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Qian Cai 9e15afa5a8 mm/page_alloc: silence a KASAN false positive
kernel_init_free_pages() will use memset() on s390 to clear all pages from
kmalloc_order() which will override KASAN redzones because a redzone was
setup from the end of the allocation size to the end of the last page.
Silence it by not reporting it there.  An example of the report is,

 BUG: KASAN: slab-out-of-bounds in __free_pages_ok
 Write of size 4096 at addr 000000014beaa000
 Call Trace:
 show_stack+0x152/0x210
 dump_stack+0x1f8/0x248
 print_address_description.isra.13+0x5e/0x4d0
 kasan_report+0x130/0x178
 check_memory_region+0x190/0x218
 memset+0x34/0x60
 __free_pages_ok+0x894/0x12f0
 kfree+0x4f2/0x5e0
 unpack_to_rootfs+0x60e/0x650
 populate_rootfs+0x56/0x358
 do_one_initcall+0x1f4/0xa20
 kernel_init_freeable+0x758/0x7e8
 kernel_init+0x1c/0x170
 ret_from_fork+0x24/0x28
 Memory state around the buggy address:
 000000014bea9f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 000000014bea9f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>000000014beaa000: 03 fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
                    ^
 000000014beaa080: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 000000014beaa100: fe fe fe fe fe fe fe fe fe fe fe fe fe fe

Fixes: 6471384af2 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options")
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Link: http://lkml.kernel.org/r/20200610052154.5180-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:29 -07:00
arch kasan, arm64: don't instrument functions that enable kasan 2020-08-07 11:33:28 -07:00
block for-5.9/block-merge-20200804 2020-08-05 11:12:34 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
Documentation kasan: update documentation for generic kasan 2020-08-07 11:33:28 -07:00
drivers mm: remove unneeded includes of <asm/pgalloc.h> 2020-08-07 11:33:26 -07:00
fs mm: remove unnecessary wrapper function do_mmap_pgoff() 2020-08-07 11:33:27 -07:00
include mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask() 2020-08-07 11:33:29 -07:00
init kasan, arm64: don't instrument functions that enable kasan 2020-08-07 11:33:28 -07:00
ipc mm: remove unnecessary wrapper function do_mmap_pgoff() 2020-08-07 11:33:27 -07:00
kernel kasan: don't tag stacks allocated with pagealloc 2020-08-07 11:33:28 -07:00
lib kasan: adjust kasan_stack_oob for tag-based mode 2020-08-07 11:33:28 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/page_alloc: silence a KASAN false positive 2020-08-07 11:33:29 -07:00
net mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
scripts kasan: allow enabling stack tagging for tag-based mode 2020-08-07 11:33:28 -07:00
security mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
sound sound updates for 5.9 2020-08-06 14:27:31 -07:00
tools selftests: add mincore() tests 2020-08-07 11:33:27 -07:00
usr usr: Add support for zstd compressed initramfs 2020-07-31 11:49:08 +02:00
virt s390: implement diag318 2020-08-06 12:59:31 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap It's been a busy cycle for documentation - hopefully the busiest for a 2020-08-04 22:47:54 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS TTY/Serial patches for 5.9-rc1 2020-08-06 14:56:11 -07:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.