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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 C3306C433DF for ; Fri, 16 Oct 2020 03:12:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 835E82087D for ; Fri, 16 Oct 2020 03:12:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602817969; bh=RMS12A4AtH/1vvv7s/wdNxUJAowc/hTRWWqacDlOe7A=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=I3hTnrFYO/yQL7SWIHtJHfmDHOpXb7hYCvumaCkrCNoBKdNfeAPAxe/G5PlZVhJyo urOPgKBK66+Nl3NnlLD7aFWsrRCvMzbBkvcwTxSDKeKCVdrOxhb9REKFkNPqqG8V2j Xya2YFX7wu0DOIKIdr7/anNZFUrGrdtbjxJiv/0M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390137AbgJPDMt (ORCPT ); Thu, 15 Oct 2020 23:12:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:48718 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389908AbgJPDMt (ORCPT ); Thu, 15 Oct 2020 23:12:49 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 57A4C2083B; Fri, 16 Oct 2020 03:12:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602817967; bh=RMS12A4AtH/1vvv7s/wdNxUJAowc/hTRWWqacDlOe7A=; h=Date:From:To:Subject:In-Reply-To:From; b=rnYx+1pkDodi/6kjLRqwvlhaclQrVkyH3L3eT8lOd8kLIfKTT+EImhbAfNEkR4XUj 5NW3pkaER6I7WDKCU3BYLyCAShiJK8nRj7cWUDUp8ugyxTlWzivqIwxhl1Dc5CVhYl L6DjyvKG6P+A4FEUuEddpC5W3johIZNJlfC/X3aQ= Date: Thu, 15 Oct 2020 20:12:46 -0700 From: Andrew Morton To: akpm@linux-foundation.org, ebiederm@xmission.com, hch@lst.de, hughd@google.com, jannh@google.com, mm-commits@vger.kernel.org, oleg@redhat.com, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk Subject: [patch 138/156] coredump: refactor page range dumping into common helper Message-ID: <20201016031246.pQ_cwOgRv%akpm@linux-foundation.org> In-Reply-To: <20201015194043.84cda0c1d6ca2a6847f2384a@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Jann Horn Subject: coredump: refactor page range dumping into common helper 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. Link: http://lkml.kernel.org/r/20200827114932.3572699-4-jannh@google.com Signed-off-by: Jann Horn Acked-by: Linus Torvalds Cc: Christoph Hellwig Cc: Alexander Viro Cc: "Eric W . Biederman" Cc: Oleg Nesterov Cc: Hugh Dickins Signed-off-by: Andrew Morton --- 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(-) --- a/fs/binfmt_elf.c~coredump-refactor-page-range-dumping-into-common-helper +++ a/fs/binfmt_elf.c @@ -2444,26 +2444,8 @@ static int elf_core_dump(struct coredump 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); --- a/fs/binfmt_elf_fdpic.c~coredump-refactor-page-range-dumping-into-common-helper +++ a/fs/binfmt_elf_fdpic.c @@ -1534,21 +1534,9 @@ static bool elf_fdpic_dump_segments(stru 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; } --- a/fs/coredump.c~coredump-refactor-page-range-dumping-into-common-helper +++ a/fs/coredump.c @@ -876,6 +876,40 @@ int dump_skip(struct coredump_params *cp } 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); --- a/include/linux/coredump.h~coredump-refactor-page-range-dumping-into-common-helper +++ a/include/linux/coredump.h @@ -16,6 +16,8 @@ extern int dump_skip(struct coredump_par 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 _