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=-3.8 required=3.0 tests=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 62FA6C33CB2 for ; Fri, 31 Jan 2020 06:17:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 187F72173E for ; Fri, 31 Jan 2020 06:17:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="wCSOburB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 187F72173E 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 AC9C56B0593; Fri, 31 Jan 2020 01:17:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9B5616B0595; Fri, 31 Jan 2020 01:17:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 87CD56B0596; Fri, 31 Jan 2020 01:17:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0157.hostedemail.com [216.40.44.157]) by kanga.kvack.org (Postfix) with ESMTP id 6C1806B0593 for ; Fri, 31 Jan 2020 01:17:06 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 27F8D45A0 for ; Fri, 31 Jan 2020 06:17:06 +0000 (UTC) X-FDA: 76436921652.07.sense20_3df818309672f X-HE-Tag: sense20_3df818309672f X-Filterd-Recvd-Size: 3993 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Fri, 31 Jan 2020 06:17:05 +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 001772173E; Fri, 31 Jan 2020 06:17:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580451425; bh=59cMRDc+zrkr/IU/LY0n2IOfn55gRyGTlf91TW8GdgE=; h=Date:From:To:Subject:In-Reply-To:From; b=wCSOburB4oguBFhJ5gFiYDObZ393YpaJUbiz2fLZoJ4Cn7F5m4k+odxWzsxlW1/eC UPMav/UhUumekpqdbTnp4Fuw3iGBmm28oj4jzXnnyIdYallT6PHs2UehUQEkwYMkCp aZKeuzZhu5Ow/xwaeI00jRSMtCo+eXo9PnCYfZUw= Date: Thu, 30 Jan 2020 22:17:04 -0800 From: Andrew Morton To: adobriyan@gmail.com, akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 108/118] fs/binfmt_elf.c: coredump: allocate core ELF header on stack Message-ID: <20200131061704.DHU7ngwKs%akpm@linux-foundation.org> In-Reply-To: <20200130221021.5f0211c56346d5485af07923@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: Alexey Dobriyan Subject: fs/binfmt_elf.c: coredump: allocate core ELF header on stack Comment says ELF header is "too large to be on stack". 64 bytes on 64-bit is not large by any means. Link: http://lkml.kernel.org/r/20191222143850.GA24341@avx2 Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton --- fs/binfmt_elf.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) --- a/fs/binfmt_elf.c~elf-coredump-allocate-core-elf-header-on-stack +++ a/fs/binfmt_elf.c @@ -2186,7 +2186,7 @@ static int elf_core_dump(struct coredump int segs, i; size_t vma_data_size = 0; struct vm_area_struct *vma, *gate_vma; - struct elfhdr *elf = NULL; + struct elfhdr elf; loff_t offset = 0, dataoff; struct elf_note_info info = { }; struct elf_phdr *phdr4note = NULL; @@ -2207,10 +2207,6 @@ static int elf_core_dump(struct coredump * exists while dumping the mm->vm_next areas to the core file. */ - /* alloc memory for large data structures: too large to be on stack */ - elf = kmalloc(sizeof(*elf), GFP_KERNEL); - if (!elf) - goto out; /* * The number of segs are recored into ELF header as 16bit value. * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here. @@ -2234,7 +2230,7 @@ static int elf_core_dump(struct coredump * Collect all the non-memory information about the process for the * notes. This also sets up the file header. */ - if (!fill_note_info(elf, e_phnum, &info, cprm->siginfo, cprm->regs)) + if (!fill_note_info(&elf, e_phnum, &info, cprm->siginfo, cprm->regs)) goto cleanup; has_dumped = 1; @@ -2242,7 +2238,7 @@ static int elf_core_dump(struct coredump fs = get_fs(); set_fs(KERNEL_DS); - offset += sizeof(*elf); /* Elf header */ + offset += sizeof(elf); /* Elf header */ offset += segs * sizeof(struct elf_phdr); /* Program headers */ /* Write notes phdr entry */ @@ -2285,12 +2281,12 @@ static int elf_core_dump(struct coredump shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL); if (!shdr4extnum) goto end_coredump; - fill_extnum_info(elf, shdr4extnum, e_shoff, segs); + fill_extnum_info(&elf, shdr4extnum, e_shoff, segs); } offset = dataoff; - if (!dump_emit(cprm, elf, sizeof(*elf))) + if (!dump_emit(cprm, &elf, sizeof(elf))) goto end_coredump; if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note))) @@ -2374,8 +2370,6 @@ cleanup: kfree(shdr4extnum); kvfree(vma_filesz); kfree(phdr4note); - kfree(elf); -out: return has_dumped; } _