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mm: kmemleak: scan .data.ro_after_init

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Limit the number of kmemleak 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 was been uncovered by commit 56989f6d85 ("genetlink: mark
families as __ro_after_init").

Link: http://lkml.kernel.org/r/1478274173-15218-1-git-send-email-jakub.kicinski@netronome.com
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jakub Kicinski 2016-11-10 10:46:44 -08:00 committed by Linus Torvalds
parent f773e36de3
commit d7c19b066d
4 changed files with 10 additions and 1 deletions
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2
arch/s390/kernel/vmlinux.lds.S
View file

@ -62,9 +62,11 @@ SECTIONS
. = ALIGN(PAGE_SIZE); . = ALIGN(PAGE_SIZE);
__start_ro_after_init = .; __start_ro_after_init = .;
__start_data_ro_after_init = .;
.data..ro_after_init : { .data..ro_after_init : {
*(.data..ro_after_init) *(.data..ro_after_init)
} }
__end_data_ro_after_init = .;
EXCEPTION_TABLE(16) EXCEPTION_TABLE(16)
. = ALIGN(PAGE_SIZE); . = ALIGN(PAGE_SIZE);
__end_ro_after_init = .; __end_ro_after_init = .;

3
include/asm-generic/sections.h
View file

@ -14,6 +14,8 @@
* [_sdata, _edata]: contains .data.* sections, may also contain .rodata.* * [_sdata, _edata]: contains .data.* sections, may also contain .rodata.*
* and/or .init.* sections. * and/or .init.* sections.
* [__start_rodata, __end_rodata]: contains .rodata.* 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.* * [__init_begin, __init_end]: contains .init.* sections, but .init.text.*
* may be out of this range on some architectures. * may be out of this range on some architectures.
* [_sinittext, _einittext]: contains .init.text.* sections * [_sinittext, _einittext]: contains .init.text.* sections
@ -31,6 +33,7 @@ extern char _data[], _sdata[], _edata[];
extern char __bss_start[], __bss_stop[]; extern char __bss_start[], __bss_stop[];
extern char __init_begin[], __init_end[]; extern char __init_begin[], __init_end[];
extern char _sinittext[], _einittext[]; extern char _sinittext[], _einittext[];
extern char __start_data_ro_after_init[], __end_data_ro_after_init[];
extern char _end[]; extern char _end[];
extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[]; extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
extern char __kprobes_text_start[], __kprobes_text_end[]; extern char __kprobes_text_start[], __kprobes_text_end[];

5
include/asm-generic/vmlinux.lds.h
View file

@ -259,7 +259,10 @@
* own by defining an empty RO_AFTER_INIT_DATA. * own by defining an empty RO_AFTER_INIT_DATA.
*/ */
#ifndef 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 #endif
/* /*

1
mm/kmemleak.c
View file

@ -1414,6 +1414,7 @@ static void kmemleak_scan(void)
/* data/bss scanning */ /* data/bss scanning */
scan_large_block(_sdata, _edata); scan_large_block(_sdata, _edata);
scan_large_block(__bss_start, __bss_stop); scan_large_block(__bss_start, __bss_stop);
scan_large_block(__start_data_ro_after_init, __end_data_ro_after_init);
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
/* per-cpu sections scanning */ /* per-cpu sections scanning */