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 75D97C77B6F for ; Thu, 13 Apr 2023 13:12:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230370AbjDMNMv (ORCPT ); Thu, 13 Apr 2023 09:12:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230316AbjDMNMs (ORCPT ); Thu, 13 Apr 2023 09:12:48 -0400 Received: from mail-wm1-x34a.google.com (mail-wm1-x34a.google.com [IPv6:2a00:1450:4864:20::34a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94913A26F for ; Thu, 13 Apr 2023 06:12:32 -0700 (PDT) Received: by mail-wm1-x34a.google.com with SMTP id m7-20020a05600c3b0700b003ee112e6df1so4774989wms.2 for ; Thu, 13 Apr 2023 06:12:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1681391551; x=1683983551; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=akRe6e4LluVT6nSisjA8EFH4R71lf+zwEBXmk0EhBro=; b=UWMmjgu4IOSqX5O5xqqvwkH7RA1XeATrgudE5npO4wFN2DVyqyLAVKX22J9okhAt/f WotKPxEQVCFGgD5uRAwrTZUlIEZ/IsbLrld0fd3ZNx6+fnGYgn6BFkHWg+tR5TuM3i/2 /QxA1eaUKLWaI7yosX5HLTbRHZPPs9eytyhZr7c+VI11gRjnyGympvKbf2DjnClcTAeZ jMHfSvmsDhUshFLa9aTwnqaCvBr5xvm37uTdVsG/JwEBAxP/7+CABtpGpFdswDI8yGf6 rlZFmxJpt+if/yKAmeqXtLu4so+aQiQ3pC2KmSbses/Xm3lEXWcn2I/t7g7IAXvH2OlP 1pwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681391551; x=1683983551; 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=akRe6e4LluVT6nSisjA8EFH4R71lf+zwEBXmk0EhBro=; b=B3NdbFw02s4L3i5TT9byQml3r1lkLntpemGUL5DGE/pyVGdb4KY9hqNghDMIY5zf+6 cnf+JXu8TK3VyqxY+tbBUIqiJzzuC5oNJ87T8ptciqdIqJR9c0vm3lCjLwIKwKGZCkbl o5WXtFs8V8w1BngwPs/bhVPqK/bLdFQthUUZeeraB0QI81A+xrVBRf41d/6HgSQn6FFT IJvPmeegaIDGTErVPuZpy1ZKGTg6eUQ7qQxFXRMgoiboYDDlwVfIkSUoDtbTd40wTGna 3ZdVBSy80RBGXXjDD+CLkSupcwIzTI+Zixo6PUWdSd3rqN0/qYaye7XdjTm4xf/l1K/U MeJA== X-Gm-Message-State: AAQBX9fxbjjIvy6pE77yukuF8t8mS0NixzlsqzrvabcvUZiv6pHuWia4 TjsWpbFyRYdcZ+h6UJ3bmEk8T+J60y8= X-Google-Smtp-Source: AKy350aXlH+JEH6G36TukQUXMTmo+3/5cJ7SYgjh19063ZjyiBg+1zGqVChNDLCI/LK5ak77r2MOdwY/dZk= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:eb2b:4d7d:1d7f:9316]) (user=glider job=sendgmr) by 2002:a5d:4a42:0:b0:2f2:7854:f419 with SMTP id v2-20020a5d4a42000000b002f27854f419mr325850wrs.13.1681391551064; Thu, 13 Apr 2023 06:12:31 -0700 (PDT) Date: Thu, 13 Apr 2023 15:12:21 +0200 In-Reply-To: <20230413131223.4135168-1-glider@google.com> Mime-Version: 1.0 References: <20230413131223.4135168-1-glider@google.com> X-Mailer: git-send-email 2.40.0.577.gac1e443424-goog Message-ID: <20230413131223.4135168-2-glider@google.com> Subject: [PATCH v2 2/4] mm: kmsan: handle alloc failures in kmsan_ioremap_page_range() 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 Similarly to kmsan_vmap_pages_range_noflush(), kmsan_ioremap_page_range() must also properly handle allocation/mapping failures. In the case of such, it must clean up the already created metadata mappings and return an error code, so that the error can be propagated to ioremap_page_range(). Without doing so, KMSAN may silently fail to bring the metadata for the page range into a consistent state, which will result in user-visible crashes when trying to access them. 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 --- v2: -- updated patch description as requested by Andrew Morton -- check the return value of __vmap_pages_range_noflush(), as suggested by Dipanjan Das -- return 0 from the inline version of kmsan_ioremap_page_range() (spotted by kernel test robot ) --- include/linux/kmsan.h | 19 ++++++++------- mm/kmsan/hooks.c | 55 ++++++++++++++++++++++++++++++++++++------- mm/vmalloc.c | 4 ++-- 3 files changed, 59 insertions(+), 19 deletions(-) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index c7ff3aefc5a13..30b17647ce3c7 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -160,11 +160,12 @@ void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end); * @page_shift: page_shift argument passed to vmap_range_noflush(). * * KMSAN creates new metadata pages for the physical pages mapped into the - * virtual memory. + * virtual memory. Returns 0 on success, callers must check for non-zero return + * value. */ -void kmsan_ioremap_page_range(unsigned long addr, unsigned long end, - phys_addr_t phys_addr, pgprot_t prot, - unsigned int page_shift); +int kmsan_ioremap_page_range(unsigned long addr, unsigned long end, + phys_addr_t phys_addr, pgprot_t prot, + unsigned int page_shift); /** * kmsan_iounmap_page_range() - Notify KMSAN about a iounmap_page_range() call. @@ -296,12 +297,12 @@ static inline void kmsan_vunmap_range_noflush(unsigned long start, { } -static inline void kmsan_ioremap_page_range(unsigned long start, - unsigned long end, - phys_addr_t phys_addr, - pgprot_t prot, - unsigned int page_shift) +static inline int kmsan_ioremap_page_range(unsigned long start, + unsigned long end, + phys_addr_t phys_addr, pgprot_t prot, + unsigned int page_shift) { + return 0; } static inline void kmsan_iounmap_page_range(unsigned long start, diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index 3807502766a3e..ec0da72e65aa0 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -148,35 +148,74 @@ void kmsan_vunmap_range_noflush(unsigned long start, unsigned long end) * into the virtual memory. If those physical pages already had shadow/origin, * those are ignored. */ -void kmsan_ioremap_page_range(unsigned long start, unsigned long end, - phys_addr_t phys_addr, pgprot_t prot, - unsigned int page_shift) +int kmsan_ioremap_page_range(unsigned long start, unsigned long end, + phys_addr_t phys_addr, pgprot_t prot, + unsigned int page_shift) { gfp_t gfp_mask = GFP_KERNEL | __GFP_ZERO; struct page *shadow, *origin; unsigned long off = 0; - int nr; + int nr, err = 0, clean = 0, mapped; if (!kmsan_enabled || kmsan_in_runtime()) - return; + return 0; nr = (end - start) / PAGE_SIZE; kmsan_enter_runtime(); - for (int i = 0; i < nr; i++, off += PAGE_SIZE) { + for (int i = 0; i < nr; i++, off += PAGE_SIZE, clean = i) { shadow = alloc_pages(gfp_mask, 1); origin = alloc_pages(gfp_mask, 1); - __vmap_pages_range_noflush( + if (!shadow || !origin) { + err = -ENOMEM; + goto ret; + } + mapped = __vmap_pages_range_noflush( vmalloc_shadow(start + off), vmalloc_shadow(start + off + PAGE_SIZE), prot, &shadow, PAGE_SHIFT); - __vmap_pages_range_noflush( + if (mapped) { + err = mapped; + goto ret; + } + shadow = NULL; + mapped = __vmap_pages_range_noflush( vmalloc_origin(start + off), vmalloc_origin(start + off + PAGE_SIZE), prot, &origin, PAGE_SHIFT); + if (mapped) { + __vunmap_range_noflush( + vmalloc_shadow(start + off), + vmalloc_shadow(start + off + PAGE_SIZE)); + err = mapped; + goto ret; + } + origin = NULL; + } + /* Page mapping loop finished normally, nothing to clean up. */ + clean = 0; + +ret: + if (clean > 0) { + /* + * Something went wrong. Clean up shadow/origin pages allocated + * on the last loop iteration, then delete mappings created + * during the previous iterations. + */ + if (shadow) + __free_pages(shadow, 1); + if (origin) + __free_pages(origin, 1); + __vunmap_range_noflush( + vmalloc_shadow(start), + vmalloc_shadow(start + clean * PAGE_SIZE)); + __vunmap_range_noflush( + vmalloc_origin(start), + vmalloc_origin(start + clean * PAGE_SIZE)); } flush_cache_vmap(vmalloc_shadow(start), vmalloc_shadow(end)); flush_cache_vmap(vmalloc_origin(start), vmalloc_origin(end)); kmsan_leave_runtime(); + return err; } void kmsan_iounmap_page_range(unsigned long start, unsigned long end) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 1355d95cce1ca..31ff782d368b0 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -313,8 +313,8 @@ int ioremap_page_range(unsigned long addr, unsigned long end, ioremap_max_page_shift); flush_cache_vmap(addr, end); if (!err) - kmsan_ioremap_page_range(addr, end, phys_addr, prot, - ioremap_max_page_shift); + err = kmsan_ioremap_page_range(addr, end, phys_addr, prot, + ioremap_max_page_shift); return err; } -- 2.40.0.577.gac1e443424-goog