When writing tests, it'd often be very useful to be able to intercept
calls to a function in the code being tested and replace it with a
test-specific stub. This has always been an obviously missing piece of
KUnit, and the solutions always involve some tradeoffs with cleanliness,
performance, or impact on non-test code. See the folowing document for
some of the challenges:
https://kunit.dev/mocking.html
This series introduces a new "static_stub" feature add support for this
sort of redirection to KUnit tests.
Any function which might want to be intercepted adds a
call to a macro which checks if a test has redirected calls to it, and
calls the corresponding replacement.
Note that at alternate implementation (based on ftrace) was also
proposed in an earlier RFC:
https://lore.kernel.org/linux-kselftest/20220910212804.670622-3-davidgow@go…
This series only implements "static" stubbing, as it is more compatible
across different architectures, and more flexible w/r/t inlined code,
but we don't rule out offering the ftrace-based solution as well if the
demand is there in the future.
This feature was presented at LPC 2022, see:
- https://lpc.events/event/16/contributions/1308/
- https://www.youtube.com/watch?v=0Nm06EdXWsE
The KUnit 'example' test suite now includes an example of static stubs
being used, and the new 'Function Redirection' API documentation
provides a step-by-step walkthrough for using the new feature.
In addition, an (in-progress) test for the atkbd driver, which provides
an example of static stubs being used, can be found here:
https://kunit-review.googlesource.com/c/linux/+/5631
Cheers,
-- David
---
David Gow (1):
kunit: Expose 'static stub' API to redirect functions
Sadiya Kazi (1):
Documentation: Add Function Redirection API docs
.../kunit/api/functionredirection.rst | 162 ++++++++++++++++++
Documentation/dev-tools/kunit/api/index.rst | 13 +-
include/kunit/static_stub.h | 117 +++++++++++++
lib/kunit/Makefile | 1 +
lib/kunit/kunit-example-test.c | 38 ++++
lib/kunit/static_stub.c | 123 +++++++++++++
6 files changed, 451 insertions(+), 3 deletions(-)
create mode 100644 Documentation/dev-tools/kunit/api/functionredirection.rst
create mode 100644 include/kunit/static_stub.h
create mode 100644 lib/kunit/static_stub.c
--
2.39.0.rc0.267.gcb52ba06e7-goog
Changes from RFC v2
(https://lore.kernel.org/damon/20221130200937.118005-1-sj@kernel.org/)
- Rebased on latest mm-unstable
----
DAMOS let users do system operations in a data access pattern oriented
way. The data access pattern, which is extracted by DAMON, is somewhat
accurate more than what user space could know in many cases. However,
in some situation, users could know something more than the kernel about
the pattern or some special requirements for some types of memory or
processes. For example, some users would have slow swap devices and
knows latency-ciritical processes and therefore want to use DAMON-based
proactive reclamation (DAMON_RECLAIM) for only non-anonymous pages of
non-latency-critical processes.
For such restriction, users could exclude the memory regions from the
initial monitoring regions and use non-dynamic monitoring regions update
monitoring operations set including fvaddr and paddr. They could also
adjust the DAMOS target access pattern. For dynamically changing memory
layout and access pattern, those would be not enough.
To help the case, add an interface, namely DAMOS filters, which can be
used to avoid the DAMOS actions be applied to specific types of memory,
to DAMON kernel API (damon.h). At the moment, it supports filtering
anonymous pages and/or specific memory cgroups in or out for each DAMOS
scheme.
This patchset adds the support for all DAMOS actions that 'paddr'
monitoring operations set supports ('pageout', 'lru_prio', and
'lru_deprio'), and the functionality is exposed via DAMON kernel API
(damon.h) the DAMON sysfs interface (/sys/kernel/mm/damon/admins/), and
DAMON_RECLAIM module parameters.
Patches Sequence
----------------
First patch implements DAMOS filter interface to DAMON kernel API.
Second patch makes the physical address space monitoring operations set
to support the filters from all supporting DAMOS actions. Third patch
adds anonymous pages filter support to DAMON_RECLAIM, and the fourth
patch documents the DAMON_RECLAIM's new feature. Fifth to seventh
patches implement DAMON sysfs files for support of the filters, and
eighth patch connects the file to use DAMOS filters feature. Ninth
patch adds simple self test cases for DAMOS filters of the sysfs
interface. Finally, following two patches (tenth and eleventh) document
the new features and interfaces.
Patchset History
----------------
Changes from RFC v2
(https://lore.kernel.org/damon/20221130200937.118005-1-sj@kernel.org/)
- Rebased on latest mm-unstable
Changes from RFC v1
(https://lore.kernel.org/damon/20221124212114.136863-1-sj@kernel.org/)
- sysfs: Clean up filters directory from scheme directory cleanup path
- sysfs: Link newly created filter to the scheme
- sysfs: Ignore removed memcg when checking path
- sysfs: Guard 'struct mem_cgroup' access with CONFIG_MEMCG
(kernel test robot)
SeongJae Park (11):
mm/damon/core: implement damos filter
mm/damon/paddr: support DAMOS filters
mm/damon/reclaim: add a parameter called skip_anon for avoiding
anonymous pages reclamation
Docs/admin-guide/damon/reclaim: document 'skip_anon' parameter
mm/damon/sysfs-schemes: implement filters directory
mm/damon/sysfs-schemes: implement filter directory
mm/damon/sysfs-schemes: connect filter directory and filters directory
mm/damon/sysfs-schemes: implement scheme filters
selftests/damon/sysfs: test filters directory
Docs/admin-guide/mm/damon/usage: document DAMOS filters of sysfs
Docs/ABI/damon: document scheme filters files
.../ABI/testing/sysfs-kernel-mm-damon | 29 ++
.../admin-guide/mm/damon/reclaim.rst | 9 +
Documentation/admin-guide/mm/damon/usage.rst | 48 ++-
include/linux/damon.h | 51 +++
mm/damon/core.c | 39 ++
mm/damon/paddr.c | 71 +++-
mm/damon/reclaim.c | 19 +
mm/damon/sysfs-schemes.c | 370 +++++++++++++++++-
tools/testing/selftests/damon/sysfs.sh | 29 ++
9 files changed, 652 insertions(+), 13 deletions(-)
--
2.25.1
From: Jeff Xu <jeffxu(a)google.com>
Since Linux introduced the memfd feature, memfd have always had their
execute bit set, and the memfd_create() syscall doesn't allow setting
it differently.
However, in a secure by default system, such as ChromeOS, (where all
executables should come from the rootfs, which is protected by Verified
boot), this executable nature of memfd opens a door for NoExec bypass
and enables “confused deputy attack”. E.g, in VRP bug [1]: cros_vm
process created a memfd to share the content with an external process,
however the memfd is overwritten and used for executing arbitrary code
and root escalation. [2] lists more VRP in this kind.
On the other hand, executable memfd has its legit use, runc uses memfd’s
seal and executable feature to copy the contents of the binary then
execute them, for such system, we need a solution to differentiate runc's
use of executable memfds and an attacker's [3].
To address those above, this set of patches add following:
1> Let memfd_create() set X bit at creation time.
2> Let memfd to be sealed for modifying X bit.
3> A new pid namespace sysctl: vm.memfd_noexec to control the behavior of
X bit.For example, if a container has vm.memfd_noexec=2, then
memfd_create() without MFD_NOEXEC_SEAL will be rejected.
4> A new security hook in memfd_create(). This make it possible to a new
LSM, which rejects or allows executable memfd based on its security policy.
Change history:
v7:
- patch 2/6: remove #ifdef and MAX_PATH (memfd_test.c).
- patch 3/6: check capability (CAP_SYS_ADMIN) from userns instead of
global ns (pid_sysctl.h). Add a tab (pid_namespace.h).
- patch 5/6: remove #ifdef (memfd_test.c)
- patch 6/6: remove unneeded security_move_mount(security.c).
v6:https://lore.kernel.org/lkml/20221206150233.1963717-1-jeffxu@google.com/
- Address comment and move "#ifdef CONFIG_" from .c file to pid_sysctl.h
v5:https://lore.kernel.org/lkml/20221206152358.1966099-1-jeffxu@google.com/
- Pass vm.memfd_noexec from current ns to child ns.
- Fix build issue detected by kernel test robot.
- Add missing security.c
v3:https://lore.kernel.org/lkml/20221202013404.163143-1-jeffxu@google.com/
- Address API design comments in v2.
- Let memfd_create() to set X bit at creation time.
- A new pid namespace sysctl: vm.memfd_noexec to control behavior of X bit.
- A new security hook in memfd_create().
v2:https://lore.kernel.org/lkml/20220805222126.142525-1-jeffxu@google.com/
- address comments in V1.
- add sysctl (vm.mfd_noexec) to set the default file permissions of
memfd_create to be non-executable.
v1:https://lwn.net/Articles/890096/
[1] https://crbug.com/1305411
[2] https://bugs.chromium.org/p/chromium/issues/list?q=type%3Dbug-security%20me…
[3] https://lwn.net/Articles/781013/
Daniel Verkamp (2):
mm/memfd: add F_SEAL_EXEC
selftests/memfd: add tests for F_SEAL_EXEC
Jeff Xu (4):
mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC
mm/memfd: Add write seals when apply SEAL_EXEC to executable memfd
selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC
mm/memfd: security hook for memfd_create
include/linux/lsm_hook_defs.h | 1 +
include/linux/lsm_hooks.h | 4 +
include/linux/pid_namespace.h | 19 ++
include/linux/security.h | 6 +
include/uapi/linux/fcntl.h | 1 +
include/uapi/linux/memfd.h | 4 +
kernel/pid_namespace.c | 5 +
kernel/pid_sysctl.h | 59 ++++
mm/memfd.c | 61 +++-
mm/shmem.c | 6 +
security/security.c | 5 +
tools/testing/selftests/memfd/fuse_test.c | 1 +
tools/testing/selftests/memfd/memfd_test.c | 341 ++++++++++++++++++++-
13 files changed, 510 insertions(+), 3 deletions(-)
create mode 100644 kernel/pid_sysctl.h
base-commit: eb7081409f94a9a8608593d0fb63a1aa3d6f95d8
--
2.39.0.rc1.256.g54fd8350bd-goog
Hello,
The aim of this patch series is to improve the resctrl selftest.
Without these fixes, some unnecessary processing will be executed
and test results will be confusing.
There is no behavior change in test themselves.
[patch 1] Make write_schemata() run to set up shemata with 100% allocation
on first run in MBM test.
[patch 2] The MBA test result message is always output as "ok",
make output message to be "not ok" if MBA check result is failed.
[patch 3] When a child process is created by fork(), the buffer of the
parent process is also copied. Flush the buffer before
executing fork().
[patch 4] Add a signal handler to cleanup properly before exiting the
parent process if there is an error occurs after creating
a child process with fork() in the CAT test.
[patch 5] Before exiting each test CMT/CAT/MBM/MBA, clear test result
files function cat/cmt/mbm/mba_test_cleanup() are called
twice. Delete once.
This patch series is based on Linux v6.1-rc5
Difference from v3:
[patch 2]
Rename "failed" to "ret" to avoid confusion.
[patch 4]
- Use sigaction(2) instead of signal().
- Add a description of using global bm_pid in commit message.
- Add comments to clarify why let the child continue to its
infinite loop after the write() failed.
[patch 5]
Ensure to run cat/cmt/mbm/mba_test_cleanup() to clear test result
file before return if an error occurs.
Pervious versions of this series:
[v1] https://lore.kernel.org/lkml/20220914015147.3071025-1-tan.shaopeng@jp.fujit…
[v2] https://lore.kernel.org/lkml/20221005013933.1486054-1-tan.shaopeng@jp.fujit…
[v3] https://lore.kernel.org/lkml/20221101094341.3383073-1-tan.shaopeng@jp.fujit…
Shaopeng Tan (5):
selftests/resctrl: Fix set up schemata with 100% allocation on first
run in MBM test
selftests/resctrl: Return MBA check result and make it to output
message
selftests/resctrl: Flush stdout file buffer before executing fork()
selftests/resctrl: Cleanup properly when an error occurs in CAT test
selftests/resctrl: Remove duplicate codes that clear each test result
file
tools/testing/selftests/resctrl/cat_test.c | 31 +++++++++++++------
tools/testing/selftests/resctrl/cmt_test.c | 7 ++---
tools/testing/selftests/resctrl/mba_test.c | 23 +++++++-------
tools/testing/selftests/resctrl/mbm_test.c | 20 ++++++------
.../testing/selftests/resctrl/resctrl_tests.c | 4 ---
tools/testing/selftests/resctrl/resctrl_val.c | 1 +
tools/testing/selftests/resctrl/resctrlfs.c | 5 ++-
7 files changed, 50 insertions(+), 41 deletions(-)
--
2.27.0
Dzień dobry,
zapoznałem się z Państwa ofertą i z przyjemnością przyznaję, że przyciąga uwagę i zachęca do dalszych rozmów.
Pomyślałem, że może mógłbym mieć swój wkład w Państwa rozwój i pomóc dotrzeć z tą ofertą do większego grona odbiorców. Pozycjonuję strony www, dzięki czemu generują świetny ruch w sieci.
Możemy porozmawiać w najbliższym czasie?
Pozdrawiam
Adam Charachuta
Changes in v6:
- Updated the interface and made cosmetic changes
Original Cover Letter in v5:
Hello,
This patch series implements IOCTL on the pagemap procfs file to get the
information about the page table entries (PTEs). The following operations
are supported in this ioctl:
- Get the information if the pages are soft-dirty, file mapped, present
or swapped.
- Clear the soft-dirty PTE bit of the pages.
- Get and clear the soft-dirty PTE bit of the pages atomically.
Soft-dirty PTE bit of the memory pages can be read by using the pagemap
procfs file. The soft-dirty PTE bit for the whole memory range of the
process can be cleared by writing to the clear_refs file. There are other
methods to mimic this information entirely in userspace with poor
performance:
- The mprotect syscall and SIGSEGV handler for bookkeeping
- The userfaultfd syscall with the handler for bookkeeping
Some benchmarks can be seen here[1]. This series adds features that weren't
present earlier:
- There is no atomic get soft-dirty PTE bit status and clear operation
possible.
- The soft-dirty PTE bit of only a part of memory cannot be cleared.
Historically, soft-dirty PTE bit tracking has been used in the CRIU
project. The procfs interface is enough for finding the soft-dirty bit
status and clearing the soft-dirty bit of all the pages of a process.
We have the use case where we need to track the soft-dirty PTE bit for
only specific pages on demand. We need this tracking and clear mechanism
of a region of memory while the process is running to emulate the
getWriteWatch() syscall of Windows. This syscall is used by games to
keep track of dirty pages to process only the dirty pages.
The information related to pages if the page is file mapped, present and
swapped is required for the CRIU project[2][3]. The addition of the
required mask, any mask, excluded mask and return masks are also required
for the CRIU project[2].
The IOCTL returns the addresses of the pages which match the specific masks.
The page addresses are returned in struct page_region in a compact form.
The max_pages is needed to support a use case where user only wants to get
a specific number of pages. So there is no need to find all the pages of
interest in the range when max_pages is specified. The IOCTL returns when
the maximum number of the pages are found. The max_pages is optional. If
max_pages is specified, it must be equal or greater than the vec_size.
This restriction is needed to handle worse case when one page_region only
contains info of one page and it cannot be compacted. This is needed to
emulate the Windows getWriteWatch() syscall.
Some non-dirty pages get marked as dirty because of the kernel's
internal activity (such as VMA merging as soft-dirty bit difference isn't
considered while deciding to merge VMAs). The dirty bit of the pages is
stored in the VMA flags and in the per page flags. If any of these two bits
are set, the page is considered to be soft dirty. Suppose you have cleared
the soft dirty bit of half of VMA which will be done by splitting the VMA
and clearing soft dirty bit flag in the half VMA and the pages in it. Now
kernel may decide to merge the VMAs again. So the half VMA becomes dirty
again. This splitting/merging costs performance. The application receives
a lot of pages which aren't dirty in reality but marked as dirty.
Performance is lost again here. Also sometimes user doesn't want the newly
allocated memory to be marked as dirty. PAGEMAP_NO_REUSED_REGIONS flag
solves both the problems. It is used to not depend on the soft dirty flag
in the VMA flags. So VMA splitting and merging doesn't happen. It only
depends on the soft dirty bit of the individual pages. Thus by using this
flag, there may be a scenerio such that the new memory regions which are
just created, doesn't look dirty when seen with the IOCTL, but look dirty
when seen from procfs. This seems okay as the user of this flag know the
implication of using it.
[1] https://lore.kernel.org/lkml/54d4c322-cd6e-eefd-b161-2af2b56aae24@collabora…
[2] https://lore.kernel.org/all/YyiDg79flhWoMDZB@gmail.com/
[3] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com/
Regards,
Muhammad Usama Anjum
Muhammad Usama Anjum (3):
fs/proc/task_mmu: update functions to clear the soft-dirty PTE bit
fs/proc/task_mmu: Implement IOCTL to get and/or the clear info about PTEs
selftests: vm: add pagemap ioctl tests
fs/proc/task_mmu.c | 410 +++++++++++-
include/uapi/linux/fs.h | 56 ++
tools/include/uapi/linux/fs.h | 56 ++
tools/testing/selftests/vm/.gitignore | 1 +
tools/testing/selftests/vm/Makefile | 5 +-
tools/testing/selftests/vm/pagemap_ioctl.c | 698 +++++++++++++++++++++
6 files changed, 1193 insertions(+), 33 deletions(-)
create mode 100644 tools/testing/selftests/vm/pagemap_ioctl.c
--
2.30.2