From patchwork Tue Jul 2 16:38:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11028279 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CD312112C for ; Tue, 2 Jul 2019 16:40:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B813D2862A for ; Tue, 2 Jul 2019 16:40:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AB8C728917; Tue, 2 Jul 2019 16:40:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 463902862A for ; Tue, 2 Jul 2019 16:40:16 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hiLnu-0001iw-0q; Tue, 02 Jul 2019 16:38:50 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hiLnt-0001iQ-4s for xen-devel@lists.xenproject.org; Tue, 02 Jul 2019 16:38:49 +0000 X-Inumbo-ID: dd51bbb4-9ce7-11e9-8f5e-e796baa0a0a8 Received: from esa2.hc3370-68.iphmx.com (unknown [216.71.145.153]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id dd51bbb4-9ce7-11e9-8f5e-e796baa0a0a8; Tue, 02 Jul 2019 16:38:47 +0000 (UTC) Authentication-Results: esa2.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=paul.durrant@citrix.com; spf=Pass smtp.mailfrom=Paul.Durrant@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of paul.durrant@citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="paul.durrant@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa2.hc3370-68.iphmx.com: domain of Paul.Durrant@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="Paul.Durrant@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ~all" Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: v14isdYEz+3Z7zP9Fvqo2WJDcQ4IDsS4awEXOKQkKY8K14Z+Vy61XFAS9EoH89HlGxrAPhy1BV 1/RdCa35yEppB9ED5zTybYqa1YmTRDXqWNiKgnoXxNRh2KaNNypW9itXGcYFq3GFPCDF3WSeMb sy1oxxY4mLDho8JiWpla/EHw3V9oRXQhVFnbOfdy6tTVgVY2yqkGDtmzbsDaZFBixAlw01sx0k WDpFv5G2OxTG4vvktxngAEIhjqGFtM6ONvRinNEN8j9b2nhgKnmb7fF2EuKif5vdEHayB0Xg+/ yB4= X-SBRS: 2.7 X-MesageID: 2501601 X-Ironport-Server: esa2.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.63,443,1557201600"; d="scan'208";a="2501601" From: Paul Durrant To: Date: Tue, 2 Jul 2019 17:38:38 +0100 Message-ID: <20190702163840.2107-2-paul.durrant@citrix.com> X-Mailer: git-send-email 2.20.1.2.gb21ebb671 In-Reply-To: <20190702163840.2107-1-paul.durrant@citrix.com> References: <20190702163840.2107-1-paul.durrant@citrix.com> MIME-Version: 1.0 Subject: [Xen-devel] [PATCH 1/3] xmalloc: stop using a magic '1' in alignment padding X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Julien Grall , Paul Durrant , Jan Beulich Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP Alignment padding inserts a pseudo block header in front of the allocation, sets its size field to the pad size and then ORs in 1, which is equivalent to marking it as a free block, so that xfree() can distinguish it from a real block header. This patch simply replaces the magic '1' with the defined 'FREE_BLOCK' to make it more obvious what's going on. Also, whilst in the neighbourhood, it removes a stray space after a cast. Signed-off-by: Paul Durrant Reviewed-by: Jan Beulich --- Cc: Andrew Cooper Cc: George Dunlap Cc: Ian Jackson Cc: Jan Beulich Cc: Julien Grall Cc: Konrad Rzeszutek Wilk Cc: Stefano Stabellini Cc: Tim Deegan Cc: Wei Liu --- xen/common/xmalloc_tlsf.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/xen/common/xmalloc_tlsf.c b/xen/common/xmalloc_tlsf.c index 2076953ac4..6d889b7bdc 100644 --- a/xen/common/xmalloc_tlsf.c +++ b/xen/common/xmalloc_tlsf.c @@ -595,7 +595,7 @@ void *_xmalloc(unsigned long size, unsigned long align) char *q = (char *)p + pad; struct bhdr *b = (struct bhdr *)(q - BHDR_OVERHEAD); ASSERT(q > (char *)p); - b->size = pad | 1; + b->size = pad | FREE_BLOCK; p = q; } @@ -638,12 +638,12 @@ void xfree(void *p) } /* Strip alignment padding. */ - b = (struct bhdr *)((char *) p - BHDR_OVERHEAD); - if ( b->size & 1 ) + b = (struct bhdr *)((char *)p - BHDR_OVERHEAD); + if ( b->size & FREE_BLOCK ) { p = (char *)p - (b->size & ~1u); b = (struct bhdr *)((char *)p - BHDR_OVERHEAD); - ASSERT(!(b->size & 1)); + ASSERT(!(b->size & FREE_BLOCK)); } xmem_pool_free(p, xenpool); From patchwork Tue Jul 2 16:38:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11028283 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D83DC138B for ; Tue, 2 Jul 2019 16:40:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C50B9284F5 for ; Tue, 2 Jul 2019 16:40:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B97252858E; Tue, 2 Jul 2019 16:40:41 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 516FB284F5 for ; 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client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="paul.durrant@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa2.hc3370-68.iphmx.com: domain of Paul.Durrant@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="Paul.Durrant@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ~all" Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: 1HVVlpBeEyqFY8ue3C4/YfjNRVbEb+HZuPKDv/1luvh/ZkjLiWOFyH5ggji4vddcvDj0msDkW3 7/QbVmFO/gyX6b/o/QkytEcYlSztTizZ4hZHsEC7JY9/cFVNNPhiJ+K9zuJKXL8E2HceVYefgY 9JQu06DMojCgLWNNOVYwfwNnkLa0nrFGWEuztZD50UWoQ+EvmZ9rWFa83pD4kLP7WHRFDYFB7v 2spnYLX9nUL6dmRhP/5a9hcVWrrFWZI/X+RbqZSl6fpISdhgv2SH/9WV1Ph1sj3/QhhorMPN4y NIU= X-SBRS: 2.7 X-MesageID: 2501599 X-Ironport-Server: esa2.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.63,443,1557201600"; d="scan'208";a="2501599" From: Paul Durrant To: Date: Tue, 2 Jul 2019 17:38:39 +0100 Message-ID: <20190702163840.2107-3-paul.durrant@citrix.com> X-Mailer: git-send-email 2.20.1.2.gb21ebb671 In-Reply-To: <20190702163840.2107-1-paul.durrant@citrix.com> References: <20190702163840.2107-1-paul.durrant@citrix.com> MIME-Version: 1.0 Subject: [Xen-devel] [PATCH 2/3] xmalloc: don't evaluate ADD_REGION without holding the pool lock X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Julien Grall , Paul Durrant , Jan Beulich Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP It's not safe to add a region without holding the lock, but this is exactly what may happen if two threads race entering xmem_pool_alloc() before the init_region is set. This patch instead checks for init_region under lock, drops the lock if it needs to allocate a page, takes the lock, adds the region and then confirms init_region is still unset before pointing it at the newly added region. Thus, it is possible that a race may cause an extra region to be added, but there will be no pool metadata corruption. Signed-off-by: Paul Durrant --- Cc: Andrew Cooper Cc: George Dunlap Cc: Ian Jackson Cc: Jan Beulich Cc: Julien Grall Cc: Konrad Rzeszutek Wilk Cc: Stefano Stabellini Cc: Tim Deegan Cc: Wei Liu --- xen/common/xmalloc_tlsf.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/xen/common/xmalloc_tlsf.c b/xen/common/xmalloc_tlsf.c index 6d889b7bdc..71597c3590 100644 --- a/xen/common/xmalloc_tlsf.c +++ b/xen/common/xmalloc_tlsf.c @@ -380,18 +380,22 @@ void *xmem_pool_alloc(unsigned long size, struct xmem_pool *pool) int fl, sl; unsigned long tmp_size; + spin_lock(&pool->lock); if ( pool->init_region == NULL ) { + spin_unlock(&pool->lock); if ( (region = pool->get_mem(pool->init_size)) == NULL ) goto out; + spin_lock(&pool->lock); ADD_REGION(region, pool->init_size, pool); - pool->init_region = region; + /* Re-check since the lock was dropped */ + if ( pool->init_region == NULL ) + pool->init_region = region; } size = (size < MIN_BLOCK_SIZE) ? MIN_BLOCK_SIZE : ROUNDUP_SIZE(size); /* Rounding up the requested size and calculating fl and sl */ - spin_lock(&pool->lock); retry_find: MAPPING_SEARCH(&size, &fl, &sl); From patchwork Tue Jul 2 16:38:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 11028285 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 57EEB112C for ; Tue, 2 Jul 2019 16:40:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 440031FF81 for ; Tue, 2 Jul 2019 16:40:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2F6BC2858A; Tue, 2 Jul 2019 16:40:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id BD2C91FF81 for ; Tue, 2 Jul 2019 16:40:44 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hiLnu-0001j6-BL; Tue, 02 Jul 2019 16:38:50 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hiLnt-0001iR-51 for xen-devel@lists.xenproject.org; Tue, 02 Jul 2019 16:38:49 +0000 X-Inumbo-ID: dd53dc5a-9ce7-11e9-8782-4f699680660f Received: from esa2.hc3370-68.iphmx.com (unknown [216.71.145.153]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id dd53dc5a-9ce7-11e9-8782-4f699680660f; Tue, 02 Jul 2019 16:38:47 +0000 (UTC) Authentication-Results: esa2.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=paul.durrant@citrix.com; spf=Pass smtp.mailfrom=Paul.Durrant@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of paul.durrant@citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="paul.durrant@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa2.hc3370-68.iphmx.com: domain of Paul.Durrant@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="Paul.Durrant@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ~all" Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="Paul.Durrant@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: P8DlWrgjUXbq7h/Aj4uxKaFCre30NiQS6MFXQte0CQZqPBpzhWoZlO0JVidhnti2AJ1dYmeBAO YgJp75ZLQL5bmOzY1A+Jd1XnD6PztcVEleS4EEdGNF0IgRP2gjx9pcy/U2fm6lpA7A81QRsRgw g4kH5vA3j4jJWjmkyX+fqJ+3tP54rxR5orEJZchqfJXhybqxpvFfNESmLSfniIRw7U4xZ+I2Gy ZX22nkQz5CLqmiAc0dBWlHzDp5pxNnvlQSES3FDw/758w1kpsXL5QgQXAHZtFtf/kQh6vEvL0R JZU= X-SBRS: 2.7 X-MesageID: 2501602 X-Ironport-Server: esa2.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.63,443,1557201600"; d="scan'208";a="2501602" From: Paul Durrant To: Date: Tue, 2 Jul 2019 17:38:40 +0100 Message-ID: <20190702163840.2107-4-paul.durrant@citrix.com> X-Mailer: git-send-email 2.20.1.2.gb21ebb671 In-Reply-To: <20190702163840.2107-1-paul.durrant@citrix.com> References: <20190702163840.2107-1-paul.durrant@citrix.com> MIME-Version: 1.0 Subject: [Xen-devel] [PATCH 3/3] xmalloc: add a Kconfig option to poison free pool memory X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Julien Grall , Paul Durrant , Jan Beulich Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP This patch adds POOL_POISON to the Kconfig DEBUG options. If set, free blocks (greater than MIN_BLOCK_SIZE) will be poisoned with 0xAA bytes which will then be verified when memory is subsequently allocated. This can help in spotting heap corruption, particularly use-after-free. Signed-off-by: Paul Durrant --- Cc: Andrew Cooper Cc: George Dunlap Cc: Ian Jackson Cc: Jan Beulich Cc: Julien Grall Cc: Konrad Rzeszutek Wilk Cc: Stefano Stabellini Cc: Tim Deegan Cc: Wei Liu --- xen/Kconfig.debug | 7 +++++++ xen/common/xmalloc_tlsf.c | 13 +++++++++++++ 2 files changed, 20 insertions(+) diff --git a/xen/Kconfig.debug b/xen/Kconfig.debug index daacf85141..4f18a1144e 100644 --- a/xen/Kconfig.debug +++ b/xen/Kconfig.debug @@ -105,6 +105,13 @@ config DEBUG_TRACE either directly to the console or are printed to console in case of a system crash. +config POOL_POISON + bool "Poison free xenpool blocks" + default DEBUG + ---help--- + Poison free blocks with 0xAA bytes and verify them when a block is + allocated in order to spot use-after-free issues. + endif # DEBUG || EXPERT endmenu diff --git a/xen/common/xmalloc_tlsf.c b/xen/common/xmalloc_tlsf.c index 71597c3590..a12dbc8e11 100644 --- a/xen/common/xmalloc_tlsf.c +++ b/xen/common/xmalloc_tlsf.c @@ -223,6 +223,10 @@ static inline void EXTRACT_BLOCK_HDR(struct bhdr *b, struct xmem_pool *p, int fl static inline void EXTRACT_BLOCK(struct bhdr *b, struct xmem_pool *p, int fl, int sl) { +#ifdef CONFIG_POOL_POISON + unsigned int i; +#endif /* CONFIG_POOL_POISON */ + if ( b->ptr.free_ptr.next ) b->ptr.free_ptr.next->ptr.free_ptr.prev = b->ptr.free_ptr.prev; @@ -240,6 +244,10 @@ static inline void EXTRACT_BLOCK(struct bhdr *b, struct xmem_pool *p, int fl, } } b->ptr.free_ptr = (struct free_ptr) {NULL, NULL}; +#ifdef CONFIG_POOL_POISON + for ( i = MIN_BLOCK_SIZE; i < (b->size & BLOCK_SIZE_MASK); i++ ) + ASSERT(b->ptr.buffer[i] == 0xAA); +#endif /* CONFIG_POOL_POISON */ } /** @@ -247,6 +255,11 @@ static inline void EXTRACT_BLOCK(struct bhdr *b, struct xmem_pool *p, int fl, */ static inline void INSERT_BLOCK(struct bhdr *b, struct xmem_pool *p, int fl, int sl) { +#ifdef CONFIG_POOL_POISON + if ( (b->size & BLOCK_SIZE_MASK) > MIN_BLOCK_SIZE ) + memset(b->ptr.buffer + MIN_BLOCK_SIZE, 0xAA, + (b->size & BLOCK_SIZE_MASK) - MIN_BLOCK_SIZE); +#endif /* CONFIG_POOL_POISON */ b->ptr.free_ptr = (struct free_ptr) {NULL, p->matrix[fl][sl]}; if ( p->matrix[fl][sl] ) p->matrix[fl][sl]->ptr.free_ptr.prev = b;