Messages in this thread | | | Date | Fri, 21 Jan 2005 19:01:55 +0300 | From | Oleg Nesterov <> | Subject | Re: [PATCH] fix put_user under mmap_sem in sys_get_mempolicy() |
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Andi Kleen wrote: > > I suppose this simpler patch has the same effect (also untested). > > if (flags & ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR)) > return -EINVAL; >@@ -502,6 +502,10 @@ > pol = vma->vm_ops->get_policy(vma, addr); > else > pol = vma->vm_policy; >+ pol2 = mpol_copy(pol); >+ up_read(&mm->mmap_sem); >+ if (IS_ERR(pol2)) >+ return PTR_ERR(pol2); >
I don't think so. With MPOL_F_ADDR|MPOL_F_NODE sys_get_mempolicy calls lookup_node()->get_user_pages() few lines below, so we can't up_read(&mm->mmap_sem) here.
> It's hard to figure out what your patch actually does because > of all the gratious white space changes.
For your convenience here is the code with the patch applied.
if (flags & MPOL_F_ADDR) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma;
err = 0; down_read(&mm->mmap_sem); vma = find_vma_intersection(mm, addr, addr+1); if (!vma) err = -EFAULT; else { if (vma->vm_ops && vma->vm_ops->get_policy) pol = vma->vm_ops->get_policy(vma, addr); else pol = vma->vm_policy;
if (flags & MPOL_F_NODE) { pval = lookup_node(mm, addr); if (pval < 0) err = pval; } } up_read(&mm->mmap_sem); if (err) goto out; } else if (addr) return -EINVAL;
if (!pol) pol = &default_policy;
if (flags & MPOL_F_NODE) { if (!(flags & MPOL_F_ADDR)) { if (pol == current->mempolicy && pol->policy == MPOL_INTERLEAVE) { pval = current->il_next; } else { err = -EINVAL; goto out; } } } else pval = pol->policy; - 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/
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