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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 3 Dec 2019 03:48:16 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xB33mG2Z63569958 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 3 Dec 2019 03:48:16 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EADF852052; Tue, 3 Dec 2019 03:48:15 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 48B5852054; Tue, 3 Dec 2019 03:48:15 +0000 (GMT) Received: from adsilva.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 3C14AA03C6; Tue, 3 Dec 2019 14:48:12 +1100 (AEDT) From: "Alastair D'Silva" To: alastair@d-silva.org Subject: [PATCH v2 01/27] memory_hotplug: Add a bounds check to __add_pages Date: Tue, 3 Dec 2019 14:46:29 +1100 X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191203034655.51561-1-alastair@au1.ibm.com> References: <20191203034655.51561-1-alastair@au1.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19120303-0028-0000-0000-000003C3CC72 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19120303-0029-0000-0000-00002486E431 Message-Id: <20191203034655.51561-2-alastair@au1.ibm.com> Content-Transfer-Encoding: 8bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-02_06:2019-11-29,2019-12-02 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 impostorscore=0 lowpriorityscore=0 mlxscore=0 clxscore=1015 mlxlogscore=999 spamscore=0 phishscore=0 suspectscore=1 adultscore=0 bulkscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912030032 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: Madhavan Srinivasan , David Hildenbrand , Alexey Kardashevskiy , Keith Busch , Masahiro Yamada , Michal Hocko , Paul Mackerras , Mauro Carvalho Chehab , Ira Weiny , Thomas Gleixner , Rob Herring , Dave Jiang , linux-nvdimm@lists.01.org, Vishal Verma , Krzysztof Kozlowski , Anju T Sudhakar , Mahesh Salgaonkar , Andrew Donnellan , Arnd Bergmann , Greg Kurz , Nicholas Piggin , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Dan Williams , Hari Bathini , linux-mm@kvack.org, Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Frederic Barrat , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Alastair D'Silva On PowerPC, the address ranges allocated to OpenCAPI LPC memory are allocated from firmware. These address ranges may be higher than what older kernels permit, as we increased the maximum permissable address in commit 4ffe713b7587 ("powerpc/mm: Increase the max addressable memory to 2PB"). It is possible that the addressable range may change again in the future. In this scenario, we end up with a bogus section returned from __section_nr (see the discussion on the thread "mm: Trigger bug on if a section is not found in __section_nr"). Adding a check here means that we fail early and have an opportunity to handle the error gracefully, rather than rumbling on and potentially accessing an incorrect section. Further discussion is also on the thread ("powerpc: Perform a bounds check in arch_add_memory") http://lkml.kernel.org/r/20190827052047.31547-1-alastair@au1.ibm.com Signed-off-by: Alastair D'Silva Reviewed-by: David Hildenbrand Acked-by: Michal Hocko --- mm/memory_hotplug.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index f307bd82d750..b5be827ecda5 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -278,6 +278,23 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages, return 0; } +static int check_hotplug_memory_addressable(unsigned long pfn, + unsigned long nr_pages) +{ + const u64 max_addr = PFN_PHYS(pfn + nr_pages) - 1; + + if (max_addr >> MAX_PHYSMEM_BITS) { + const u64 max_allowed = (1ull << (MAX_PHYSMEM_BITS + 1)) - 1; + + WARN(1, + "Hotplugged memory exceeds maximum addressable address, range=%#llx-%#llx, maximum=%#llx\n", + PFN_PHYS(pfn), max_addr, max_allowed); + return -E2BIG; + } + + return 0; +} + /* * Reasonably generic function for adding memory. It is * expected that archs that support memory hotplug will @@ -291,6 +308,10 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages, unsigned long nr, start_sec, end_sec; struct vmem_altmap *altmap = restrictions->altmap; + err = check_hotplug_memory_addressable(pfn, nr_pages); + if (err) + return err; + if (altmap) { /* * Validate altmap is within bounds of the total request -- 2.23.0