Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754371AbbH0OoJ (ORCPT ); Thu, 27 Aug 2015 10:44:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:27155 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754187AbbH0OoB (ORCPT ); Thu, 27 Aug 2015 10:44:01 -0400 From: Jan Stancek To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org Cc: jstancek@redhat.com Subject: [PATCH 2/2] drivers/base/node.c: skip non-present sections in register_mem_sect_under_node Date: Thu, 27 Aug 2015 16:43:50 +0200 Message-Id: In-Reply-To: <1a7c81db42986a6fa27260fe189890bffc8a9cce.1440665740.git.jstancek@redhat.com> References: <1a7c81db42986a6fa27260fe189890bffc8a9cce.1440665740.git.jstancek@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3057 Lines: 72 Skip non-present sections in mem_blk to avoid crashing during boot at register_mem_sect_under_node()->get_nid_for_pfn(): Unable to handle kernel paging request for data at address 0xf000000000080020 Faulting instruction address: 0xc00000000866b480 Oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 14 PID: 1 Comm: swapper/14 Not tainted 4.2.0-rc8+ #6 task: c00000001e480000 ti: c00000001e500000 task.ti: c00000001e500000 NIP: c00000000866b480 LR: c00000000851aecc CTR: 0000000000000400 ... NIP [c00000000866b480] get_nid_for_pfn+0x10/0x30 LR [c00000000851aecc] register_mem_sect_under_node+0x9c/0x190 Call Trace: [c00000001e503b10] [c0000000084f89a4] put_device+0x24/0x40 (unreliable) [c00000001e503b60] [c00000000851b3d4] register_one_node+0x2b4/0x390 [c00000001e503bc0] [c000000008ae7a50] topology_init+0x4c/0x1e8 [c00000001e503c30] [c00000000800b3bc] do_one_initcall+0x10c/0x260 [c00000001e503d00] [c000000008ae41b4] kernel_init_freeable+0x27c/0x364 [c00000001e503dc0] [c00000000800bc14] kernel_init+0x24/0x130 [c00000001e503e30] [c000000008009530] ret_from_kernel_thread+0x5c/0xac Instruction dump: 4e800020 60000000 60000000 60420000 3b80ffed 4bffffc8 00000000 00000000 3920ffff 78633664 792900c4 7d434a14 2faa0000 41de0010 7c63482a ---[ end trace e9ab4a173e0cee14 ]--- This has been observed during kdump kernel boot on ppc64le KVM guest (page size: 65536, sections_per_block: 16, PAGES_PER_SECTION: 256) where kdump adds "rtas" to list of usable regions: # hexdump -C /sys/firmware/devicetree/base/rtas/linux,rtas-base 00000000 2f ff 00 00 |/...| [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000000000000-0x000000001fffffff] [ 0.000000] node 0: [mem 0x000000002fff0000-0x000000002fffffff] Crash happens when register_mem_sect_under_node goes over mem_blk that spans sections 32-47, 32-46 are not present, 47 is present: 32 * 256 * 65536 == 0x20000000 47 * 256 * 65536 == 0x2f000000 It tries to access page for first pfn of this mem_blk (8192 == 32 * 256) and crashes. Signed-off-by: Jan Stancek Cc: Greg Kroah-Hartman --- drivers/base/node.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/base/node.c b/drivers/base/node.c index 4c7423a4b5f4..e638cfde7486 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -390,6 +390,9 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid) sect_no <= mem_blk->end_section_nr; sect_no++) { + if (!present_section_nr(sect_no)) + continue; + sect_start_pfn = section_nr_to_pfn(sect_no); sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1; -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/