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 168DD156C6A for ; Sun, 14 Sep 2025 00:35:58 +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=1757810158; cv=none; b=fh6Gu7sBvsIPpRgJqpkJlWvM3IWSGWHjpD/INhtDDy2nNvBb9vYaOeIHklxWn67zif46YlW3xmfw8O2LMivqMvEqYOvOs9mYw6oxei1af241pQbFnhSu13hn31LM562yizHrPMCfM5EP6tW3Ohtfs8wEh3MQwE2kvSXxBsWgOHE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757810158; c=relaxed/simple; bh=1h1QkgPAN7dN8254DcsYXY8VFV/f1NE4RSrIE0buGCU=; h=Date:To:From:Subject:Message-Id; b=K0dBjMjdbcWxjsH/61pc3vCCJ2ehzSLG3J5LRVHeFoFY25vp08ucrstMmfykLrgw74d1mgRv2qtj2KkFD2xVAtjAtCMvU0LBGD5KoegEfz6oI5uSqkUOcNXRx+9/mv8jpQb/Yrftutsm+AZRyXsoR5Bo7B9eoAId2ty63Lr3ixA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=HuKastWR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="HuKastWR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0F7EC4CEEB; Sun, 14 Sep 2025 00:35:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1757810158; bh=1h1QkgPAN7dN8254DcsYXY8VFV/f1NE4RSrIE0buGCU=; h=Date:To:From:Subject:From; b=HuKastWRicqAw41Z4bvLAhxq8AUWLf1Beak2yxrvgSSgv9SGow10Vh93TgT1YPyYl eads/09X7yF/pNmC8qkfE2opqT1AH1lE1V3k/upEQJE44WKEcXf6VQvVs4tkh5LE13 jHwdjrgYs9uROJVysySC9ho30Db9NTcLhPk20qoo= Date: Sat, 13 Sep 2025 17:35:57 -0700 To: mm-commits@vger.kernel.org,vgoyal@redhat.com,tglx@linutronix.de,mingo@redhat.com,hpa@zytor.com,dyoung@redhat.com,coxu@redhat.com,bp@alien8.de,bhe@redhat.com,fuqiang.wang@easystack.cn,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-nonmm-stable] x86-kexec-fix-potential-cmem-ranges-out-of-memory.patch removed from -mm tree Message-Id: <20250914003557.E0F7EC4CEEB@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: x86/kexec: fix potential cmem->ranges out of memory has been removed from the -mm tree. Its filename was x86-kexec-fix-potential-cmem-ranges-out-of-memory.patch This patch was dropped because it was merged into the mm-nonmm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: fuqiang wang Subject: x86/kexec: fix potential cmem->ranges out of memory Date: Thu, 4 Sep 2025 17:38:52 +0800 In memmap_exclude_ranges(), elfheader will be excluded from crashk_res. In the current x86 architecture code, the elfheader is always allocated at crashk_res.start. It seems that there won't be a new split range. But it depends on the allocation position of elfheader in crashk_res. To avoid potential out of memory in future, add a extra slot. Otherwise loading the kdump kernel will fail because crash_exclude_mem_range will return -ENOMEM. random kexec_buf for passing dm crypt keys may cause a range split too, add another extra slot here. The similar issue also exists in fill_up_crash_elf_data(). The range to be excluded is [0, 1M], start (0) is special and will not appear in the middle of existing cmem->ranges[]. But in cast the low 1M could be changed in the future, add a extra slot too. Previous discussions: [1] https://lore.kernel.org/kexec/ZXk2oBf%2FT1Ul6o0c@MiWiFi-R3L-srv/ [2] https://lore.kernel.org/kexec/273284e8-7680-4f5f-8065-c5d780987e59@easystack.cn/ [3] https://lore.kernel.org/kexec/ZYQ6O%2F57sHAPxTHm@MiWiFi-R3L-srv/ Link: https://lkml.kernel.org/r/20250904093855.1180154-1-coxu@redhat.com Signed-off-by: fuqiang wang Signed-off-by: Baoquan He Signed-off-by: Coiby Xu Cc: Dave Young Cc: Vivek Goyal Cc: Borislav Betkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Thomas Gleinxer Signed-off-by: Andrew Morton --- arch/x86/kernel/crash.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) --- a/arch/x86/kernel/crash.c~x86-kexec-fix-potential-cmem-ranges-out-of-memory +++ a/arch/x86/kernel/crash.c @@ -165,8 +165,18 @@ static struct crash_mem *fill_up_crash_e /* * Exclusion of crash region, crashk_low_res and/or crashk_cma_ranges * may cause range splits. So add extra slots here. + * + * Exclusion of low 1M may not cause another range split, because the + * range of exclude is [0, 1M] and the condition for splitting a new + * region is that the start, end parameters are both in a certain + * existing region in cmem and cannot be equal to existing region's + * start or end. Obviously, the start of [0, 1M] cannot meet this + * condition. + * + * But in order to lest the low 1M could be changed in the future, + * (e.g. [start, 1M]), add a extra slot. */ - nr_ranges += 2 + crashk_cma_cnt; + nr_ranges += 3 + crashk_cma_cnt; cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); if (!cmem) return NULL; @@ -322,10 +332,15 @@ int crash_setup_memmap_entries(struct ki struct crash_mem *cmem; /* - * Using random kexec_buf for passing dm crypt keys may cause a range - * split. So use two slots here. + * In the current x86 architecture code, the elfheader is always + * allocated at crashk_res.start. But it depends on the allocation + * position of elfheader in crashk_res. To avoid potential out of + * bounds in future, add an extra slot. + * + * And using random kexec_buf for passing dm crypt keys may cause a + * range split too, add another extra slot here. */ - nr_ranges = 2; + nr_ranges = 3; cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); if (!cmem) return -ENOMEM; _ Patches currently in -mm which might be from fuqiang.wang@easystack.cn are