From patchwork Tue Nov 6 22:38:15 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 1707311 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 969BD3FCAE for ; Tue, 6 Nov 2012 22:40:46 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TVrmo-0006Fy-Ar; Tue, 06 Nov 2012 22:38:22 +0000 Received: from mail.linuxfoundation.org ([140.211.169.12]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TVrmk-0006Ff-40 for linux-arm-kernel@lists.infradead.org; Tue, 06 Nov 2012 22:38:18 +0000 Received: from akpm.mtv.corp.google.com (216-239-45-4.google.com [216.239.45.4]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id D6AD326; Tue, 6 Nov 2012 22:38:15 +0000 (UTC) Date: Tue, 6 Nov 2012 14:38:15 -0800 From: Andrew Morton To: Michel Lespinasse Subject: Re: [PATCH 03/16] mm: check rb_subtree_gap correctness Message-Id: <20121106143815.2d311383.akpm@linux-foundation.org> In-Reply-To: <1352155633-8648-4-git-send-email-walken@google.com> References: <1352155633-8648-1-git-send-email-walken@google.com> <1352155633-8648-4-git-send-email-walken@google.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20121106_173818_554160_BBEFF603 X-CRM114-Status: GOOD ( 15.62 ) X-Spam-Score: 1.1 (+) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (1.1 points) pts rule name description ---- ---------------------- -------------------------------------------------- 3.0 KHOP_BIG_TO_CC Sent to 10+ recipients instaed of Bcc or a list -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: linux-mips@linux-mips.org, Rik van Riel , Russell King , William Irwin , linux-sh@vger.kernel.org, x86@kernel.org, Hugh Dickins , linux-kernel@vger.kernel.org, Ralf Baechle , linux-mm@kvack.org, Paul Mundt , Chris Metcalf , sparclinux@vger.kernel.org, "David S. Miller" , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org On Mon, 5 Nov 2012 14:47:00 -0800 Michel Lespinasse wrote: > When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is > correctly set for every vma and that mm->highest_vm_end is also correct. > > Also add an explicit 'bug' variable to track if browse_rb() detected any > invalid condition. > > ... > > @@ -365,7 +365,7 @@ static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root) > #ifdef CONFIG_DEBUG_VM_RB > static int browse_rb(struct rb_root *root) > { > - int i = 0, j; > + int i = 0, j, bug = 0; > struct rb_node *nd, *pn = NULL; > unsigned long prev = 0, pend = 0; > > @@ -373,29 +373,33 @@ static int browse_rb(struct rb_root *root) > struct vm_area_struct *vma; > vma = rb_entry(nd, struct vm_area_struct, vm_rb); > if (vma->vm_start < prev) > - printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; > + printk("vm_start %lx prev %lx\n", vma->vm_start, prev), bug = 1; > if (vma->vm_start < pend) > - printk("vm_start %lx pend %lx\n", vma->vm_start, pend); > + printk("vm_start %lx pend %lx\n", vma->vm_start, pend), bug = 1; > if (vma->vm_start > vma->vm_end) > - printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); > + printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start), bug = 1; > + if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) > + printk("free gap %lx, correct %lx\n", > + vma->rb_subtree_gap, > + vma_compute_subtree_gap(vma)), bug = 1; OK, now who did that. Whoever it was: stop it or you'll have your kernel license revoked! --- a/mm/mmap.c~mm-check-rb_subtree_gap-correctness-fix +++ a/mm/mmap.c @@ -372,16 +372,25 @@ static int browse_rb(struct rb_root *roo for (nd = rb_first(root); nd; nd = rb_next(nd)) { struct vm_area_struct *vma; vma = rb_entry(nd, struct vm_area_struct, vm_rb); - if (vma->vm_start < prev) - printk("vm_start %lx prev %lx\n", vma->vm_start, prev), bug = 1; - if (vma->vm_start < pend) - printk("vm_start %lx pend %lx\n", vma->vm_start, pend), bug = 1; - if (vma->vm_start > vma->vm_end) - printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start), bug = 1; - if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) + if (vma->vm_start < prev) { + printk("vm_start %lx prev %lx\n", vma->vm_start, prev); + bug = 1; + } + if (vma->vm_start < pend) { + printk("vm_start %lx pend %lx\n", vma->vm_start, pend); + bug = 1; + } + if (vma->vm_start > vma->vm_end) { + printk("vm_end %lx < vm_start %lx\n", + vma->vm_end, vma->vm_start); + bug = 1; + } + if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { printk("free gap %lx, correct %lx\n", vma->rb_subtree_gap, - vma_compute_subtree_gap(vma)), bug = 1; + vma_compute_subtree_gap(vma)); + bug = 1; + } i++; pn = nd; prev = vma->vm_start; @@ -390,8 +399,10 @@ static int browse_rb(struct rb_root *roo j = 0; for (nd = pn; nd; nd = rb_prev(nd)) j++; - if (i != j) - printk("backwards %d, forwards %d\n", j, i), bug = 1; + if (i != j) { + printk("backwards %d, forwards %d\n", j, i); + bug = 1; + } return bug ? -1 : i; } @@ -411,14 +422,20 @@ void validate_mm(struct mm_struct *mm) vma = vma->vm_next; i++; } - if (i != mm->map_count) - printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; - if (highest_address != mm->highest_vm_end) + if (i != mm->map_count) { + printk("map_count %d vm_next %d\n", mm->map_count, i); + bug = 1; + } + if (highest_address != mm->highest_vm_end) { printk("mm->highest_vm_end %lx, found %lx\n", - mm->highest_vm_end, highest_address), bug = 1; + mm->highest_vm_end, highest_address); + bug = 1; + } i = browse_rb(&mm->mm_rb); - if (i != mm->map_count) - printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; + if (i != mm->map_count) { + printk("map_count %d rb %d\n", mm->map_count, i); + bug = 1; + } BUG_ON(bug); } #else