From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 42D8A538D68 for ; Wed, 9 Sep 2026 11:03:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788951843; cv=none; b=sFZDPSP2iDQv4qD9VS8Z1Kmsh3njZoIWD7MIjJnQk+i3f3PaAoA/nRpCtLI4zG7k8Wwfw7zxCmRduDBO3oV257bchBPNWExwSd21YDrNvfKiyGxJsqvoRj6T5kleTiYC0uIGNCrB0qkVRG8qqHe4tH8vn3MDzvws2H8Y+ldcBmA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788951843; c=relaxed/simple; bh=ekOmJ/Pxpor6drkFOY8VwP8zxQ+suVgbLtDAJ2TEic8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=n0HeH+Y652a6YbyZn9PqV7H/gH1I+HlvURYuFE+RJHZ/MmFbtLR7GzmkL/4/v4eAf8c7yxr9O7ID4RLqhG+IE74v2yOc4q93NdHPxpA2OmlOhJKria0oqAYrOpBPBcJCGauQfjLBC9BStc6nZJ0MB638I+VtIjhlyn9SaIwc/XU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GsyVCrLZ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GsyVCrLZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9A451F00A3A; Wed, 9 Sep 2026 11:03:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788951835; bh=p6Jauh7qjFjMT3oDR8EeQ5p3ozQD3EHpynZckpJY6nA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GsyVCrLZaqgVOwj6nr20ryorPVX6HUyO8xVO+FOj+nxotbyhiqTxm3+Ca09u3h03H 7eMApRP7Qrj3pPmHXq5j8xjeD07echK95/QjWmE090jH6gRLOmGs51JgLYJzP3hoik OupZyliuRO16E0dXK67Ra3xWx1dfSjEjxSG+tvDywfmcKdeCUXP2JoHtxFtrSo1bIY sw8av3dloelzC+49XSXa1lcgZ6vjnHnUC9NzNPae4Scr1zJMdGWa70mAvpzUw71icE EXRfqKb72K23mtfswKc7pRiRO0V3c4JnBU1zAa2W1w5jnKoWfCR+Rs5vPBr2slUw38 HVqZKOm9LGRyA== From: Sasha Levin To: stable@vger.kernel.org Cc: Fan Wu , Sebastian Reichel , Sasha Levin Subject: [PATCH 5.15.y 2/2] power: supply: charger-manager: register regulators before exposing sysfs Date: Wed, 9 Sep 2026 07:03:52 -0400 Message-ID: <20260909110352.1705903-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260909110352.1705903-1-sashal@kernel.org> References: <2026090321-dosage-uproar-b130@gregkh> <20260909110352.1705903-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Fan Wu [ Upstream commit c57cb36f76eb7ced45f57af1a890d8f3a6d76342 ] charger_manager_remove() and the err_reg_extcon probe error path free each charger regulator with regulator_put() before tearing down the power_supply sysfs entries (power_supply_unregister()). charger_manager_remove() also calls try_charger_enable(cm, false) after the regulator_put() loop. A concurrent write to a charger's externally_control sysfs attribute that lands between regulator_put() and power_supply_unregister() can run charger_externally_control_store() and call try_charger_enable(), which, when charging is enabled, dereferences the already-freed consumer handle. When charging is enabled, try_charger_enable(cm, false) in .remove() also dereferences the freed handles directly. Both leave use-after-free windows. Symmetrically, probe registers the sysfs entries (power_supply_register) before acquiring the regulators (regulator_get, inside charger_manager_register_extcon), so userspace can reach externally_control before the regulators are available. Split charger_manager_register_extcon() on the sync/async boundary: charger_manager_get_regulators() (regulator_get only, no async producer) now runs before power_supply_register() so sysfs is not live before regulators are available, and charger_manager_register_extcon() keeps only the extcon notifier/work setup, still after power_supply_register() so a power_supply_register() failure cannot reach extcon setup. This keeps the sysfs setup/teardown ordering symmetric without introducing an asynchronous producer on the earlier probe-error path. Move power_supply_unregister() and try_charger_enable(cm, false) ahead of the regulator_put() loop on both teardown paths, and adjust err_reg_extcon (power_supply_unregister() then fall through err_regulator for regulator_put(); get_regulators self-rolls back on its own failure). This does not address the separate extcon-notifier-driven deref of the same handles, which needs its own synchronization design. Found by an in-house static analysis tool. Fixes: 3950c7865cd7 ("charger-manager: Add support sysfs entry for charger") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu Link: https://patch.msgid.link/20260728030123.230202-1-fanwu01@zju.edu.cn Signed-off-by: Sebastian Reichel Signed-off-by: Sasha Levin --- drivers/power/supply/charger-manager.c | 54 +++++++++++++++++++------- 1 file changed, 39 insertions(+), 15 deletions(-) diff --git a/drivers/power/supply/charger-manager.c b/drivers/power/supply/charger-manager.c index a20e7aaffbaa8..7f7ddecf2250b 100644 --- a/drivers/power/supply/charger-manager.c +++ b/drivers/power/supply/charger-manager.c @@ -1017,6 +1017,29 @@ static int charger_extcon_init(struct charger_manager *cm, return 0; } +static int charger_manager_get_regulators(struct charger_manager *cm) +{ + struct charger_desc *desc = cm->desc; + struct charger_regulator *charger; + int i, ret; + + for (i = 0; i < desc->num_charger_regulators; i++) { + charger = &desc->charger_regulators[i]; + charger->consumer = regulator_get(cm->dev, + charger->regulator_name); + if (IS_ERR(charger->consumer)) { + dev_err(cm->dev, "Cannot find charger(%s)\n", + charger->regulator_name); + ret = PTR_ERR(charger->consumer); + while (i-- > 0) + regulator_put(desc->charger_regulators[i].consumer); + return ret; + } + charger->cm = cm; + } + return 0; +} + /** * charger_manager_register_extcon - Register extcon device to receive state * of charger cable. @@ -1039,15 +1062,6 @@ static int charger_manager_register_extcon(struct charger_manager *cm) for (i = 0; i < desc->num_charger_regulators; i++) { charger = &desc->charger_regulators[i]; - charger->consumer = regulator_get(cm->dev, - charger->regulator_name); - if (IS_ERR(charger->consumer)) { - dev_err(cm->dev, "Cannot find charger(%s)\n", - charger->regulator_name); - return PTR_ERR(charger->consumer); - } - charger->cm = cm; - for (j = 0; j < charger->num_cables; j++) { struct charger_cable *cable = &charger->cables[j]; @@ -1582,13 +1596,23 @@ static int charger_manager_probe(struct platform_device *pdev) } psy_cfg.attr_grp = desc->sysfs_groups; + /* + * Acquire charger regulators before exposing the sysfs entries, so + * userspace cannot reach externally_control before the regulators + * (and charger->cm) are available. Mirrors the order in remove(). + */ + ret = charger_manager_get_regulators(cm); + if (ret < 0) + return ret; + cm->charger_psy = power_supply_register(&pdev->dev, &cm->charger_psy_desc, &psy_cfg); if (IS_ERR(cm->charger_psy)) { dev_err(&pdev->dev, "Cannot register charger-manager with name \"%s\"\n", cm->charger_psy_desc.name); - return PTR_ERR(cm->charger_psy); + ret = PTR_ERR(cm->charger_psy); + goto err_regulator; } /* Register extcon device for charger cable */ @@ -1622,11 +1646,11 @@ static int charger_manager_probe(struct platform_device *pdev) return 0; err_reg_extcon: + power_supply_unregister(cm->charger_psy); +err_regulator: for (i = 0; i < desc->num_charger_regulators; i++) regulator_put(desc->charger_regulators[i].consumer); - power_supply_unregister(cm->charger_psy); - return ret; } @@ -1644,12 +1668,12 @@ static void charger_manager_remove(struct platform_device *pdev) cancel_work_sync(&setup_polling); cancel_delayed_work_sync(&cm_monitor_work); - for (i = 0 ; i < desc->num_charger_regulators ; i++) - regulator_put(desc->charger_regulators[i].consumer); + try_charger_enable(cm, false); power_supply_unregister(cm->charger_psy); - try_charger_enable(cm, false); + for (i = 0 ; i < desc->num_charger_regulators ; i++) + regulator_put(desc->charger_regulators[i].consumer); } static const struct platform_device_id charger_manager_id[] = { -- 2.53.0