From patchwork Tue Aug 16 09:46:38 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 9283107 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3E0E560839 for ; Tue, 16 Aug 2016 09:47:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2DBA1285C4 for ; Tue, 16 Aug 2016 09:47:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 21FD2285C6; Tue, 16 Aug 2016 09:47:04 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 52E6E285C4 for ; Tue, 16 Aug 2016 09:47:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753133AbcHPJrB (ORCPT ); Tue, 16 Aug 2016 05:47:01 -0400 Received: from foss.arm.com ([217.140.101.70]:45689 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751950AbcHPJq5 (ORCPT ); Tue, 16 Aug 2016 05:46:57 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 13F21318; Tue, 16 Aug 2016 02:48:29 -0700 (PDT) Received: from melchizedek.cambridge.arm.com (melchizedek.cambridge.arm.com [10.1.206.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 465FA3F32C; Tue, 16 Aug 2016 02:46:55 -0700 (PDT) From: James Morse To: linux-pm@vger.kernel.org Cc: "Rafael J . Wysocki" , Len Brown , Pavel Machek , James Morse , Joerg Roedel Subject: [PATCH] PM / hibernate: Fix rtree_next_node() not to walk off the end of the node/zone lists Date: Tue, 16 Aug 2016 10:46:38 +0100 Message-Id: <1471340798-27968-1-git-send-email-james.morse@arm.com> X-Mailer: git-send-email 2.8.0.rc3 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP rtree_next_node() walks the linked list of leaf nodes to find the next block of pages in the struct memory_bitmap. If it walks off the end of the list of nodes, it walks the list of memory zones to find the next region of memory. If it walks off the end of the list of zones, it returns false. This leaves the struct bm_position's node and zone pointers pointing at their respective struct list_heads in struct mem_zone_bm_rtree. memory_bm_find_bit() uses struct bm_position's node and zone pointers to avoid walking lists and trees if the next bit appears in the same node/zone. It handles these values being stale. Swap rtree_next_node()s 'step then test' to 'test-next then step', this means if we reach the end of memory we return false and leave the node and zone pointers as they were. This fixes a panic on resume using AMD Seattle with 64K pages: [ 6.868732] Freezing user space processes ... (elapsed 0.000 seconds) done. [ 6.875753] Double checking all user space processes after OOM killer disable... (elapsed 0.000 seconds) [ 6.896453] PM: Using 3 thread(s) for decompression. [ 6.896453] PM: Loading and decompressing image data (5339 pages)... [ 7.318890] PM: Image loading progress: 0% [ 7.323395] Unable to handle kernel paging request at virtual address 00800040 [ 7.330611] pgd = ffff000008df0000 [ 7.334003] [00800040] *pgd=00000083fffe0003, *pud=00000083fffe0003, *pmd=00000083fffd0003, *pte=0000000000000000 [ 7.344266] Internal error: Oops: 96000005 [#1] PREEMPT SMP [ 7.349825] Modules linked in: [ 7.352871] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G W I 4.8.0-rc1 #4737 [ 7.360512] Hardware name: AMD Overdrive/Supercharger/Default string, BIOS ROD1002C 04/08/2016 [ 7.369109] task: ffff8003c0220000 task.stack: ffff8003c0280000 [ 7.375020] PC is at set_bit+0x18/0x30 [ 7.378758] LR is at memory_bm_set_bit+0x24/0x30 [ 7.383362] pc : [] lr : [] pstate: 60000045 [ 7.390743] sp : ffff8003c0283b00 [ 7.473551] [ 7.475031] Process swapper/0 (pid: 1, stack limit = 0xffff8003c0280020) [ 7.481718] Stack: (0xffff8003c0283b00 to 0xffff8003c0284000) [ 7.800075] Call trace: [ 7.887097] [] set_bit+0x18/0x30 [ 7.891876] [] duplicate_memory_bitmap.constprop.38+0x54/0x70 [ 7.899172] [] snapshot_write_next+0x22c/0x47c [ 7.905166] [] load_image_lzo+0x754/0xa88 [ 7.910725] [] swsusp_read+0x144/0x230 [ 7.916025] [] load_image_and_restore+0x58/0x90 [ 7.922105] [] software_resume+0x2f0/0x338 [ 7.927752] [] do_one_initcall+0x38/0x11c [ 7.933314] [] kernel_init_freeable+0x14c/0x1ec [ 7.939395] [] kernel_init+0x10/0xfc [ 7.944520] [] ret_from_fork+0x10/0x40 [ 7.949820] Code: d2800022 8b400c21 f9800031 9ac32043 (c85f7c22) [ 7.955909] ---[ end trace 0024a5986e6ff323 ]--- [ 7.960529] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Here struct mem_zone_bm_rtree's start_pfn has been returned instead of struct rtree_node's addr as the node/zone pointers are corrupt after we walked off the end of the lists during mark_unsafe_pages(). This behaviour was exposed by 6dbecfd345a6 ("PM / hibernate: Simplify mark_unsafe_pages()"), which caused mark_unsafe_pages() to call duplicate_memory_bitmap(), which uses memory_bm_find_bit() after walking off the end of the memory bitmap. Fixes: 3a20cb177961 ("PM / Hibernate: Implement position keeping in radix tree") Signed-off-by: James Morse Cc: Joerg Roedel --- kernel/power/snapshot.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 9a0178c2ac1d..b02228411d57 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -835,9 +835,9 @@ static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn) */ static bool rtree_next_node(struct memory_bitmap *bm) { - bm->cur.node = list_entry(bm->cur.node->list.next, - struct rtree_node, list); - if (&bm->cur.node->list != &bm->cur.zone->leaves) { + if (!list_is_last(&bm->cur.node->list, &bm->cur.zone->leaves)) { + bm->cur.node = list_entry(bm->cur.node->list.next, + struct rtree_node, list); bm->cur.node_pfn += BM_BITS_PER_BLOCK; bm->cur.node_bit = 0; touch_softlockup_watchdog(); @@ -845,9 +845,9 @@ static bool rtree_next_node(struct memory_bitmap *bm) } /* No more nodes, goto next zone */ - bm->cur.zone = list_entry(bm->cur.zone->list.next, + if (!list_is_last(&bm->cur.zone->list, &bm->zones)) { + bm->cur.zone = list_entry(bm->cur.zone->list.next, struct mem_zone_bm_rtree, list); - if (&bm->cur.zone->list != &bm->zones) { bm->cur.node = list_entry(bm->cur.zone->leaves.next, struct rtree_node, list); bm->cur.node_pfn = 0;