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 BDC11C7619A for ; Wed, 12 Apr 2023 14:53:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229861AbjDLOxP (ORCPT ); Wed, 12 Apr 2023 10:53:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229626AbjDLOxN (ORCPT ); Wed, 12 Apr 2023 10:53:13 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BD543A90 for ; Wed, 12 Apr 2023 07:53:05 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id o19-20020a254113000000b00b8ed021361bso12702719yba.7 for ; Wed, 12 Apr 2023 07:53:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1681311184; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=CwA0wdGrULC2XXBzkQfVWleO9hyls9jS7CAlyZ8lvMo=; b=BGJ19UUT/KQmXwBdHwvfufxanTrfOtkalEb3y2N+im3F2wdY+eRyJvh/ocOo8nqvpt uIcfLl18+AYnrHG4kmP2Uz8d6wIAZ9dx8yRd9Umw2JeCcoKxqj5pmjixgiZHtkC2BrgW oSHxZTZMW29EHRY01yVSztq5fRm8X1vjMchRqarRQjuPc/GNpryrcg5n7M2vJzY9DhIQ +w2LOGFSsfRD4VqKwBlOEX8NzX+CuE3pYgcQxQOePaJ2fG446CSGdzQ2QUOhRZ6jjgRB 5pEb2j+e+90dkmujhtCU8zi9mrzviRnvG+dSdZyM1nUjKupT6dPf7tEIjh3t5Qb4NvIu s4SA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1681311184; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=CwA0wdGrULC2XXBzkQfVWleO9hyls9jS7CAlyZ8lvMo=; b=6ShHYmWmOJZfT+H4I2mueY5npBG84DwEMMUvefgPk6fRKnzXkxzWAMMOTE/a1wk9zw h9DO+EZDK+vbT8G8SeBHgCeuX31PeV/w7Y95NLOsYl6yvV3rz3Dot/jAw2u/VUqnfL2a Hzg1W+sZjNEiHpOxwMX+pW2xiVZ+faX3w0ZUsPt7okAJ3YbALvMh/JTSUQXloXGt3wd1 R2ANpDdSRKghIWM12nC7ym0CcHBtMvtk+uAMQBl3KLi0mRMeixErkrxn27aHZ+iBF0l2 nzHEe8zp5u4GFyvuWXL/n+9YBwgdKriVAZC/yIfNtzN6qmdmYN5UVykcdQDKeU6eD8Qr AWEA== X-Gm-Message-State: AAQBX9cEMFDdi7VnBgIXWhu+T9tOQZmg/Tp4ZYmNX3Yk84n1gAiKdtf7 5iGOWrs8ztItf/eSb/cj8hnudUPYh8I= X-Google-Smtp-Source: AKy350Y9H8x8fkMOv72KbbGnFPvZ5mHfzvPfBgJCLqdyjWcNAGuZGxLlLfr/LwfWgzBFvM7gkBOLd4qRA1E= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:901c:7904:40a1:1b6c]) (user=glider job=sendgmr) by 2002:a25:c905:0:b0:b77:81f:42dc with SMTP id z5-20020a25c905000000b00b77081f42dcmr12063363ybf.1.1681311184657; Wed, 12 Apr 2023 07:53:04 -0700 (PDT) Date: Wed, 12 Apr 2023 16:52:59 +0200 Mime-Version: 1.0 X-Mailer: git-send-email 2.40.0.577.gac1e443424-goog Message-ID: <20230412145300.3651840-1-glider@google.com> Subject: [PATCH 1/2] mm: kmsan: handle alloc failures in kmsan_vmap_pages_range_noflush() From: Alexander Potapenko To: glider@google.com Cc: urezki@gmail.com, hch@infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, elver@google.com, dvyukov@google.com, kasan-dev@googlegroups.com, Dipanjan Das Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As reported by Dipanjan Das, when KMSAN is used together with kernel fault injection (or, generally, even without the latter), calls to kcalloc() or __vmap_pages_range_noflush() may fail, leaving the metadata mappings for the virtual mapping in an inconsistent state. When these metadata mappings are accessed later, the kernel crashes. To address the problem, we return a non-zero error code from kmsan_vmap_pages_range_noflush() in the case of any allocation/mapping failure inside it, and make vmap_pages_range_noflush() return an error if KMSAN fails to allocate the metadata. This patch also removes KMSAN_WARN_ON() from vmap_pages_range_noflush(), as these allocation failures are not fatal anymore. Reported-by: Dipanjan Das Link: https://lore.kernel.org/linux-mm/CANX2M5ZRrRA64k0hOif02TjmY9kbbO2aCBPyq79es34RXZ=cAw@mail.gmail.com/ Fixes: b073d7f8aee4 ("mm: kmsan: maintain KMSAN metadata for page operations") Signed-off-by: Alexander Potapenko --- include/linux/kmsan.h | 19 ++++++++++--------- mm/kmsan/shadow.c | 27 ++++++++++++++++++--------- mm/vmalloc.c | 6 +++++- 3 files changed, 33 insertions(+), 19 deletions(-) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index e38ae3c346184..a0769d4aad1c8 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -134,11 +134,12 @@ void kmsan_kfree_large(const void *ptr); * @page_shift: page_shift passed to vmap_range_noflush(). * * KMSAN maps shadow and origin pages of @pages into contiguous ranges in - * vmalloc metadata address range. + * vmalloc metadata address range. Returns 0 on success, callers must check + * for non-zero return value. */ -void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, - pgprot_t prot, struct page **pages, - unsigned int page_shift); +int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift); /** * kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap. @@ -281,11 +282,11 @@ static inline void kmsan_kfree_large(const void *ptr) { } -static inline void kmsan_vmap_pages_range_noflush(unsigned long start, - unsigned long end, - pgprot_t prot, - struct page **pages, - unsigned int page_shift) +static inline int kmsan_vmap_pages_range_noflush(unsigned long start, + unsigned long end, + pgprot_t prot, + struct page **pages, + unsigned int page_shift) { } diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c index a787c04e9583c..b8bb95eea5e3d 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -216,27 +216,29 @@ void kmsan_free_page(struct page *page, unsigned int order) kmsan_leave_runtime(); } -void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, - pgprot_t prot, struct page **pages, - unsigned int page_shift) +int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift) { unsigned long shadow_start, origin_start, shadow_end, origin_end; struct page **s_pages, **o_pages; - int nr, mapped; + int nr, mapped, err = 0; if (!kmsan_enabled) - return; + return 0; shadow_start = vmalloc_meta((void *)start, KMSAN_META_SHADOW); shadow_end = vmalloc_meta((void *)end, KMSAN_META_SHADOW); if (!shadow_start) - return; + return 0; nr = (end - start) / PAGE_SIZE; s_pages = kcalloc(nr, sizeof(*s_pages), GFP_KERNEL); o_pages = kcalloc(nr, sizeof(*o_pages), GFP_KERNEL); - if (!s_pages || !o_pages) + if (!s_pages || !o_pages) { + err = -ENOMEM; goto ret; + } for (int i = 0; i < nr; i++) { s_pages[i] = shadow_page_for(pages[i]); o_pages[i] = origin_page_for(pages[i]); @@ -249,10 +251,16 @@ void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, kmsan_enter_runtime(); mapped = __vmap_pages_range_noflush(shadow_start, shadow_end, prot, s_pages, page_shift); - KMSAN_WARN_ON(mapped); + if (mapped) { + err = mapped; + goto ret; + } mapped = __vmap_pages_range_noflush(origin_start, origin_end, prot, o_pages, page_shift); - KMSAN_WARN_ON(mapped); + if (mapped) { + err = mapped; + goto ret; + } kmsan_leave_runtime(); flush_tlb_kernel_range(shadow_start, shadow_end); flush_tlb_kernel_range(origin_start, origin_end); @@ -262,6 +270,7 @@ void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, ret: kfree(s_pages); kfree(o_pages); + return err; } /* Allocate metadata for pages allocated at boot time. */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index a50072066221a..1355d95cce1ca 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -605,7 +605,11 @@ int __vmap_pages_range_noflush(unsigned long addr, unsigned long end, int vmap_pages_range_noflush(unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, unsigned int page_shift) { - kmsan_vmap_pages_range_noflush(addr, end, prot, pages, page_shift); + int ret = kmsan_vmap_pages_range_noflush(addr, end, prot, pages, + page_shift); + + if (ret) + return ret; return __vmap_pages_range_noflush(addr, end, prot, pages, page_shift); } -- 2.40.0.577.gac1e443424-goog