From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 309DAEB64D7 for ; Tue, 20 Jun 2023 23:57:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229867AbjFTX5j (ORCPT ); Tue, 20 Jun 2023 19:57:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229759AbjFTX5g (ORCPT ); Tue, 20 Jun 2023 19:57:36 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0DDF819F for ; Tue, 20 Jun 2023 16:57:35 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-bf34588085bso3242704276.0 for ; Tue, 20 Jun 2023 16:57:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1687305454; x=1689897454; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=BGbrY/f1fvBNW9z8go6Nnz06u29111qaAGQndqYmZbI=; b=P9ZGKNT+TEzfnNjgXfWsFMxrjrmo19InxA9Ltzw94eBOzcf0DrJjIadY39g5B1ARES UM8Tb66YAZoM1qvWyjNLmdfb7GBwdGln7qA5RgXbZWXGaZHvI0XHaH/HBL1QpJNOQgUm 6OloW5Gfvh2xzMIEA3ALlJsZDF0ta5gG6htWRcVitzaGC/HTclOzVZESltb69EPM+Vbp ulOrRqMr+3gQkWyLLTEaVyZRb1j645qYTNnqpW50MZl/4SibKrzjz7laJRB/LZnjYsyE XMOaY7sjsOrxZl8Y6VKGCVQZWc8BmHDWraN0TJszAdVqPx1QEoL6EPZTqJhDF1Ftewq7 eOYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687305454; x=1689897454; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=BGbrY/f1fvBNW9z8go6Nnz06u29111qaAGQndqYmZbI=; b=IwOWlrT8F0vRn91nCBV0pb8nDFj7HfW3lUTIoN+Qc9c8g70aN19WpVI/Uuv/wVU0Dn igbSYKOdwDfxywZkAkvTxID9pcXAN1ZbCHZjKq3F+DcwZzD4UOZSyl00tWk8td8+je3W MRTXleCE0GVrYNbpFw0ReCPsVVzpEQJbdcSMmU1zU2V6sjw1XR3qSN/KzqG32EnrC1E+ aQHCyaqNoiI5tHOt7ft4QnfY3k0b21qVId+osLg7MA1PzotyMvFOnisoecDv3vOmdtVQ m9MK686vjDFE1mM6PHj1kw3NDegvJRrMgw43/JbhrHe63zusYMSzm7KA0oShbydpe6Y9 z6KQ== X-Gm-Message-State: AC+VfDxDaD6KJODSd+koF4j7p71HKxSB+gKkBSarZIyICUGE4RnmRK9m sAIHmEAH05yoUL5qh6WTmnDo++T0HZM= X-Google-Smtp-Source: ACHHUZ6kw7oTpcpzUTFKAorHv5DtOn6LBqwlXR1p5RtO+KTrOjHZ+LXWbslSzGMAafSpF8zUkeChCRjPRTw= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:201:3f57:9854:e19:8906]) (user=surenb job=sendgmr) by 2002:a5b:bc9:0:b0:bad:41b:f343 with SMTP id c9-20020a5b0bc9000000b00bad041bf343mr5127082ybr.1.1687305454340; Tue, 20 Jun 2023 16:57:34 -0700 (PDT) Date: Tue, 20 Jun 2023 16:57:26 -0700 In-Reply-To: <20230620235726.3873043-1-surenb@google.com> Mime-Version: 1.0 References: <20230620235726.3873043-1-surenb@google.com> X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog Message-ID: <20230620235726.3873043-3-surenb@google.com> Subject: [PATCH 3/3] mm: check for VMA being detached before destroying it From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: willy@infradead.org, torvalds@linuxfoundation.org, vegard.nossum@oracle.com, mpe@ellerman.id.au, Liam.Howlett@oracle.com, lrh2000@pku.edu.cn, mgorman@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org By the time VMA is freed it has to be detached with the exception of exit_mmap which is destroying the whole VMA tree. Enforce this requirement before freeing the VMA. exit_mmap in the only user calling __vm_area_free directly, therefore it won't trigger the new check. Change VMA initialization to mark new VMAs as detached and change that flag once the VMA is added into a tree. Suggested-by: Linus Torvalds Signed-off-by: Suren Baghdasaryan --- include/linux/mm.h | 4 ++-- kernel/fork.c | 2 ++ mm/internal.h | 1 + 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 74e3033c9fc2..9a10fcdb134e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -247,7 +247,7 @@ void setup_initial_init_mm(void *start_code, void *end_code, struct vm_area_struct *vm_area_alloc(struct mm_struct *); struct vm_area_struct *vm_area_dup(struct vm_area_struct *); void vm_area_free(struct vm_area_struct *); -/* Use only if VMA has no other users */ +/* Use only if VMA has no other users and might still be attached to a tree */ void __vm_area_free(struct vm_area_struct *vma); #ifndef CONFIG_MMU @@ -751,7 +751,7 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) vma->vm_mm = mm; vma->vm_ops = &dummy_vm_ops; INIT_LIST_HEAD(&vma->anon_vma_chain); - vma_mark_detached(vma, false); + vma->detached = true; vma_numab_state_init(vma); } diff --git a/kernel/fork.c b/kernel/fork.c index 41c964104b58..000fc429345c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -540,6 +540,7 @@ static void vm_area_free_rcu_cb(struct rcu_head *head) /* The vma should not be locked while being destroyed. */ VM_BUG_ON_VMA(rwsem_is_locked(&vma->vm_lock->lock), vma); + WARN_ON_ONCE(!vma->detached); __vm_area_free(vma); } #endif @@ -549,6 +550,7 @@ void vm_area_free(struct vm_area_struct *vma) #ifdef CONFIG_PER_VMA_LOCK call_rcu(&vma->vm_rcu, vm_area_free_rcu_cb); #else + WARN_ON_ONCE(!vma->detached); __vm_area_free(vma); #endif } diff --git a/mm/internal.h b/mm/internal.h index 68410c6d97ac..728189e6c703 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1068,6 +1068,7 @@ static inline void vma_iter_store(struct vma_iterator *vmi, vmi->mas.index = vma->vm_start; vmi->mas.last = vma->vm_end - 1; mas_store_prealloc(&vmi->mas, vma); + vma_mark_detached(vma, false); } static inline int vma_iter_store_gfp(struct vma_iterator *vmi, -- 2.41.0.162.gfafddb0af9-goog