ZE/64xA35kSaT0mCu2jN6F9S/lRSjxhZwRZ4E0AVeExOVuuVyHs1QtneuPS3 jIkXMdEl8AJTWAIecHR/o7AobqxVwkSqIuC22LFahuyg6JB69t4oPmaD9OkrfaH+Fp 0daaVWaz8OYaw== From: Tzung-Bi Shih To: Arnd Bergmann , Greg Kroah-Hartman , Bartosz Golaszewski , Linus Walleij Cc: Benson Leung , tzungbi@kernel.org, linux-kernel@vger.kernel.org, chrome-platform@lists.linux.dev, driver-core@lists.linux.dev, linux-doc@vger.kernel.org, linux-gpio@vger.kernel.org, "Rafael J. Wysocki" , Danilo Krummrich , Jonathan Corbet , Shuah Khan , Laurent Pinchart , Wolfram Sang , Jason Gunthorpe , Johan Hovold , "Paul E . McKenney" , Dan Williams Subject: [PATCH v9 8/9] platform/chrome: Protect cros_ec_device lifecycle with revocable Date: Mon, 27 Apr 2026 21:58:40 +0800 Message-ID: <20260427135841.96266-9-tzungbi@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260427135841.96266-1-tzungbi@kernel.org> References: <20260427135841.96266-1-tzungbi@kernel.org> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The cros_ec_device can be unregistered when the underlying device is removed. Other kernel drivers that interact with the EC may hold a pointer to the cros_ec_device, creating a risk of a use-after-free error if the EC device is removed while still being referenced. To prevent this, leverage the revocable and convert the underlying device drivers to resource providers of cros_ec_device. Signed-off-by: Tzung-Bi Shih --- v9: - New to the series. - Change revocable API usages accordingly. - Rename "revocable_provider" -> "its_rev". v5 - v8: - Doesn't exist. v4: https://lore.kernel.org/all/20250923075302.591026-5-tzungbi@kernel.org - No changes. v3: https://lore.kernel.org/all/20250912081718.3827390-5-tzungbi@kernel.org - Initialize the revocable provider in cros_ec_device_alloc() instead of spreading in protocol device drivers. v2: https://lore.kernel.org/all/20250820081645.847919-5-tzungbi@kernel.org - Rename "ref_proxy" -> "revocable". v1: https://lore.kernel.org/all/20250814091020.1302888-3-tzungbi@kernel.org --- drivers/platform/chrome/cros_ec.c | 11 +++++++++++ include/linux/platform_data/cros_ec_proto.h | 3 +++ 2 files changed, 14 insertions(+) diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c index 1da79e3d215b..2702a1bbfeb5 100644 --- a/drivers/platform/chrome/cros_ec.c +++ b/drivers/platform/chrome/cros_ec.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -37,6 +38,7 @@ static void cros_ec_device_free(void *data) mutex_destroy(&ec_dev->lock); lockdep_unregister_key(&ec_dev->lockdep_key); + revocable_revoke(ec_dev->its_rev); } struct cros_ec_device *cros_ec_device_alloc(struct device *dev) @@ -47,6 +49,15 @@ struct cros_ec_device *cros_ec_device_alloc(struct device *dev) if (!ec_dev) return NULL; + ec_dev->its_rev = revocable_alloc(ec_dev); + if (!ec_dev->its_rev) + return NULL; + /* + * Drop the extra reference for the caller as the caller is the + * resource provider. + */ + revocable_put(ec_dev->its_rev); + ec_dev->din_size = sizeof(struct ec_host_response) + sizeof(struct ec_response_get_protocol_info) + EC_MAX_RESPONSE_OVERHEAD; diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h index de14923720a5..e8c3bd03403c 100644 --- a/include/linux/platform_data/cros_ec_proto.h +++ b/include/linux/platform_data/cros_ec_proto.h @@ -12,6 +12,7 @@ #include #include #include +#include #include @@ -165,6 +166,7 @@ struct cros_ec_command { * @pd: The platform_device used by the mfd driver to interface with the * PD behind an EC. * @panic_notifier: EC panic notifier. + * @its_rev: The revocable_provider to this device. */ struct cros_ec_device { /* These are used by other drivers that want to talk to the EC */ @@ -211,6 +213,7 @@ struct cros_ec_device { struct platform_device *pd; struct blocking_notifier_head panic_notifier; + struct revocable *its_rev; }; /** -- 2.51.0