From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szelinsky.de (szelinsky.de [85.214.127.56]) (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 C52883A962E; Sat, 11 Jul 2026 12:25:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=85.214.127.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783772744; cv=none; b=b8/ElCsx7JufED694pNfSjQNSu7ki5/cbNp80nlMZ3Ku+f+kmwqM0LC5Ia4bL8qxcWi6FVrmMjb8hX2OtrC05FwHjsVqdYfB2282YwcFyGiDlyCGSW63THGdMnpZv2H/s7PAw5J2NRabJreacQqAZe4x/R6cu0agGwhaFEEgu9A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783772744; c=relaxed/simple; bh=1BYD95BQFWbcP4zPI/9XEVAOO2onxu53BCOR+yYThpQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L4wVhpR28VV6fJz25cURZua/x5v1TmDKMMxwEacpnc+wayT9Iu5JE3gNaMRYJbw7rN3S7X0/FW8wmLIQzJiQMD/1sMTl+uWLPP4mhi2ElQzx8RzSD/XymmXcsL0XmwVltAesUeuvP0VVWdLLjt0nhOlvysN5bw/HOXHeYnz0m0U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=szelinsky.de; spf=pass smtp.mailfrom=szelinsky.de; dkim=temperror (0-bit key) header.d=szelinsky.de header.i=@szelinsky.de header.b=DTwS0Wzl; arc=none smtp.client-ip=85.214.127.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=szelinsky.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=szelinsky.de Authentication-Results: smtp.subspace.kernel.org; dkim=temperror (0-bit key) header.d=szelinsky.de header.i=@szelinsky.de header.b="DTwS0Wzl" Received: from localhost (localhost [127.0.0.1]) by szelinsky.de (Postfix) with ESMTP id DF63AE83199; Sat, 11 Jul 2026 14:16:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szelinsky.de; s=mail; t=1783772193; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NNGAV1bh7U8vqoPyuUhn5plMCzTy13ZH6hhnjNoPJyQ=; b=DTwS0WzlusgC+uQHijmG82+3/gRlJ6SvX5R4NELycHK/JP++J0dGzJTDZBx8olk8aQ1SwG 16EM9WOpfCVRl+r4jfzKJr3uIhnr7bVBOlu9KO408qIxlvbbC9jvCgadgLW3TPPTOMav+S jLj+DKxtTO4gWMvUnDG2YhixB3FoGNnrjmb1D6c1zjgpz4LaB+UfdQZUB3Nukdj/bh8sLK brDburN0nw3TjrdgE42U86W3ZTvPjxp6Z7sx9A09rleCVjHPNPl5PKDs5sfGWUn7mueAPE w6yNjyvlOvHon4mAj7D9S1EWZXTHkwBqn5qGJiCK6kwb6g5g9xQmpahECsIVOg== X-Virus-Scanned: Debian amavis at szelinsky.de Received: from szelinsky.de ([127.0.0.1]) by localhost (szelinsky.de [127.0.0.1]) (amavis, port 10025) with ESMTP id 5a25KwGhOgok; Sat, 11 Jul 2026 14:16:33 +0200 (CEST) Received: from p14sgen5.lanhh (dslb-088-070-183-212.088.070.pools.vodafone-ip.de [88.70.183.212]) by szelinsky.de (Postfix) with ESMTPSA; Sat, 11 Jul 2026 14:16:33 +0200 (CEST) From: Carlo Szelinsky To: Oleksij Rempel , Kory Maincent , Andrew Lunn , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Carlo Szelinsky Subject: [PATCH net v2 2/2] net: pse-pd: guard regulator ops against freed PI data during unregister Date: Sat, 11 Jul 2026 14:16:11 +0200 Message-ID: <20260711121611.1639086-3-github@szelinsky.de> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260711121611.1639086-1-github@szelinsky.de> References: <20260711121611.1639086-1-github@szelinsky.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The PSE PI regulators are devm-registered inside pse_controller_register(), which runs before devres_add() arms the controller's own release in devm_pse_controller_register(). On driver detach devres unwinds in LIFO order, so pse_controller_unregister() runs first and frees pcdev->pi via pse_release_pis(); the regulators are torn down afterwards. When regulator_unregister() flushes a pending disable, the regulator core invokes pse_pi_disable(), which dereferences pcdev->pi[id] (directly and via _pse_pi_disable() -> pse_pi_deallocate_pw_budget()). At that point the PI array is already freed, so this is a use-after-free. pse_pi_enable() and pse_pi_is_enabled() dereference pcdev->pi[id] the same way and are reachable by any regulator consumer that keeps a handle across the teardown window. Clear pcdev->pi after freeing it and bail out of the three regulator ops that dereference it when it is NULL. Perform the kfree() and NULL store in pse_release_pis() under pcdev->lock, and read pcdev->pi under the same lock in the ops, so the NULL an op observes is authoritative even when the free runs concurrently on another CPU: the op either sees the live array or returns without touching freed memory. The other three regulator ops (pse_pi_get_voltage(), pse_pi_get_current_limit(), pse_pi_set_current_limit()) do not dereference pcdev->pi and need no guard. Fixes: ffef61d6d273 ("net: pse-pd: Add support for budget evaluation strategies") Signed-off-by: Carlo Szelinsky --- drivers/net/pse-pd/pse_core.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c index 6045b6c399c2..21ccb5146616 100644 --- a/drivers/net/pse-pd/pse_core.c +++ b/drivers/net/pse-pd/pse_core.c @@ -144,7 +144,13 @@ static void pse_release_pis(struct pse_controller_dev *pcdev) of_node_put(pcdev->pi[i].pairset[1].np); of_node_put(pcdev->pi[i].np); } + /* Free under the lock so the NULL store is authoritative against + * the regulator ops that read pcdev->pi under pcdev->lock. + */ + mutex_lock(&pcdev->lock); kfree(pcdev->pi); + pcdev->pi = NULL; + mutex_unlock(&pcdev->lock); } /** @@ -421,6 +427,11 @@ static int pse_pi_is_enabled(struct regulator_dev *rdev) id = rdev_get_id(rdev); mutex_lock(&pcdev->lock); + /* Controller may be unregistered (pcdev->pi freed) mid-teardown. */ + if (!pcdev->pi) { + ret = -ENODEV; + goto out; + } if (pse_pw_d_is_sw_pw_control(pcdev, pcdev->pi[id].pw_d)) { ret = pcdev->pi[id].admin_state_enabled; goto out; @@ -674,6 +685,11 @@ static int pse_pi_enable(struct regulator_dev *rdev) id = rdev_get_id(rdev); mutex_lock(&pcdev->lock); + /* Controller may be unregistered (pcdev->pi freed) mid-teardown. */ + if (!pcdev->pi) { + mutex_unlock(&pcdev->lock); + return -ENODEV; + } if (pse_pw_d_is_sw_pw_control(pcdev, pcdev->pi[id].pw_d)) { /* Manage enabled status by software. * Real enable process will happen if a port is connected. @@ -702,15 +718,20 @@ static int pse_pi_enable(struct regulator_dev *rdev) static int pse_pi_disable(struct regulator_dev *rdev) { struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev); - struct pse_pi *pi; int id, ret; id = rdev_get_id(rdev); - pi = &pcdev->pi[id]; mutex_lock(&pcdev->lock); + /* Reached via the regulator core's deferred-disable flush after + * pcdev->pi is freed on unregister. + */ + if (!pcdev->pi) { + mutex_unlock(&pcdev->lock); + return 0; + } ret = _pse_pi_disable(pcdev, id); if (!ret) - pi->admin_state_enabled = 0; + pcdev->pi[id].admin_state_enabled = 0; mutex_unlock(&pcdev->lock); return 0; -- 2.43.0