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 X-Spam-Level: X-Spam-Status: No, score=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A687AC433E3 for ; Tue, 18 Aug 2020 06:13:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 816AB2075B for ; Tue, 18 Aug 2020 06:13:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ScWCp387" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726685AbgHRGNE (ORCPT ); Tue, 18 Aug 2020 02:13:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726646AbgHRGM6 (ORCPT ); Tue, 18 Aug 2020 02:12:58 -0400 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17988C061342 for ; Mon, 17 Aug 2020 23:12:58 -0700 (PDT) Received: by mail-qk1-x74a.google.com with SMTP id 195so12440619qke.14 for ; Mon, 17 Aug 2020 23:12:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=BQ6deNARx/tr049/coZN1ctnBsmm6qw6/g2K/OuqjPA=; b=ScWCp387mFONX1TRBXREQ33OJC79OiceR3AT7pe+fbYNruJ/cF79js7PVNcKdsqPDZ BTp7uhi1083v5EBt6Uppic6CT6DkZCElwoMRkhSSYggi6vKf9l4WpEIlB6RERBTJMNdM fZiO3/eIHW3UfOorwOBSFG5F2PsfxLoTtZ87LvIKmkzN27a8Xuwr7Y31057R2GF+aJHX 93E/1L9ITCo5UiEqejSGzxniroi3FHAYidFVlj72bQrHMtWuBkFNxUEW9YMRz2enbLSV G8/0r/4ylw5EbaG706fv6kMwkKApmrMMjh8P8HRffVbxfy0gyZcd1IpInr1gQGk7qJS5 vjoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=BQ6deNARx/tr049/coZN1ctnBsmm6qw6/g2K/OuqjPA=; b=L8xTn8+OKeRlU405Yj1lmOLVTdPBTvAgjXLaNzD9QVEXb2joQlEblEqVt0iTUYnyco v9Ckgzjb+dK1Ci90+BE3gNt/rxVkIkwJB1uNX768x+t2ELlOLAF7CtKnjqs/Xeo/23Mt ZBrkmN0VlAdnE9nEmrj7dWLHHDdt3KiSg0LrTU55dEQmA7zEvLv59yj9V0JlBO2F3oY4 mCW4Xbs76eOHzjjcL+kMRBlmmZfcpT1H4OBGzQ8m1UkMuMWQf0BxDjOQjeH603uFtDV+ 2HDdJAoj+ezrsTNRAWuNYLMl/zroRmeTwvi18evnaSpEm3dLJzr7Wd3zVdk1erpL9bqd FGww== X-Gm-Message-State: AOAM530/HEMmCbobA7mbMexoo1VJWUL+v4qSys2pqMEhVNsrKrjc6jl2 U2F9fyG55LiH/v0i9MLC5tlqfXjpsQ== X-Google-Smtp-Source: ABdhPJyh/6VtzjvXkSvgr3+1RQjgt+P+1s2URdDDGUndrNNa2/EOYOf/bFUg8TykIbv7qlhxxhrVQHJBzA== X-Received: by 2002:ad4:4c0a:: with SMTP id bz10mr17004710qvb.78.1597731177252; Mon, 17 Aug 2020 23:12:57 -0700 (PDT) Date: Tue, 18 Aug 2020 08:12:37 +0200 In-Reply-To: <20200818061239.29091-1-jannh@google.com> Message-Id: <20200818061239.29091-4-jannh@google.com> Mime-Version: 1.0 References: <20200818061239.29091-1-jannh@google.com> X-Mailer: git-send-email 2.28.0.220.ged08abb693-goog Subject: [PATCH v3 3/5] coredump: Refactor page range dumping into common helper From: Jann Horn To: Andrew Morton Cc: Linus Torvalds , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Alexander Viro , "Eric W . Biederman" , Oleg Nesterov Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Both fs/binfmt_elf.c and fs/binfmt_elf_fdpic.c need to dump ranges of pages into the coredump file. Extract that logic into a common helper. Signed-off-by: Jann Horn --- fs/binfmt_elf.c | 22 ++-------------------- fs/binfmt_elf_fdpic.c | 18 +++--------------- fs/coredump.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/coredump.h | 2 ++ 4 files changed, 41 insertions(+), 35 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 13d053982dd7..5fd11a25d320 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -2419,26 +2419,8 @@ static int elf_core_dump(struct coredump_params *cprm) for (i = 0, vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { - unsigned long addr; - unsigned long end; - - end = vma->vm_start + vma_filesz[i++]; - - for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) { - struct page *page; - int stop; - - page = get_dump_page(addr); - if (page) { - void *kaddr = kmap(page); - stop = !dump_emit(cprm, kaddr, PAGE_SIZE); - kunmap(page); - put_page(page); - } else - stop = !dump_skip(cprm, PAGE_SIZE); - if (stop) - goto end_coredump; - } + if (!dump_user_range(cprm, vma->vm_start, vma_filesz[i++])) + goto end_coredump; } dump_truncate(cprm); diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index a53f83830986..76e8c0defdc8 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1534,21 +1534,9 @@ static bool elf_fdpic_dump_segments(struct coredump_params *cprm) if (!maydump(vma, cprm->mm_flags)) continue; - for (addr = vma->vm_start; addr < vma->vm_end; - addr += PAGE_SIZE) { - bool res; - struct page *page = get_dump_page(addr); - if (page) { - void *kaddr = kmap(page); - res = dump_emit(cprm, kaddr, PAGE_SIZE); - kunmap(page); - put_page(page); - } else { - res = dump_skip(cprm, PAGE_SIZE); - } - if (!res) - return false; - } + if (!dump_user_range(cprm, vma->vm_start, + vma->vma_end - vma->vm_start)) + return false; } return true; } diff --git a/fs/coredump.c b/fs/coredump.c index 5e24c06092c9..6042d15acd51 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -876,6 +876,40 @@ int dump_skip(struct coredump_params *cprm, size_t nr) } EXPORT_SYMBOL(dump_skip); +#ifdef CONFIG_ELF_CORE +int dump_user_range(struct coredump_params *cprm, unsigned long start, + unsigned long len) +{ + unsigned long addr; + + for (addr = start; addr < start + len; addr += PAGE_SIZE) { + struct page *page; + int stop; + + /* + * To avoid having to allocate page tables for virtual address + * ranges that have never been used yet, and also to make it + * easy to generate sparse core files, use a helper that returns + * NULL when encountering an empty page table entry that would + * otherwise have been filled with the zero page. + */ + page = get_dump_page(addr); + if (page) { + void *kaddr = kmap(page); + + stop = !dump_emit(cprm, kaddr, PAGE_SIZE); + kunmap(page); + put_page(page); + } else { + stop = !dump_skip(cprm, PAGE_SIZE); + } + if (stop) + return 0; + } + return 1; +} +#endif + int dump_align(struct coredump_params *cprm, int align) { unsigned mod = cprm->pos & (align - 1); diff --git a/include/linux/coredump.h b/include/linux/coredump.h index 7a899e83835d..f0b71a74d0bc 100644 --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -16,6 +16,8 @@ extern int dump_skip(struct coredump_params *cprm, size_t nr); extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr); extern int dump_align(struct coredump_params *cprm, int align); extern void dump_truncate(struct coredump_params *cprm); +int dump_user_range(struct coredump_params *cprm, unsigned long start, + unsigned long len); #ifdef CONFIG_COREDUMP extern void do_coredump(const kernel_siginfo_t *siginfo); #else -- 2.28.0.220.ged08abb693-goog