The checksum_32 code was originally written to only handle 2-byte
aligned buffers, but was later extended to support arbitrary alignment.
However, the non-PPro variant doesn't apply the carry before jumping to
the 2- or 4-byte aligned versions, which clear CF.
This causes the new checksum_kunit test to fail, as it runs with a large
number of different possible alignments and both with and without
carries.
For example:
./tools/testing/kunit/kunit.py run --arch i386 --kconfig_add CONFIG_M486=y checksum
Gives:
KTAP version 1
# Subtest: checksum
1..3
ok 1 test_csum_fixed_random_inputs
# test_csum_all_carry_inputs: ASSERTION FAILED at lib/checksum_kunit.c:267
Expected result == expec, but
result == 65281 (0xff01)
expec == 65280 (0xff00)
not ok 2 test_csum_all_carry_inputs
# test_csum_no_carry_inputs: ASSERTION FAILED at lib/checksum_kunit.c:314
Expected result == expec, but
result == 65535 (0xffff)
expec == 65534 (0xfffe)
not ok 3 test_csum_no_carry_inputs
With this patch, it passes.
KTAP version 1
# Subtest: checksum
1..3
ok 1 test_csum_fixed_random_inputs
ok 2 test_csum_all_carry_inputs
ok 3 test_csum_no_carry_inputs
I also tested it on a real 486DX2, with the same results.
Signed-off-by: David Gow <davidgow(a)google.com>
---
This is a follow-up to the UML patch to use the common 32-bit x86
checksum implementations:
https://lore.kernel.org/linux-um/20230704083022.692368-2-davidgow@google.co…
---
arch/x86/lib/checksum_32.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/lib/checksum_32.S b/arch/x86/lib/checksum_32.S
index 23318c338db0..128287cea42d 100644
--- a/arch/x86/lib/checksum_32.S
+++ b/arch/x86/lib/checksum_32.S
@@ -62,6 +62,7 @@ SYM_FUNC_START(csum_partial)
jl 8f
movzbl (%esi), %ebx
adcl %ebx, %eax
+ adcl $0, %eax
roll $8, %eax
inc %esi
testl $2, %esi
--
2.41.0.255.g8b1d071c50-goog
While it probably doesn't make a huge difference given the current KUnit
coverage we will get the best coverage of arm64 architecture features if
we specify -cpu=max rather than picking a specific CPU, this will include
all architecture features that qemu supports including many which have not
yet made it into physical implementations.
Due to performance issues emulating the architected pointer authentication
algorithm it is recommended to use the implementation defined algorithm
that qemu has instead, this should make no meaningful difference to the
coverage and will run the tests faster.
Signed-off-by: Mark Brown <broonie(a)kernel.org>
---
tools/testing/kunit/qemu_configs/arm64.py | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/kunit/qemu_configs/arm64.py b/tools/testing/kunit/qemu_configs/arm64.py
index 67d04064f785..d3ff27024755 100644
--- a/tools/testing/kunit/qemu_configs/arm64.py
+++ b/tools/testing/kunit/qemu_configs/arm64.py
@@ -9,4 +9,4 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y''',
qemu_arch='aarch64',
kernel_path='arch/arm64/boot/Image.gz',
kernel_command_line='console=ttyAMA0',
- extra_qemu_params=['-machine', 'virt', '-cpu', 'cortex-a57'])
+ extra_qemu_params=['-machine', 'virt', '-cpu', 'max,pauth-impdef=on'])
---
base-commit: 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5
change-id: 20230702-kunit-arm64-cpu-max-7e3aa5f02fb2
Best regards,
--
Mark Brown <broonie(a)kernel.org>
=== Context ===
In the context of a middlebox, fragmented packets are tricky to handle.
The full 5-tuple of a packet is often only available in the first
fragment which makes enforcing consistent policy difficult. There are
really only two stateless options, neither of which are very nice:
1. Enforce policy on first fragment and accept all subsequent fragments.
This works but may let in certain attacks or allow data exfiltration.
2. Enforce policy on first fragment and drop all subsequent fragments.
This does not really work b/c some protocols may rely on
fragmentation. For example, DNS may rely on oversized UDP packets for
large responses.
So stateful tracking is the only sane option. RFC 8900 [0] calls this
out as well in section 6.3:
Middleboxes [...] should process IP fragments in a manner that is
consistent with [RFC0791] and [RFC8200]. In many cases, middleboxes
must maintain state in order to achieve this goal.
=== BPF related bits ===
Policy has traditionally been enforced from XDP/TC hooks. Both hooks
run before kernel reassembly facilities. However, with the new
BPF_PROG_TYPE_NETFILTER, we can rather easily hook into existing
netfilter reassembly infra.
The basic idea is we bump a refcnt on the netfilter defrag module and
then run the bpf prog after the defrag module runs. This allows bpf
progs to transparently see full, reassembled packets. The nice thing
about this is that progs don't have to carry around logic to detect
fragments.
=== Changelog ===
Changes from v3:
* Correctly initialize `addrlen` stack var for recvmsg()
Changes from v2:
* module_put() if ->enable() fails
* Fix CI build errors
Changes from v1:
* Drop bpf_program__attach_netfilter() patches
* static -> static const where appropriate
* Fix callback assignment order during registration
* Only request_module() if callbacks are missing
* Fix retval when modprobe fails in userspace
* Fix v6 defrag module name (nf_defrag_ipv6_hooks -> nf_defrag_ipv6)
* Simplify priority checking code
* Add warning if module doesn't assign callbacks in the future
* Take refcnt on module while defrag link is active
[0]: https://datatracker.ietf.org/doc/html/rfc8900
Daniel Xu (6):
netfilter: defrag: Add glue hooks for enabling/disabling defrag
netfilter: bpf: Support BPF_F_NETFILTER_IP_DEFRAG in netfilter link
netfilter: bpf: Prevent defrag module unload while link active
bpf: selftests: Support not connecting client socket
bpf: selftests: Support custom type and proto for client sockets
bpf: selftests: Add defrag selftests
include/linux/netfilter.h | 15 +
include/uapi/linux/bpf.h | 5 +
net/ipv4/netfilter/nf_defrag_ipv4.c | 17 +-
net/ipv6/netfilter/nf_defrag_ipv6_hooks.c | 11 +
net/netfilter/core.c | 6 +
net/netfilter/nf_bpf_link.c | 150 +++++++++-
tools/include/uapi/linux/bpf.h | 5 +
tools/testing/selftests/bpf/Makefile | 4 +-
.../selftests/bpf/generate_udp_fragments.py | 90 ++++++
.../selftests/bpf/ip_check_defrag_frags.h | 57 ++++
tools/testing/selftests/bpf/network_helpers.c | 26 +-
tools/testing/selftests/bpf/network_helpers.h | 3 +
.../bpf/prog_tests/ip_check_defrag.c | 283 ++++++++++++++++++
.../selftests/bpf/progs/ip_check_defrag.c | 104 +++++++
14 files changed, 754 insertions(+), 22 deletions(-)
create mode 100755 tools/testing/selftests/bpf/generate_udp_fragments.py
create mode 100644 tools/testing/selftests/bpf/ip_check_defrag_frags.h
create mode 100644 tools/testing/selftests/bpf/prog_tests/ip_check_defrag.c
create mode 100644 tools/testing/selftests/bpf/progs/ip_check_defrag.c
--
2.41.0
The #endif is the wrong side of a } causing a build failure when
__NR_userfaultfd is not defined. Fix this by moving the #end to
enclose the }
Fixes: 9eac40fc0cc7 ("selftests/mm: mkdirty: test behavior of (pte|pmd)_mkdirty on VMAs without write permissions")
Signed-off-by: Colin Ian King <colin.i.king(a)gmail.com>
---
tools/testing/selftests/mm/mkdirty.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/mkdirty.c b/tools/testing/selftests/mm/mkdirty.c
index 6d71d972997b..301abb99e027 100644
--- a/tools/testing/selftests/mm/mkdirty.c
+++ b/tools/testing/selftests/mm/mkdirty.c
@@ -321,8 +321,8 @@ static void test_uffdio_copy(void)
munmap:
munmap(dst, pagesize);
free(src);
-#endif /* __NR_userfaultfd */
}
+#endif /* __NR_userfaultfd */
int main(void)
{
--
2.39.2
Awk is already called for /sys/block/zram#/mm_stat parsing, so use it
to also perform the floating point capacity vs consumption ratio
calculations. The test output is unchanged.
This allows bc to be dropped as a dependency for the zram selftests.
The documented free dependency can also be removed following
d18da7ec37195 ("selftests/zram01.sh: Fix compression ratio calculation")
Signed-off-by: David Disseldorp <ddiss(a)suse.de>
---
tools/testing/selftests/zram/README | 2 --
tools/testing/selftests/zram/zram01.sh | 18 ++++++++----------
2 files changed, 8 insertions(+), 12 deletions(-)
v2: drop unused dependencies from selftests/zram/README
diff --git a/tools/testing/selftests/zram/README b/tools/testing/selftests/zram/README
index 110b34834a6fa..510ca5a1087f5 100644
--- a/tools/testing/selftests/zram/README
+++ b/tools/testing/selftests/zram/README
@@ -27,9 +27,7 @@ zram01.sh: creates general purpose ram disks with ext4 filesystems
zram02.sh: creates block device for swap
Commands required for testing:
- - bc
- dd
- - free
- awk
- mkswap
- swapon
diff --git a/tools/testing/selftests/zram/zram01.sh b/tools/testing/selftests/zram/zram01.sh
index 8f4affe34f3e4..df1b1d4158989 100755
--- a/tools/testing/selftests/zram/zram01.sh
+++ b/tools/testing/selftests/zram/zram01.sh
@@ -33,7 +33,7 @@ zram_algs="lzo"
zram_fill_fs()
{
- for i in $(seq $dev_start $dev_end); do
+ for ((i = $dev_start; i <= $dev_end && !ERR_CODE; i++)); do
echo "fill zram$i..."
local b=0
while [ true ]; do
@@ -44,15 +44,13 @@ zram_fill_fs()
done
echo "zram$i can be filled with '$b' KB"
- local mem_used_total=`awk '{print $3}' "/sys/block/zram$i/mm_stat"`
- local v=$((100 * 1024 * $b / $mem_used_total))
- if [ "$v" -lt 100 ]; then
- echo "FAIL compression ratio: 0.$v:1"
- ERR_CODE=-1
- return
- fi
-
- echo "zram compression ratio: $(echo "scale=2; $v / 100 " | bc):1: OK"
+ awk -v b="$b" '{ v = (100 * 1024 * b / $3) } END {
+ if (v < 100) {
+ printf "FAIL compression ratio: 0.%u:1\n", v
+ exit 1
+ }
+ printf "zram compression ratio: %.2f:1: OK\n", v / 100
+ }' "/sys/block/zram$i/mm_stat" || ERR_CODE=-1
done
}
--
2.35.3
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 v24*:
- Rebase on top of next-20230710
- Place WP markers in case of hole as well
*Changes in v23*:
- Set vec_buf_index in loop only when vec_buf_index is set
- Return -EFAULT instead of -EINVAL if vec is NULL
- Correctly return the walk ending address to the page granularity
*Changes in v22*:
- Interface change:
- Replace [start start + len) with [start, end)
- Return the ending address of the address walk in start
*Changes in v21*:
- Abort walk instead of returning error if WP is to be performed on
partial hugetlb
*Changes in v20*
- Correct PAGE_IS_FILE and add PAGE_IS_PFNZERO
*Changes in v19*
- Minor changes and interface updates
*Changes in v18*
- Rebase on top of next-20230613
- Minor updates
*Changes in v17*
- Rebase on top of next-20230606
- Minor improvements in PAGEMAP_SCAN IOCTL patch
*Changes in v16*
- Fix a corner case
- Add exclusive PM_SCAN_OP_WP back
*Changes in v15*
- Build fix (Add missed build fix in RESEND)
*Changes in v14*
- Fix build error caused by #ifdef added at last minute in some configs
*Changes in v13*
- Rebase on top of next-20230414
- Give-up on using uffd_wp_range() and write new helpers, flush tlb only
once
*Changes in v12*
- Update and other memory types to UFFD_FEATURE_WP_ASYNC
- Rebaase on top of next-20230406
- Review updates
*Changes in v11*
- Rebase on top of next-20230307
- Base patches on UFFD_FEATURE_WP_UNPOPULATED
- Do a lot of cosmetic changes and review updates
- Remove ENGAGE_WP + !GET operation as it can be performed with
UFFDIO_WRITEPROTECT
*Changes in v10*
- Add specific condition to return error if hugetlb is used with wp
async
- Move changes in tools/include/uapi/linux/fs.h to separate patch
- Add documentation
*Changes in v9:*
- Correct fault resolution for userfaultfd wp async
- Fix build warnings and errors which were happening on some configs
- Simplify pagemap ioctl's code
*Changes in v8:*
- Update uffd async wp implementation
- Improve PAGEMAP_IOCTL implementation
*Changes in v7:*
- Add uffd wp async
- Update the IOCTL to use uffd under the hood instead of soft-dirty
flags
*Motivation*
The real motivation for adding PAGEMAP_SCAN IOCTL is to emulate Windows
GetWriteWatch() syscall [1]. The GetWriteWatch{} retrieves the addresses of
the pages that are written to in a region of virtual memory.
This syscall is used in Windows applications and games etc. This syscall is
being emulated in pretty slow manner in userspace. Our purpose is to
enhance the kernel such that we translate it efficiently in a better way.
Currently some out of tree hack patches are being used to efficiently
emulate it in some kernels. We intend to replace those with these patches.
So the whole gaming on Linux can effectively get benefit from this. It
means there would be tons of users of this code.
CRIU use case [2] was mentioned by Andrei and Danylo:
> Use cases for migrating sparse VMAs are binaries sanitized with ASAN,
> MSAN or TSAN [3]. All of these sanitizers produce sparse mappings of
> shadow memory [4]. Being able to migrate such binaries allows to highly
> reduce the amount of work needed to identify and fix post-migration
> crashes, which happen constantly.
Andrei's defines the following uses of this code:
* it is more granular and allows us to track changed pages more
effectively. The current interface can clear dirty bits for the entire
process only. In addition, reading info about pages is a separate
operation. It means we must freeze the process to read information
about all its pages, reset dirty bits, only then we can start dumping
pages. The information about pages becomes more and more outdated,
while we are processing pages. The new interface solves both these
downsides. First, it allows us to read pte bits and clear the
soft-dirty bit atomically. It means that CRIU will not need to freeze
processes to pre-dump their memory. Second, it clears soft-dirty bits
for a specified region of memory. It means CRIU will have actual info
about pages to the moment of dumping them.
* The new interface has to be much faster because basic page filtering
is happening in the kernel. With the old interface, we have to read
pagemap for each page.
*Implementation Evolution (Short Summary)*
From the definition of GetWriteWatch(), we feel like kernel's soft-dirty
feature can be used under the hood with some additions like:
* reset soft-dirty flag for only a specific region of memory instead of
clearing the flag for the entire process
* get and clear soft-dirty flag for a specific region atomically
So we decided to use ioctl on pagemap file to read or/and reset soft-dirty
flag. But using soft-dirty flag, sometimes we get extra pages which weren't
even written. They had become soft-dirty because of VMA merging and
VM_SOFTDIRTY flag. This breaks the definition of GetWriteWatch(). We were
able to by-pass this short coming by ignoring VM_SOFTDIRTY until David
reported that mprotect etc messes up the soft-dirty flag while ignoring
VM_SOFTDIRTY [5]. This wasn't happening until [6] got introduced. We
discussed if we can revert these patches. But we could not reach to any
conclusion. So at this point, I made couple of tries to solve this whole
VM_SOFTDIRTY issue by correcting the soft-dirty implementation:
* [7] Correct the bug fixed wrongly back in 2014. It had potential to cause
regression. We left it behind.
* [8] Keep a list of soft-dirty part of a VMA across splits and merges. I
got the reply don't increase the size of the VMA by 8 bytes.
At this point, we left soft-dirty considering it is too much delicate and
userfaultfd [9] seemed like the only way forward. From there onward, we
have been basing soft-dirty emulation on userfaultfd wp feature where
kernel resolves the faults itself when WP_ASYNC feature is used. It was
straight forward to add WP_ASYNC feature in userfautlfd. Now we get only
those pages dirty or written-to which are really written in reality. (PS
There is another WP_UNPOPULATED userfautfd feature is required which is
needed to avoid pre-faulting memory before write-protecting [9].)
All the different masks were added on the request of CRIU devs to create
interface more generic and better.
[1] https://learn.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-…
[2] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com
[3] https://github.com/google/sanitizers
[4] https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm#64-bit
[5] https://lore.kernel.org/all/bfcae708-db21-04b4-0bbe-712badd03071@redhat.com
[6] https://lore.kernel.org/all/20220725142048.30450-1-peterx@redhat.com/
[7] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.…
[8] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.…
[9] https://lore.kernel.org/all/20230306213925.617814-1-peterx@redhat.com
[10] https://lore.kernel.org/all/20230125144529.1630917-1-mdanylo@google.com
* Original Cover letter from v8*
Hello,
Note:
Soft-dirty pages and pages which have been written-to are synonyms. As
kernel already has soft-dirty feature inside which we have given up to
use, we are using written-to terminology while using UFFD async WP under
the hood.
This IOCTL, PAGEMAP_SCAN on pagemap file can be used to get and/or clear
the info about page table entries. The following operations are
supported in this ioctl:
- Get the information if the pages have been written-to (PAGE_IS_WRITTEN),
file mapped (PAGE_IS_FILE), present (PAGE_IS_PRESENT) or swapped
(PAGE_IS_SWAPPED).
- Write-protect the pages (PAGEMAP_WP_ENGAGE) to start finding which
pages have been written-to.
- Find pages which have been written-to and write protect the pages
(atomic PAGE_IS_WRITTEN + PAGEMAP_WP_ENGAGE)
It is possible to find and clear soft-dirty pages entirely in userspace.
But it isn't efficient:
- The mprotect and SIGSEGV handler for bookkeeping
- The userfaultfd wp (synchronous) 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/Written-to status and clear present in
the kernel.
- The pages which have been written-to can not be found in accurate way.
(Kernel's soft-dirty PTE bit + sof_dirty VMA bit shows more soft-dirty
pages than there actually are.)
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.
*(Moved to using UFFD instead of soft-dirtyi feature to find pages which
have been written-to from v7 patch series)*:
Stop using the soft-dirty flags for finding which pages have been
written to. It is too delicate and wrong as it shows more soft-dirty
pages than the actual soft-dirty pages. There is no interest in
correcting it [2][3] as this is how the feature was written years ago.
It shouldn't be updated to changed behaviour. Peter Xu has suggested
using the async version of the UFFD WP [4] as it is based inherently
on the PTEs.
So in this patch series, I've added a new mode to the UFFD which is
asynchronous version of the write protect. When this variant of the
UFFD WP is used, the page faults are resolved automatically by the
kernel. The pages which have been written-to can be found by reading
pagemap file (!PM_UFFD_WP). This feature can be used successfully to
find which pages have been written to from the time the pages were
write protected. This works just like the soft-dirty flag without
showing any extra pages which aren't soft-dirty in reality.
The information related to pages if the page is file mapped, present and
swapped is required for the CRIU project [5][6]. The addition of the
required mask, any mask, excluded mask and return masks are also required
for the CRIU project [5].
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.
The patch series include the detailed selftest which can be used as an
example for the uffd async wp test and PAGEMAP_IOCTL. It shows the
interface usages as well.
[1] https://lore.kernel.org/lkml/54d4c322-cd6e-eefd-b161-2af2b56aae24@collabora…
[2] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.…
[3] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.…
[4] https://lore.kernel.org/all/Y6Hc2d+7eTKs7AiH@x1n
[5] https://lore.kernel.org/all/YyiDg79flhWoMDZB@gmail.com/
[6] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com/
Regards,
Muhammad Usama Anjum
Muhammad Usama Anjum (4):
fs/proc/task_mmu: Implement IOCTL to get and optionally clear info
about PTEs
tools headers UAPI: Update linux/fs.h with the kernel sources
mm/pagemap: add documentation of PAGEMAP_SCAN IOCTL
selftests: mm: add pagemap ioctl tests
Peter Xu (1):
userfaultfd: UFFD_FEATURE_WP_ASYNC
Documentation/admin-guide/mm/pagemap.rst | 58 +
Documentation/admin-guide/mm/userfaultfd.rst | 35 +
fs/proc/task_mmu.c | 583 +++++++
fs/userfaultfd.c | 26 +-
include/linux/hugetlb.h | 1 +
include/linux/userfaultfd_k.h | 21 +-
include/uapi/linux/fs.h | 55 +
include/uapi/linux/userfaultfd.h | 9 +-
mm/hugetlb.c | 34 +-
mm/memory.c | 27 +-
tools/include/uapi/linux/fs.h | 55 +
tools/testing/selftests/mm/.gitignore | 2 +
tools/testing/selftests/mm/Makefile | 3 +-
tools/testing/selftests/mm/config | 1 +
tools/testing/selftests/mm/pagemap_ioctl.c | 1464 ++++++++++++++++++
tools/testing/selftests/mm/run_vmtests.sh | 4 +
16 files changed, 2354 insertions(+), 24 deletions(-)
create mode 100644 tools/testing/selftests/mm/pagemap_ioctl.c
mode change 100644 => 100755 tools/testing/selftests/mm/run_vmtests.sh
--
2.39.2