From nobody Tue Feb 10 06:06:20 2026 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 9FF6FC77B7C for ; Fri, 12 May 2023 02:25:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239624AbjELCZl (ORCPT ); Thu, 11 May 2023 22:25:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239158AbjELCZj (ORCPT ); Thu, 11 May 2023 22:25:39 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7ECB359D0 for ; Thu, 11 May 2023 19:25:37 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-ba6939e78a0so10147748276.0 for ; Thu, 11 May 2023 19:25:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1683858336; x=1686450336; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=dVrdsQc/biAwpt188V4iZWfS19eaXCE07QPOY9kbdyc=; b=GQ8UVH9IygDETvgeENJQeoTFRl8IK6C71cn0eEf8SRe+fcNkVbogqZTEV5spZj3AYl QZY1fCTKrPPA3LJqQI2S73wLreGYzUHXWf6jF0T3V0Qu2J4n42ehYtbxn6HfNim8BzQ1 XB9T4j5TtAct937a1GogPDZ/VyvmPySCrq9ascVSC6HrVysL7S+Dup0RfS+TdHzyffYu +BWPKv5kR//I9uGLkkmM1C3DClzHSfgrHLothXTbfzQ5CPksh3m7s891AsCXvqTXm/Y2 A1ieQSQhQR+UsriiFUS5QNIen/0Zzln7A3aNqNaK8dDOFZlLywHR3jGaZiAOcllmGMaW 5X+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683858336; x=1686450336; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=dVrdsQc/biAwpt188V4iZWfS19eaXCE07QPOY9kbdyc=; b=Q8S6U8Ljxy8eJo0tqVo6JzgJD/McSSiBTZZpvvgltDMAQ5ZmjyJmbLCoXp8tAGlrvQ k+YxpJNJ0rcdghSJb06rFiiF/ePIwlliHrUSzBaGo9AZP6sTgid9M08pteQwhkB5wK3j GBQpxU/wWFL7E2BmrihYAJ1LRuqhn1Y3+VNfmM3F6w6NozQpg2wOD3sZiTKAjkRUTHF2 fuVhT5u/pMEsu8HGmUZAhlLtj2bSkOhFPtSlkvfYz4xBUPgjjpYog/s23s9icEW5I4Uh SnujS2kGGAdpER1RvQk9n0W0PnuVdNKu51Vlt7mrq7HphvkWJF42XOGciPfLXvHXhyyf EJKg== X-Gm-Message-State: AC+VfDzePwuAnW37aEVexvUFtIr6XEm9BoA/MN6jcXUAh4MTRqZkInwM TmsywJcCz0OEvEC3z3HSbljrES93AJhG X-Google-Smtp-Source: ACHHUZ6PjgAnQ4yHVTWsepQlN0qPo9uDN+LDYTHYcGjsv2wb8UltmdJTc0fhG08ccIWbq0MSRLcoxeq80x19 X-Received: from meowing-l.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:3eba]) (user=maskray job=sendgmr) by 2002:a05:690c:10c:b0:55c:a5db:869 with SMTP id bd12-20020a05690c010c00b0055ca5db0869mr19325168ywb.4.1683858336753; Thu, 11 May 2023 19:25:36 -0700 (PDT) Date: Fri, 12 May 2023 02:25:28 +0000 Mime-Version: 1.0 Message-ID: <20230512022528.3430327-1-maskray@google.com> Subject: [PATCH] coredump, vmcore: Set p_align to 4 for PT_NOTE From: Fangrui Song To: Alexander Viro , Christian Brauner , Eric Biederman , Kees Cook , Baoquan He , Vivek Goyal , Dave Young , linux-fsdevel@vger.kernel.org, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, Fangrui Song Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Tools like readelf/llvm-readelf use p_align to parse a PT_NOTE program header as an array of 4-byte entries or 8-byte entries. Currently, there are workarounds[1] in place for Linux to treat p_align=3D=3D0 as 4. However, it would be more appropriate to set the correct alignment so that tools do not have to rely on guesswork. FreeBSD coredumps set p_align to 4 as well. [1]: https://sourceware.org/git/?p=3Dbinutils-gdb.git;a=3Dcommit;h=3D82ed96= 83ec099d8205dc499ac84febc975235af6 [2]: https://reviews.llvm.org/D150022 --- fs/binfmt_elf.c | 2 +- fs/binfmt_elf_fdpic.c | 2 +- fs/proc/vmcore.c | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 1033fbdfdbec..44b4c42ab8e8 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1517,7 +1517,7 @@ static void fill_elf_note_phdr(struct elf_phdr *phdr,= int sz, loff_t offset) phdr->p_filesz =3D sz; phdr->p_memsz =3D 0; phdr->p_flags =3D 0; - phdr->p_align =3D 0; + phdr->p_align =3D 4; } =20 static void fill_note(struct memelfnote *note, const char *name, int type, diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 05a1471d5283..d76ad3d4f676 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1269,7 +1269,7 @@ static inline void fill_elf_note_phdr(struct elf_phdr= *phdr, int sz, loff_t offs phdr->p_filesz =3D sz; phdr->p_memsz =3D 0; phdr->p_flags =3D 0; - phdr->p_align =3D 0; + phdr->p_align =3D 4; return; } =20 diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 03f5963914a1..cb80a7703d58 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -877,7 +877,7 @@ static int __init merge_note_headers_elf64(char *elfptr= , size_t *elfsz, phdr.p_offset =3D roundup(note_off, PAGE_SIZE); phdr.p_vaddr =3D phdr.p_paddr =3D 0; phdr.p_filesz =3D phdr.p_memsz =3D phdr_sz; - phdr.p_align =3D 0; + phdr.p_align =3D 4; =20 /* Add merged PT_NOTE program header*/ tmp =3D elfptr + sizeof(Elf64_Ehdr); @@ -1068,7 +1068,7 @@ static int __init merge_note_headers_elf32(char *elfp= tr, size_t *elfsz, phdr.p_offset =3D roundup(note_off, PAGE_SIZE); phdr.p_vaddr =3D phdr.p_paddr =3D 0; phdr.p_filesz =3D phdr.p_memsz =3D phdr_sz; - phdr.p_align =3D 0; + phdr.p_align =3D 4; =20 /* Add merged PT_NOTE program header*/ tmp =3D elfptr + sizeof(Elf32_Ehdr); --=20 2.40.1.606.ga4b1b128d6-goog