Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964783AbcKDPnQ (ORCPT ); Fri, 4 Nov 2016 11:43:16 -0400 Received: from mail-wm0-f48.google.com ([74.125.82.48]:37605 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935438AbcKDPnO (ORCPT ); Fri, 4 Nov 2016 11:43:14 -0400 From: Jakub Kicinski To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-arch@vger.kernel.org, Arnd Bergmann , Andrew Morton , Cong Wang , Johannes Berg , Jakub Kicinski Subject: [PATCH] mm: kmemleak: scan .data.ro_after_init Date: Fri, 4 Nov 2016 15:42:53 +0000 Message-Id: <1478274173-15218-1-git-send-email-jakub.kicinski@netronome.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3217 Lines: 86 Limit number of kmemleak's false positives by including .data.ro_after_init in memory scanning. To achieve this we need to add symbols for start and end of the section to the linker scripts. The problem has been uncovered by commit 56989f6d8568 ("genetlink: mark families as __ro_after_init"). Signed-off-by: Jakub Kicinski Reviewed-by: Catalin Marinas --- Since the RFC I dropped the use of VMLINUX_SYMBOL(). Please advise if it should be added back. --- arch/s390/kernel/vmlinux.lds.S | 2 ++ include/asm-generic/sections.h | 3 +++ include/asm-generic/vmlinux.lds.h | 5 ++++- mm/kmemleak.c | 1 + 4 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index 000e6e91f6a0..3667d20e997f 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -62,9 +62,11 @@ SECTIONS . = ALIGN(PAGE_SIZE); __start_ro_after_init = .; + __start_data_ro_after_init = .; .data..ro_after_init : { *(.data..ro_after_init) } + __end_data_ro_after_init = .; EXCEPTION_TABLE(16) . = ALIGN(PAGE_SIZE); __end_ro_after_init = .; diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index af0254c09424..4df64a1fc09e 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -14,6 +14,8 @@ * [_sdata, _edata]: contains .data.* sections, may also contain .rodata.* * and/or .init.* sections. * [__start_rodata, __end_rodata]: contains .rodata.* sections + * [__start_data_ro_after_init, __end_data_ro_after_init]: + * contains data.ro_after_init section * [__init_begin, __init_end]: contains .init.* sections, but .init.text.* * may be out of this range on some architectures. * [_sinittext, _einittext]: contains .init.text.* sections @@ -31,6 +33,7 @@ extern char __bss_start[], __bss_stop[]; extern char __init_begin[], __init_end[]; extern char _sinittext[], _einittext[]; +extern char __start_data_ro_after_init[], __end_data_ro_after_init[]; extern char _end[]; extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[]; extern char __kprobes_text_start[], __kprobes_text_end[]; diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 30747960bc54..31e1d639abed 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -259,7 +259,10 @@ * own by defining an empty RO_AFTER_INIT_DATA. */ #ifndef RO_AFTER_INIT_DATA -#define RO_AFTER_INIT_DATA *(.data..ro_after_init) +#define RO_AFTER_INIT_DATA \ + __start_data_ro_after_init = .; \ + *(.data..ro_after_init) \ + __end_data_ro_after_init = .; #endif /* diff --git a/mm/kmemleak.c b/mm/kmemleak.c index e5355a5b423f..d1380ed93fdf 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1414,6 +1414,7 @@ static void kmemleak_scan(void) /* data/bss scanning */ scan_large_block(_sdata, _edata); scan_large_block(__bss_start, __bss_stop); + scan_large_block(__start_data_ro_after_init, __end_data_ro_after_init); #ifdef CONFIG_SMP /* per-cpu sections scanning */ -- 1.9.1