From patchwork Fri Oct 16 02:49:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11840781 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B126514B4 for ; Fri, 16 Oct 2020 02:49:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6401A21527 for ; Fri, 16 Oct 2020 02:49:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="2ld42Ual" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6401A21527 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 57E97940070; Thu, 15 Oct 2020 22:49:45 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 507B894006D; Thu, 15 Oct 2020 22:49:45 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 41D17940070; Thu, 15 Oct 2020 22:49:45 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0102.hostedemail.com [216.40.44.102]) by kanga.kvack.org (Postfix) with ESMTP id 1153694006D for ; Thu, 15 Oct 2020 22:49:45 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B4613362A for ; Fri, 16 Oct 2020 02:49:44 +0000 (UTC) X-FDA: 77376258288.22.line22_220608927219 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin22.hostedemail.com (Postfix) with ESMTP id 92B3C18038E67 for ; Fri, 16 Oct 2020 02:49:44 +0000 (UTC) X-Spam-Summary: 1,0,0,72ce56861d2fdb7c,d41d8cd98f00b204,akpm@linux-foundation.org,,RULES_HIT:41:69:355:379:800:960:967:973:988:989:1260:1263:1345:1359:1381:1431:1437:1535:1544:1711:1730:1747:1777:1792:2393:2525:2559:2563:2682:2685:2859:2898:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3354:3865:3866:3867:3868:3872:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:4605:5007:6261:6653:7576:7904:7974:8599:9025:9545:9592:10004:10913:11026:11473:11658:11914:12043:12048:12291:12294:12296:12297:12438:12517:12519:12555:12679:12683:12783:12986:13846:14181:14721:14849:21080:21451:21627:21939:21990:30003:30054:30070,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-62.2.0.100 64.100.201.201;04yfy9ctnsxj17iexn9yhap849jkoopd5qta4fehgrdixipoaffque3p74bzgzj.ee7k4ifewfoohjnz3cggeznqh44qrcjeztrbnzxfabe1dmo6py5mj3ez3zjoy9r.n-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MS BL:0,DNS X-HE-Tag: line22_220608927219 X-Filterd-Recvd-Size: 5789 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Fri, 16 Oct 2020 02:49:44 +0000 (UTC) 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 AF18020897; Fri, 16 Oct 2020 02:49:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602816583; bh=RMS12A4AtH/1vvv7s/wdNxUJAowc/hTRWWqacDlOe7A=; h=Date:From:To:Subject:In-Reply-To:From; b=2ld42UaleJ1QOY/yNcVPpEOu/+v6hGf4fqCPLi2ycA2unwr3ep423FJhioXN9O996 pexhVNVUuZXQGt+H5kym7k1az9QnY5GB+exDO3JjAXLcbFiMfwLOvJDw23AG6dkVl+ oUvJmUG44OQoSGSlGRo9dugnk7X+HdMNT3gOWjnk= Date: Thu, 15 Oct 2020 19:49:42 -0700 From: Andrew Morton To: akpm@linux-foundation.org, ebiederm@xmission.com, hch@lst.de, hughd@google.com, jannh@google.com, linux-mm@kvack.org, 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: <20201016024942.n196Lyk6S%akpm@linux-foundation.org> In-Reply-To: <20201015192732.f448da14e9854c7cb7299956@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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