From patchwork Mon Nov 18 11:23:15 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rasmus Villemoes X-Patchwork-Id: 1196766 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 47Gq6z4qVQz9sQp for ; Tue, 19 Nov 2019 00:09:47 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=rasmusvillemoes.dk Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=rasmusvillemoes.dk header.i=@rasmusvillemoes.dk header.b="Da5Kawzy"; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47Gq6z3qCJzDqB7 for ; Tue, 19 Nov 2019 00:09:47 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=rasmusvillemoes.dk (client-ip=2a00:1450:4864:20::343; helo=mail-wm1-x343.google.com; envelope-from=linux@rasmusvillemoes.dk; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=rasmusvillemoes.dk Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=rasmusvillemoes.dk header.i=@rasmusvillemoes.dk header.b="Da5Kawzy"; dkim-atps=neutral Received: from mail-wm1-x343.google.com (mail-wm1-x343.google.com [IPv6:2a00:1450:4864:20::343]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47GmnV1tjmzDqPn for ; Mon, 18 Nov 2019 22:24:30 +1100 (AEDT) Received: by mail-wm1-x343.google.com with SMTP id q70so16936162wme.1 for ; Mon, 18 Nov 2019 03:24:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=KgiJMcSuN2IAx9Zm1/LolJRzS4II+K1np/uTCuIzrY4=; b=Da5Kawzye9nyinII5RcMGqIuWzaAHWpv8eWE10YEgTbOS2e7pdA1XEymDYI7XSx+Oy oU+qEkQDsm+hUgEwTwbTVoXCqcpxvJLWUl/oy2ljyegaTwrtwexyGLRkkdd1lWFbrLoG 20iK32zcAbZlor6bFpAzxEtWoAzNhktt+/apI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=KgiJMcSuN2IAx9Zm1/LolJRzS4II+K1np/uTCuIzrY4=; b=sXeudyIxZaKKAcylFRzQ15N9VvL8TWIZxVgeQjJ3ElZ1IorPcjz455re9fIIUO6MmY 64B8O5eS5EIuPYUGk8I10AQDKpeZ7RcChvKpSmYsd+xcH1RGjfJJJ2mIeI4Eoihe05PT Q5Nh2zkv/CgUevfhAKsOo+yfImlRzZQWQUxoLx22TOg/0Ca0aj9xCl4j6T2oj7U73K1b qjPjHS2wegRiFEFN0hp+QDykCcpQ6YoQclSNbRl5uqMFJeZT5KEAU1u/hyaZwix+P0GT LeEvddljGUK7hwj3CfGG5z9hJ2FXnh2CIwRLD/KMPTyvKCMirmZwTf84Kj8VGDcymCTl Y1fA== X-Gm-Message-State: APjAAAWJJGfMD+fx2iJXL5zeXbg31wTwP1Bv2H+K+IkrwjI9DopISeYv qd6DhwEPOUjLsfvRiAXcY+BAKg== X-Google-Smtp-Source: APXvYqx+sxov+O09urgAEctG0UgafcxBahdIb2LRrufCvHUYipe4rzdjWcB17x3lyxf+DQyswtdBig== X-Received: by 2002:a05:600c:2054:: with SMTP id p20mr29850985wmg.177.1574076263632; Mon, 18 Nov 2019 03:24:23 -0800 (PST) Received: from prevas-ravi.prevas.se (ip-5-186-115-54.cgn.fibianet.dk. [5.186.115.54]) by smtp.gmail.com with ESMTPSA id y2sm21140815wmy.2.2019.11.18.03.24.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Nov 2019 03:24:23 -0800 (PST) From: Rasmus Villemoes To: Qiang Zhao , Li Yang , Christophe Leroy Subject: [PATCH v5 39/48] soc: fsl: qe: refactor cpm_muram_alloc_common to prevent BUG on error path Date: Mon, 18 Nov 2019 12:23:15 +0100 Message-Id: <20191118112324.22725-40-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191118112324.22725-1-linux@rasmusvillemoes.dk> References: <20191118112324.22725-1-linux@rasmusvillemoes.dk> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Timur Tabi , Rasmus Villemoes , linux-kernel@vger.kernel.org, Scott Wood , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" If the kmalloc() fails, we try to undo the gen_pool allocation we've just done. Unfortunately, start has already been modified to subtract the GENPOOL_OFFSET bias, so we're freeing something that very likely doesn't exist in the gen_pool, meaning we hit the kernel BUG at lib/genalloc.c:399! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM ... [<803fd0e8>] (gen_pool_free) from [<80426bc8>] (cpm_muram_alloc_common+0xb0/0xc8) [<80426bc8>] (cpm_muram_alloc_common) from [<80426c28>] (cpm_muram_alloc+0x48/0x80) [<80426c28>] (cpm_muram_alloc) from [<80428214>] (ucc_slow_init+0x110/0x4f0) [<80428214>] (ucc_slow_init) from [<8044a718>] (qe_uart_request_port+0x3c/0x1d8) (this was tested by just injecting a random failure by adding "|| (get_random_int()&7) == 0" to the "if (!entry)" condition). Refactor the code so we do the kmalloc() first, meaning that's the thing that needs undoing in case gen_pool_alloc_algo() then fails. This allows a later cleanup to move the locking from the callers into the _common function, keeping the kmalloc() out of the critical region and then, hopefully (if all the muram_alloc callers allow) change it to a GFP_KERNEL allocation. Signed-off-by: Rasmus Villemoes --- drivers/soc/fsl/qe/qe_common.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/drivers/soc/fsl/qe/qe_common.c b/drivers/soc/fsl/qe/qe_common.c index dcb267567d76..a81a1a79f1ca 100644 --- a/drivers/soc/fsl/qe/qe_common.c +++ b/drivers/soc/fsl/qe/qe_common.c @@ -119,23 +119,21 @@ static s32 cpm_muram_alloc_common(unsigned long size, struct muram_block *entry; s32 start; + entry = kmalloc(sizeof(*entry), GFP_ATOMIC); + if (!entry) + return -ENOMEM; start = gen_pool_alloc_algo(muram_pool, size, algo, data); - if (!start) - goto out2; + if (!start) { + kfree(entry); + return -ENOMEM; + } start = start - GENPOOL_OFFSET; memset_io(cpm_muram_addr(start), 0, size); - entry = kmalloc(sizeof(*entry), GFP_ATOMIC); - if (!entry) - goto out1; entry->start = start; entry->size = size; list_add(&entry->head, &muram_block_list); return start; -out1: - gen_pool_free(muram_pool, start, size); -out2: - return -ENOMEM; } /*