mm: rename GENERIC_PTDUMP and PTDUMP_CORE

Platforms subscribe into generic ptdump implementation via GENERIC_PTDUMP.
But generic ptdump gets enabled via PTDUMP_CORE. These configs
combination is co

mm: rename GENERIC_PTDUMP and PTDUMP_CORE

Platforms subscribe into generic ptdump implementation via GENERIC_PTDUMP.
But generic ptdump gets enabled via PTDUMP_CORE. These configs
combination is confusing as they sound very similar and does not
differentiate between platform's feature subscription and feature
enablement for ptdump. Rename the configs as ARCH_HAS_PTDUMP and PTDUMP
making it more clear and improve readability.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
Reviewed-by: Christophe Leroy <[email protected]> (powerpc)
Acked-by: Catalin Marinas <[email protected]> [arm64]
Cc: Will Deacon <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Steven Price <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: make DEBUG_WX depdendent on GENERIC_PTDUMP

DEBUG_WX selects PTDUMP_CORE without even ensuring that the given platform
implements GENERIC_PTDUMP. This problem has been latent until now, as all
t

mm: make DEBUG_WX depdendent on GENERIC_PTDUMP

DEBUG_WX selects PTDUMP_CORE without even ensuring that the given platform
implements GENERIC_PTDUMP. This problem has been latent until now, as all
the platforms subscribing ARCH_HAS_DEBUG_WX also subscribe GENERIC_PTDUMP.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
Reviewed-by: Steven Price <[email protected]>
Reviewed-by: Christophe Leroy <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

slub: Introduce CONFIG_SLUB_RCU_DEBUG

Currently, KASAN is unable to catch use-after-free in SLAB_TYPESAFE_BY_RCU
slabs because use-after-free is allowed within the RCU grace period by
design.

Add a

slub: Introduce CONFIG_SLUB_RCU_DEBUG

Currently, KASAN is unable to catch use-after-free in SLAB_TYPESAFE_BY_RCU
slabs because use-after-free is allowed within the RCU grace period by
design.

Add a SLUB debugging feature which RCU-delays every individual
kmem_cache_free() before either actually freeing the object or handing it
off to KASAN, and change KASAN to poison freed objects as normal when this
option is enabled.

For now I've configured Kconfig.debug to default-enable this feature in the
KASAN GENERIC and SW_TAGS modes; I'm not enabling it by default in HW_TAGS
mode because I'm not sure if it might have unwanted performance degradation
effects there.

Note that this is mostly useful with KASAN in the quarantine-based GENERIC
mode; SLAB_TYPESAFE_BY_RCU slabs are basically always also slabs with a
->ctor, and KASAN's assign_tag() currently has to assign fixed tags for
those, reducing the effectiveness of SW_TAGS/HW_TAGS mode.
(A possible future extension of this work would be to also let SLUB call
the ->ctor() on every allocation instead of only when the slab page is
allocated; then tag-based modes would be able to assign new tags on every
reallocation.)

Tested-by: [email protected]
Reviewed-by: Andrey Konovalov <[email protected]>
Acked-by: Marco Elver <[email protected]>
Acked-by: Vlastimil Babka <[email protected]> #slab
Signed-off-by: Jann Horn <[email protected]>
Signed-off-by: Vlastimil Babka <[email protected]>

show more ...

mm/slub: unify all sl[au]b parameters with "slab_$param"

Since the SLAB allocator has been removed, so we can clean up the
sl[au]b_$params. With only one slab allocator left, it's better to use the

mm/slub: unify all sl[au]b parameters with "slab_$param"

Since the SLAB allocator has been removed, so we can clean up the
sl[au]b_$params. With only one slab allocator left, it's better to use the
generic "slab" term instead of "slub" which is an implementation detail,
which is pointed out by Vlastimil Babka. For more information please see
[1]. Hence, we are going to use "slab_$param" as the primary prefix.

This patch is changing the following slab parameters
- slub_max_order
- slub_min_order
- slub_min_objects
- slub_debug
to
- slab_max_order
- slab_min_order
- slab_min_objects
- slab_debug
as the primary slab parameters for all references of them in docs and
comments. But this patch won't change variables and functions inside
slub as we will have wider slub/slab change.

Meanwhile, "slub_$params" can also be passed by command line, which is
to keep backward compatibility. Also mark all "slub_$params" as legacy.

Remove the separate descriptions for slub_[no]merge, append legacy tip
for them at the end of descriptions of slab_[no]merge.

[1] https://lore.kernel.org/linux-mm/[email protected]/

Signed-off-by: Xiongwei Song <[email protected]>
Reviewed-by: Vlastimil Babka <[email protected]>
Signed-off-by: Vlastimil Babka <[email protected]>

show more ...

mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile

Remove CONFIG_SLAB, CONFIG_DEBUG_SLAB, CONFIG_SLAB_DEPRECATED and
everything in Kconfig files and mm/Makefile that depends on those. Since
S

mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile

Remove CONFIG_SLAB, CONFIG_DEBUG_SLAB, CONFIG_SLAB_DEPRECATED and
everything in Kconfig files and mm/Makefile that depends on those. Since
SLUB is the only remaining allocator, remove the allocator choice, make
CONFIG_SLUB a "def_bool y" for now and remove all explicit dependencies
on SLUB or SLAB as it's now always enabled. Make every option's verbose
name and description refer to "the slab allocator" without refering to
the specific implementation. Do not rename the CONFIG_ option names yet.

Everything under #ifdef CONFIG_SLAB, and mm/slab.c is now dead code, all
code under #ifdef CONFIG_SLUB is now always compiled.

Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Christoph Lameter <[email protected]>
Acked-by: David Rientjes <[email protected]>
Tested-by: David Rientjes <[email protected]>
Reviewed-by: Hyeonggon Yoo <[email protected]>
Tested-by: Hyeonggon Yoo <[email protected]>
Signed-off-by: Vlastimil Babka <[email protected]>

show more ...

mm: page_table_check: Make it dependent on EXCLUSIVE_SYSTEM_RAM

Without EXCLUSIVE_SYSTEM_RAM, users are allowed to map arbitrary
physical memory regions into the userspace via /dev/mem. At the same

mm: page_table_check: Make it dependent on EXCLUSIVE_SYSTEM_RAM

Without EXCLUSIVE_SYSTEM_RAM, users are allowed to map arbitrary
physical memory regions into the userspace via /dev/mem. At the same
time, pages may change their properties (e.g., from anonymous pages to
named pages) while they are still being mapped in the userspace, leading
to "corruption" detected by the page table check.

To avoid these false positives, this patch makes PAGE_TABLE_CHECK
depends on EXCLUSIVE_SYSTEM_RAM. This dependency is understandable
because PAGE_TABLE_CHECK is a hardening technique but /dev/mem without
STRICT_DEVMEM (i.e., !EXCLUSIVE_SYSTEM_RAM) is itself a security
problem.

Even with EXCLUSIVE_SYSTEM_RAM, I/O pages may be still allowed to be
mapped via /dev/mem. However, these pages are always considered as named
pages, so they won't break the logic used in the page table check.

Cc: <[email protected]> # 5.17
Signed-off-by: Ruihan Li <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Acked-by: Pasha Tatashin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

mm: change per-VMA lock statistics to be disabled by default

Change CONFIG_PER_VMA_LOCK_STATS to be disabled by default, as most users
don't need it. Add configuration help to clarify its usage.

L

mm: change per-VMA lock statistics to be disabled by default

Change CONFIG_PER_VMA_LOCK_STATS to be disabled by default, as most users
don't need it. Add configuration help to clarify its usage.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 52f238653e45 ("mm: introduce per-VMA lock statistics")
Signed-off-by: Suren Baghdasaryan <[email protected]>
Suggested-by: Linus Torvalds <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

kmemleak-test: fix kmemleak_test.c build logic

kmemleak-test.c was moved to the samples directory in 1abbef4f51724
("mm,kmemleak-test.c: move kmemleak-test.c to samples dir").

If CONFIG_DEBUG_KMEML

kmemleak-test: fix kmemleak_test.c build logic

kmemleak-test.c was moved to the samples directory in 1abbef4f51724
("mm,kmemleak-test.c: move kmemleak-test.c to samples dir").

If CONFIG_DEBUG_KMEMLEAK_TEST=m and CONFIG_SAMPLES is unset,
kmemleak-test.c will be unnecessarily compiled.

So move the entry for CONFIG_DEBUG_KMEMLEAK_TEST from mm/Kconfig and add a
new CONFIG_SAMPLE_KMEMLEAK in samples/ to control whether kmemleak-test.c
is built or not.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 1abbef4f51724 ("mm,kmemleak-test.c: move kmemleak-test.c to samples dir")
Signed-off-by: Hao Ge <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Alex Gaynor <[email protected]>
Cc: Alex Williamson <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Finn Behrens <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: Tony Krowiak <[email protected]>
Cc: Ye Xingchen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: introduce per-VMA lock statistics

Add a new CONFIG_PER_VMA_LOCK_STATS config option to dump extra statistics
about handling page fault under VMA lock.

Link: https://lkml.kernel.org/r/2023022717

mm: introduce per-VMA lock statistics

Add a new CONFIG_PER_VMA_LOCK_STATS config option to dump extra statistics
about handling page fault under VMA lock.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Suren Baghdasaryan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm/slub: fix help comment of SLUB_DEBUG

Since commit ab4d5ed5eeda ("slub: Enable sysfs support for
!CONFIG_SLUB_DEBUG"), disabling SLUB_DEBUG no longer disables sysfs
support completely, so fix the

mm/slub: fix help comment of SLUB_DEBUG

Since commit ab4d5ed5eeda ("slub: Enable sysfs support for
!CONFIG_SLUB_DEBUG"), disabling SLUB_DEBUG no longer disables sysfs
support completely, so fix the description. Also update the path to
/sys/kernel/slab.

Signed-off-by: Vernon Yang <[email protected]>
Signed-off-by: Vlastimil Babka <[email protected]>

show more ...

mm: move KMEMLEAK's Kconfig items from lib to mm

Have the kmemleak's source code and Kconfig items be in the same directory.

Link: https://lkml.kernel.org/r/1674091345-14799-1-git-send-email-zhaoya

mm: move KMEMLEAK's Kconfig items from lib to mm

Have the kmemleak's source code and Kconfig items be in the same directory.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Zhaoyang Huang <[email protected]>
Acked-by: Mike Rapoport (IBM) <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: ke.wang <[email protected]>
Cc: Mirsad Goran Todorovac <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Cc: Catalin Marinas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

tools/vm: rename tools/vm to tools/mm

Rename tools/vm to tools/mm for being more consistent with the code and
documentation directories, and won't be confused with virtual machines.

Link: https://l

tools/vm: rename tools/vm to tools/mm

Rename tools/vm to tools/mm for being more consistent with the code and
documentation directories, and won't be confused with virtual machines.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: SeongJae Park <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm, slub: add CONFIG_SLUB_TINY

For tiny systems that have used SLOB until now, SLUB might be
impractical due to its higher memory usage. To help with that, introduce
an option CONFIG_SLUB_TINY that

mm, slub: add CONFIG_SLUB_TINY

For tiny systems that have used SLOB until now, SLUB might be
impractical due to its higher memory usage. To help with that, introduce
an option CONFIG_SLUB_TINY that modifies SLUB to use less memory.
This is done by sacrificing scalability, security and debugging
features, therefore not recommended for any system with more than 16MB
RAM.

This commit introduces the option and uses it to set other related
options in a way that reduces memory usage.

Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Hyeonggon Yoo <[email protected]>
Acked-by: Mike Rapoport <[email protected]>
Reviewed-by: Christoph Lameter <[email protected]>

show more ...

mm: Kconfig: reorganize misplaced mm options

After commits 7b42f1041c98 ("mm: Kconfig: move swap and slab config
options to the MM section") and 519bcb797907 ("mm: Kconfig: group swap,
slab, hotplug

mm: Kconfig: reorganize misplaced mm options

After commits 7b42f1041c98 ("mm: Kconfig: move swap and slab config
options to the MM section") and 519bcb797907 ("mm: Kconfig: group swap,
slab, hotplug and thp options into submenus") we now have nicely organized
mm related config options. I have noticed some that were still misplaced,
so this moves them from various places into the new structure:

VM_EVENT_COUNTERS, COMPAT_BRK, MMAP_ALLOW_UNINITIALIZED to mm/Kconfig and
general MM section.

SLUB_STATS to mm/Kconfig and the slab submenu.

DEBUG_SLAB, SLUB_DEBUG, SLUB_DEBUG_ON to mm/Kconfig.debug and the Kernel
hacking / Memory Debugging submenu.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: page table check

Check user page table entries at the time they are added and removed.

Allows to synchronously catch memory corruption issues related to double
mapping.

When a pte for an anony

mm: page table check

Check user page table entries at the time they are added and removed.

Allows to synchronously catch memory corruption issues related to double
mapping.

When a pte for an anonymous page is added into page table, we verify
that this pte does not already point to a file backed page, and vice
versa if this is a file backed page that is being added we verify that
this page does not have an anonymous mapping

We also enforce that read-only sharing for anonymous pages is allowed
(i.e. cow after fork). All other sharing must be for file pages.

Page table check allows to protect and debug cases where "struct page"
metadata became corrupted for some reason. For example, when refcnt or
mapcount become invalid.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Pasha Tatashin <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Greg Thelen <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sami Tolvanen <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Wei Xu <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

mm, page_poison: remove CONFIG_PAGE_POISONING_ZERO

CONFIG_PAGE_POISONING_ZERO uses the zero pattern instead of 0xAA. It was
introduced by commit 1414c7f4f7d7 ("mm/page_poisoning.c: allow for zero
p

mm, page_poison: remove CONFIG_PAGE_POISONING_ZERO

CONFIG_PAGE_POISONING_ZERO uses the zero pattern instead of 0xAA. It was
introduced by commit 1414c7f4f7d7 ("mm/page_poisoning.c: allow for zero
poisoning"), noting that using zeroes retains the benefit of sanitizing
content of freed pages, with the benefit of not having to zero them again
on alloc, and the downside of making some forms of corruption (stray
writes of NULLs) harder to detect than with the 0xAA pattern. Together
with CONFIG_PAGE_POISONING_NO_SANITY it made possible to sanitize the
contents on free without checking it back on alloc.

These days we have the init_on_free() option to achieve sanitization with
zeroes and to save clearing on alloc (and without checking on alloc).
Arguably if someone does choose to check the poison for corruption on
alloc, the savings of not clearing the page are secondary, and it makes
sense to always use the 0xAA poison pattern. Thus, remove the
CONFIG_PAGE_POISONING_ZERO option for being redundant.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Mateusz Nosek <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

mm, page_poison: remove CONFIG_PAGE_POISONING_NO_SANITY

CONFIG_PAGE_POISONING_NO_SANITY skips the check on page alloc whether the
poison pattern was corrupted, suggesting a use-after-free. The moti

mm, page_poison: remove CONFIG_PAGE_POISONING_NO_SANITY

CONFIG_PAGE_POISONING_NO_SANITY skips the check on page alloc whether the
poison pattern was corrupted, suggesting a use-after-free. The motivation
to introduce it in commit 8823b1dbc05f ("mm/page_poison.c: enable
PAGE_POISONING as a separate option") was to simply sanitize freed pages,
optimally together with CONFIG_PAGE_POISONING_ZERO.

These days we have an init_on_free=1 boot option, which makes this use
case of page poisoning redundant. For sanitizing, writing zeroes is
sufficient, there is pretty much no benefit from writing the 0xAA poison
pattern to freed pages, without checking it back on alloc. Thus, remove
this option and suggest init_on_free instead in the main config's help.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Mateusz Nosek <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

kernel/power: allow hibernation with page_poison sanity checking

Page poisoning used to be incompatible with hibernation, as the state of
poisoned pages was lost after resume, thus enabling CONFIG_H

kernel/power: allow hibernation with page_poison sanity checking

Page poisoning used to be incompatible with hibernation, as the state of
poisoned pages was lost after resume, thus enabling CONFIG_HIBERNATION
forces CONFIG_PAGE_POISONING_NO_SANITY. For the same reason, the
poisoning with zeroes variant CONFIG_PAGE_POISONING_ZERO used to disable
hibernation. The latter restriction was removed by commit 1ad1410f632d
("PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO") and
similarly for init_on_free by commit 18451f9f9e58 ("PM: hibernate: fix
crashes with init_on_free=1") by making sure free pages are cleared after
resume.

We can use the same mechanism to instead poison free pages with
PAGE_POISON after resume. This covers both zero and 0xAA patterns. Thus
we can remove the Kconfig restriction that disables page poison sanity
checking when hibernation is enabled.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]> [hibernation]
Reviewed-by: David Hildenbrand <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Mateusz Nosek <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasi

treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <[email protected]>

show more ...

mm: add DEBUG_WX support

Patch series "Extract DEBUG_WX to shared use".

Some architectures support DEBUG_WX function, it's verbatim from each
others, so extract to mm/Kconfig.debug for shared use.

mm: add DEBUG_WX support

Patch series "Extract DEBUG_WX to shared use".

Some architectures support DEBUG_WX function, it's verbatim from each
others, so extract to mm/Kconfig.debug for shared use.

PPC and ARM ports don't support generic page dumper yet, so we only
refine x86 and arm64 port in this patch series.

For RISC-V port, the DEBUG_WX support depends on other patches which
be merged already:
- RISC-V page table dumper
- Support strict kernel memory permissions for security

This patch (of 4):

Some architectures support DEBUG_WX function, it's verbatim from each
others. Extract to mm/Kconfig.debug for shared use.

[[email protected]: reword text, per Will Deacon & Zong Li]
Link: http://lkml.kernel.org/r/20200427194245.oxRJKj3fn%[email protected]
[[email protected]: remove the specific name of arm64]
Link: http://lkml.kernel.org/r/3a6a92ecedc54e1d0fc941398e63d504c2cd5611.1589178399.git.zong.li@sifive.com
[[email protected]: add MMU dependency for DEBUG_WX]
Link: http://lkml.kernel.org/r/4a674ac7863ff39ca91847b10e51209771f99416.1589178399.git.zong.li@sifive.com
Suggested-by: Palmer Dabbelt <[email protected]>
Signed-off-by: Zong Li <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/23980cd0f0e5d79e24a92169116407c75bcc650d.1587455584.git.zong.li@sifive.com
Signed-off-by: Linus Torvalds <[email protected]>

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mm: add generic ptdump

Add a generic version of page table dumping that architectures can opt-in
to.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Steve

mm: add generic ptdump

Add a generic version of page table dumping that architectures can opt-in
to.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Steven Price <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Hogan <[email protected]>
Cc: James Morse <[email protected]>
Cc: Jerome Glisse <[email protected]>
Cc: "Liang, Kan" <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Zong Li <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm, page_owner, debug_pagealloc: save and dump freeing stack trace

The debug_pagealloc functionality is useful to catch buggy page allocator
users that cause e.g. use after free or double free. Wh

mm, page_owner, debug_pagealloc: save and dump freeing stack trace

The debug_pagealloc functionality is useful to catch buggy page allocator
users that cause e.g. use after free or double free. When page
inconsistency is detected, debugging is often simpler by knowing the call
stack of process that last allocated and freed the page. When page_owner
is also enabled, we record the allocation stack trace, but not freeing.

This patch therefore adds recording of freeing process stack trace to page
owner info, if both page_owner and debug_pagealloc are configured and
enabled. With only page_owner enabled, this info is not useful for the
memory leak debugging use case. dump_page() is adjusted to print the
info. An example result of calling __free_pages() twice may look like
this (note the page last free stack trace):

BUG: Bad page state in process bash pfn:13d8f8
page:ffffc31984f63e00 refcount:-1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x1affff800000000()
raw: 01affff800000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 ffffffffffffffff 0000000000000000
page dumped because: nonzero _refcount
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xcc0(GFP_KERNEL)
prep_new_page+0x143/0x150
get_page_from_freelist+0x289/0x380
__alloc_pages_nodemask+0x13c/0x2d0
khugepaged+0x6e/0xc10
kthread+0xf9/0x130
ret_from_fork+0x3a/0x50
page last free stack trace:
free_pcp_prepare+0x134/0x1e0
free_unref_page+0x18/0x90
khugepaged+0x7b/0xc10
kthread+0xf9/0x130
ret_from_fork+0x3a/0x50
Modules linked in:
CPU: 3 PID: 271 Comm: bash Not tainted 5.3.0-rc4-2.g07a1a73-default+ #57
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack+0x85/0xc0
bad_page.cold+0xba/0xbf
rmqueue_pcplist.isra.0+0x6c5/0x6d0
rmqueue+0x2d/0x810
get_page_from_freelist+0x191/0x380
__alloc_pages_nodemask+0x13c/0x2d0
__get_free_pages+0xd/0x30
__pud_alloc+0x2c/0x110
copy_page_range+0x4f9/0x630
dup_mmap+0x362/0x480
dup_mm+0x68/0x110
copy_process+0x19e1/0x1b40
_do_fork+0x73/0x310
__x64_sys_clone+0x75/0x80
do_syscall_64+0x6e/0x1e0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f10af854a10
...

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm, debug_pagealloc: use a page type instead of page_ext flag

When debug_pagealloc is enabled, we currently allocate the page_ext
array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now t

mm, debug_pagealloc: use a page type instead of page_ext flag

When debug_pagealloc is enabled, we currently allocate the page_ext
array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that
we have the page_type field in struct page, we can use that instead, as
guard pages are neither PageSlab nor mapped to userspace. This reduces
memory overhead when debug_pagealloc is enabled and there are no other
features requiring the page_ext array.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm, page_alloc: more extensive free page checking with debug_pagealloc

The page allocator checks struct pages for expected state (mapcount,
flags etc) as pages are being allocated (check_new_page())

mm, page_alloc: more extensive free page checking with debug_pagealloc

The page allocator checks struct pages for expected state (mapcount,
flags etc) as pages are being allocated (check_new_page()) and freed
(free_pages_check()) to provide some defense against errors in page
allocator users.

Prior commits 479f854a207c ("mm, page_alloc: defer debugging checks of
pages allocated from the PCP") and 4db7548ccbd9 ("mm, page_alloc: defer
debugging checks of freed pages until a PCP drain") this has happened
for order-0 pages as they were allocated from or freed to the per-cpu
caches (pcplists). Since those are fast paths, the checks are now
performed only when pages are moved between pcplists and global free
lists. This however lowers the chances of catching errors soon enough.

In order to increase the chances of the checks to catch errors, the
kernel has to be rebuilt with CONFIG_DEBUG_VM, which also enables
multiple other internal debug checks (VM_BUG_ON() etc), which is
suboptimal when the goal is to catch errors in mm users, not in mm code
itself.

To catch some wrong users of the page allocator we have
CONFIG_DEBUG_PAGEALLOC, which is designed to have virtually no overhead
unless enabled at boot time. Memory corruptions when writing to freed
pages have often the same underlying errors (use-after-free, double free)
as corrupting the corresponding struct pages, so this existing debugging
functionality is a good fit to extend by also perform struct page checks
at least as often as if CONFIG_DEBUG_VM was enabled.

Specifically, after this patch, when debug_pagealloc is enabled on boot,
and CONFIG_DEBUG_VM disabled, pages are checked when allocated from or
freed to the pcplists *in addition* to being moved between pcplists and
free lists. When both debug_pagealloc and CONFIG_DEBUG_VM are enabled,
pages are checked when being moved between pcplists and free lists *in
addition* to when allocated from or freed to the pcplists.

When debug_pagealloc is not enabled on boot, the overhead in fast paths
should be virtually none thanks to the use of static key.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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