From patchwork Tue Nov 6 22:38:15 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [03/16] mm: check rb_subtree_gap correctness Date: Tue, 06 Nov 2012 12:38:15 -0000 From: Andrew Morton X-Patchwork-Id: 197571 Message-Id: <20121106143815.2d311383.akpm@linux-foundation.org> To: Michel Lespinasse Cc: Rik van Riel , Hugh Dickins , linux-kernel@vger.kernel.org, Russell King , Ralf Baechle , Paul Mundt , "David S. Miller" , Chris Metcalf , x86@kernel.org, William Irwin , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.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! --- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- 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