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[PATCH bpf v2 0/2] Fix elem_size not being set for inner maps

by Rhys Rustad-Elliott

Commit d937bc3449fa ("bpf: make uniform use of array->elem_size everywhere in arraymap.c") changed array_map_gen_lookup to use array->elem_size instead of round_up(map->value_size, 8) as the element size when generating code to access a value in an array map. array->elem_size, however, is not set by bpf_map_meta_alloc when initializing an BPF_MAP_TYPE_ARRAY_OF_MAPS or BPF_MAP_TYPE_HASH_OF_MAPS. This results in array_map_gen_lookup incorrectly outputting code that always accesses index 0 in the array (as the index will be calculated via a multiplication with the element size, which is incorrectly set to 0). This patchset sets elem_size on the bpf_array object when allocating an array or hash of maps to fix this and adds a selftest that accesses an array map nested within a hash of maps at a nonzero index to prevent regressions. v1: https://lore.kernel.org/bpf/95b5da7c-ee52-3ecb-0a4e-f6a7a114f269@linux.dev/ Changelog: v1 -> v2: Address comments by Martin KaFai Lau: - Directly use inner_array->elem_size instead of using round_up - Move selftests to a new patch - Use ASSERT_* macros instead of CHECK and remove duration - Remove unnecessary usleep - Shorten selftest name Rhys Rustad-Elliott (2): bpf: Fix elem_size not being set for inner maps selftests/bpf: Add access_inner_map selftest kernel/bpf/map_in_map.c | 8 +++- .../bpf/prog_tests/inner_array_lookup.c | 31 +++++++++++++ .../bpf/progs/test_inner_array_lookup.c | 45 +++++++++++++++++++ 3 files changed, 82 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/inner_array_lookup.c create mode 100644 tools/testing/selftests/bpf/progs/test_inner_array_lookup.c -- 2.40.1

2 years

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[PATCH] Documentation: kunit: Rename references to kunit_abort()

by David Gow

The kunit_abort() function has been renamed __kunit_abort(), update the references to it in the documentation. Suggested-by: Daniel Latypov <dlatypov(a)google.com> Signed-off-by: David Gow <davidgow(a)google.com> --- Documentation/dev-tools/kunit/architecture.rst | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/dev-tools/kunit/architecture.rst b/Documentation/dev-tools/kunit/architecture.rst index e95ab05342bb..f335f883f8f6 100644 --- a/Documentation/dev-tools/kunit/architecture.rst +++ b/Documentation/dev-tools/kunit/architecture.rst @@ -119,9 +119,9 @@ All expectations/assertions are formatted as: terminated immediately. - Assertions call the function: - ``void __noreturn kunit_abort(struct kunit *)``. + ``void __noreturn __kunit_abort(struct kunit *)``. - - ``kunit_abort`` calls the function: + - ``__kunit_abort`` calls the function: ``void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch)``. - ``kunit_try_catch_throw`` calls the function: -- 2.41.0.rc2.161.g9c6817b8e7-goog

2 years

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[PATCH v16 0/5] Implement IOCTL to get and optionally clear info about PTEs

by Muhammad Usama Anjum

*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 | 503 ++++++ fs/userfaultfd.c | 26 +- include/linux/userfaultfd_k.h | 21 +- include/uapi/linux/fs.h | 53 + include/uapi/linux/userfaultfd.h | 9 +- mm/hugetlb.c | 32 +- mm/memory.c | 27 +- tools/include/uapi/linux/fs.h | 53 + tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 3 +- tools/testing/selftests/mm/config | 1 + tools/testing/selftests/mm/pagemap_ioctl.c | 1459 ++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 4 + 15 files changed, 2262 insertions(+), 23 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

2 years, 1 month

2
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[PATCH][next] KVM: s390: selftests: Fix spelling mistake "initally" -> "initially"

by Colin Ian King

There is a spelling mistake in literal string. Fix it. Signed-off-by: Colin Ian King <colin.i.king(a)gmail.com> --- tools/testing/selftests/kvm/s390x/cmma_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/s390x/cmma_test.c b/tools/testing/selftests/kvm/s390x/cmma_test.c index 6d0751ea224b..576fe8ee0aec 100644 --- a/tools/testing/selftests/kvm/s390x/cmma_test.c +++ b/tools/testing/selftests/kvm/s390x/cmma_test.c @@ -656,7 +656,7 @@ struct testdef { } testlist[] = { { "migration mode and dirty tracking", test_migration_mode }, { "GET_CMMA_BITS: basic calls", test_get_cmma_basic }, - { "GET_CMMA_BITS: all pages are dirty initally", test_get_inital_dirty }, + { "GET_CMMA_BITS: all pages are dirty initially", test_get_inital_dirty }, { "GET_CMMA_BITS: holes are skipped", test_get_skip_holes }, }; -- 2.30.2

2 years, 1 month

4
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[PATCH 0/8] Remove child from struct ctl_table

by Joel Granados

This is part of the effort to remove the empty element of the ctl_table structures (used to calculate size) and replace it with an ARRAY_SIZE call. By replacing the child element in struct ctl_table with a flags element we make sure that there are no forward recursions on child nodes and therefore set ourselves up for just using an ARRAY_SIZE. We also added some self tests to make sure that we do not break anything. Patchset is separated in 4: parport fixes, selftests fixes, selftests additions and replacement of child element. Tested everything with sysctl self tests and everything seems "ok". 1. parport fixes: @mcgrof: this is related to my previous series and it plugs a sysct table leak in the parport driver. Please tell me if you want me to repost the parport series with this one stiched in. 2. Selftests fixes: Remove the prefixed zeros when passing a awk field to the awk print command because it was causing $0009 to be interpreted as $0. Replaced continue with return in sysctl.sh(test_case) so the test actually gets skipped. The skip decision is now in sysctl.sh(skip_test). 3. Selftest additions: New test to confirm that unregister actually removes targets. New test to confirm that permanently empty targets are indeed created and that no other targets can be created "on top". 4. Replaced the child pointer in struct ctl_table with a u8 flag. The flag is used to differentiate between permanently empty targets and non-empty ones. Comments/feedback greatly appreciated Best Joel Joel Granados (8): parport: plug a sysctl register leak test_sysctl: Fix test metadata getters test_sysctl: Group node sysctl test under one func test_sysctl: Add an unregister sysctl test test_sysctl: Add an option to prevent test skip test_sysclt: Test for registering a mount point sysctl: Remove debugging dump_stack sysctl: replace child with a flags var drivers/parport/procfs.c | 23 ++--- fs/proc/proc_sysctl.c | 82 ++++------------ include/linux/sysctl.h | 4 +- lib/test_sysctl.c | 91 ++++++++++++++++-- tools/testing/selftests/sysctl/sysctl.sh | 115 +++++++++++++++++------ 5 files changed, 204 insertions(+), 111 deletions(-) -- 2.30.2

2 years, 1 month

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[PATCH net-next,v2] selftests/tc-testing: replace mq with invalid parent ID

by Zhengchao Shao

The test case shown in [1] triggers the kernel to access the null pointer. Therefore, add related test cases to mq. The test results are as follows: ./tdc.py -e 0531 1..1 ok 1 0531 - Replace mq with invalid parent ID ./tdc.py -c mq 1..8 ok 1 ce7d - Add mq Qdisc to multi-queue device (4 queues) ok 2 2f82 - Add mq Qdisc to multi-queue device (256 queues) ok 3 c525 - Add duplicate mq Qdisc ok 4 128a - Delete nonexistent mq Qdisc ok 5 03a9 - Delete mq Qdisc twice ok 6 be0f - Add mq Qdisc to single-queue device ok 7 1023 - Show mq class ok 8 0531 - Replace mq with invalid parent ID [1] https://lore.kernel.org/all/20230527093747.3583502-1-shaozhengchao@huawei.c… Signed-off-by: Zhengchao Shao <shaozhengchao(a)huawei.com> --- .../tc-testing/tc-tests/qdiscs/mq.json | 25 ++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/mq.json b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/mq.json index 44fbfc6caec7..e3d2de5c184f 100644 --- a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/mq.json +++ b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/mq.json @@ -155,5 +155,28 @@ "teardown": [ "echo \"1\" > /sys/bus/netdevsim/del_device" ] - } + }, + { + "id": "0531", + "name": "Replace mq with invalid parent ID", + "category": [ + "qdisc", + "mq" + ], + "plugins": { + "requires": "nsPlugin" + }, + "setup": [ + "echo \"1 1 16\" > /sys/bus/netdevsim/new_device", + "$TC qdisc add dev $ETH root handle ffff: mq" + ], + "cmdUnderTest": "$TC qdisc replace dev $ETH parent ffff:fff1 handle ffff: mq", + "expExitCode": "2", + "verifyCmd": "$TC qdisc show dev $ETH", + "matchPattern": "qdisc [a-zA-Z0-9_]+ 0: parent ffff", + "matchCount": "16", + "teardown": [ + "echo \"1\" > /sys/bus/netdevsim/del_device" + ] + } ] -- 2.34.1

2 years, 1 month

3
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[PATCH] selftests/nolibc: remove test gettimeofday_null

by Thomas Weißschuh

gettimeofday() is not guaranteed by posix to handle a NULL value as first argument gracefully. On glibc for example it crashes. (When not going through the vdso) Link: https://lore.kernel.org/lkml/96f1134d-ce6e-4d82-ae00-1cd4038809c4@t-8ch.de/ Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net> --- tools/testing/selftests/nolibc/nolibc-test.c | 1 - 1 file changed, 1 deletion(-) diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 7de46305f419..0fe615ebb086 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -583,7 +583,6 @@ int run_syscall(int min, int max) CASE_TEST(fork); EXPECT_SYSZR(1, test_fork()); break; CASE_TEST(getdents64_root); EXPECT_SYSNE(1, test_getdents64("/"), -1); break; CASE_TEST(getdents64_null); EXPECT_SYSER(1, test_getdents64("/dev/null"), -1, ENOTDIR); break; - CASE_TEST(gettimeofday_null); EXPECT_SYSZR(1, gettimeofday(NULL, NULL)); break; #ifdef NOLIBC CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break; CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break; --- base-commit: 5b21219d67d3483144d10332709d0c04f733ab93 change-id: 20230530-nolibc-gettimeofday-6c72a10ba1a3 Best regards, -- Thomas Weißschuh <linux(a)weissschuh.net>

2 years, 1 month

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[PATCH bpf] bpf: Fix elem_size not being set for inner maps

by Rhys Rustad-Elliott

Commit d937bc3449fa ("bpf: make uniform use of array->elem_size everywhere in arraymap.c") changed array_map_gen_lookup to use array->elem_size instead of round_up(map->value_size, 8) as the element size when generating code to access a value in an array map. array->elem_size, however, is not set by bpf_map_meta_alloc when initializing an BPF_MAP_TYPE_ARRAY_OF_MAPS or BPF_MAP_TYPE_HASH_OF_MAPS. This results in array_map_gen_lookup incorrectly outputting code that always accesses index 0 in the array (as the index will be calculated via a multiplication with the element size, which is incorrectly set to 0). Set elem_size on the bpf_array object when allocating an array or hash of maps and add a selftest that accesses an inner map at a nonzero index to prevent regressions. Fixes: d937bc3449fa ("bpf: make uniform use of array->elem_size everywhere in arraymap.c") Signed-off-by: Rhys Rustad-Elliott <me(a)rhysre.net> --- kernel/bpf/map_in_map.c | 8 +++- .../map_in_map_inner_array_lookup.c | 33 ++++++++++++++ .../test_map_in_map_inner_array_lookup.c | 45 +++++++++++++++++++ 3 files changed, 84 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/map_in_map_inner_array_lookup.c create mode 100644 tools/testing/selftests/bpf/progs/test_map_in_map_inner_array_lookup.c diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c index 2c5c64c2a53b..8d65b12e0834 100644 --- a/kernel/bpf/map_in_map.c +++ b/kernel/bpf/map_in_map.c @@ -69,9 +69,13 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) /* Misc members not needed in bpf_map_meta_equal() check. */ inner_map_meta->ops = inner_map->ops; if (inner_map->ops == &array_map_ops) { + struct bpf_array *inner_array_meta = + container_of(inner_map_meta, struct bpf_array, map); + struct bpf_array *inner_array = container_of(inner_map, struct bpf_array, map); + + inner_array_meta->index_mask = inner_array->index_mask; + inner_array_meta->elem_size = round_up(inner_map->value_size, 8); inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1; - container_of(inner_map_meta, struct bpf_array, map)->index_mask = - container_of(inner_map, struct bpf_array, map)->index_mask; } fdput(f); diff --git a/tools/testing/selftests/bpf/prog_tests/map_in_map_inner_array_lookup.c b/tools/testing/selftests/bpf/prog_tests/map_in_map_inner_array_lookup.c new file mode 100644 index 000000000000..264d4788e5fd --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/map_in_map_inner_array_lookup.c @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <test_progs.h> + +#include "test_map_in_map_inner_array_lookup.skel.h" + +static int duration; + +void test_map_in_map_inner_array_lookup(void) +{ + int map1_fd, err; + int key = 3; + int val = 1; + struct test_map_in_map_inner_array_lookup *skel; + + skel = test_map_in_map_inner_array_lookup__open_and_load(); + if (CHECK(!skel, "skel_open", "failed to open&load skeleton\n")) + return; + + err = test_map_in_map_inner_array_lookup__attach(skel); + if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err)) + goto cleanup; + + map1_fd = bpf_map__fd(skel->maps.inner_map1); + bpf_map_update_elem(map1_fd, &key, &val, 0); + usleep(1); + /* Probe should have set the element at index 3 to 2 */ + bpf_map_lookup_elem(map1_fd, &key, &val); + CHECK(val != 2, "inner1", "got %d != exp %d\n", val, 2); + +cleanup: + test_map_in_map_inner_array_lookup__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_map_in_map_inner_array_lookup.c b/tools/testing/selftests/bpf/progs/test_map_in_map_inner_array_lookup.c new file mode 100644 index 000000000000..c2c8f2fa451d --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_map_in_map_inner_array_lookup.c @@ -0,0 +1,45 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +struct inner_map { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 5); + __type(key, int); + __type(value, int); +} inner_map1 SEC(".maps"); + +struct outer_map { + __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS); + __uint(max_entries, 3); + __type(key, int); + __array(values, struct inner_map); +} outer_map1 SEC(".maps") = { + .values = { + [2] = &inner_map1, + }, +}; + +SEC("raw_tp/sys_enter") +int handle__sys_enter(void *ctx) +{ + int outer_key = 2, inner_key = 3; + int *val; + void *map; + + map = bpf_map_lookup_elem(&outer_map1, &outer_key); + if (!map) + return 1; + + val = bpf_map_lookup_elem(map, &inner_key); + if (!val) + return 1; + + if (*val == 1) + *val = 2; + + return 0; +} + +char _license[] SEC("license") = "GPL"; -- 2.40.1

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[PATCH 0/6] Memory Mapping (VMA) protection using PKU - set 1

by jeffxu＠chromium.org

From: Jeff Xu <jeffxu(a)google.com> This is the first set of Memory mapping (VMA) protection patches using PKU. * * * Background: As discussed previously in the kernel mailing list [1], V8 CFI [2] uses PKU to protect memory, and Stephen Röttger proposes to extend the PKU to memory mapping [3]. We're using PKU for in-process isolation to enforce control-flow integrity for a JIT compiler. In our threat model, an attacker exploits a vulnerability and has arbitrary read/write access to the whole process space concurrently to other threads being executed. This attacker can manipulate some arguments to syscalls from some threads. Under such a powerful attack, we want to create a “safe/isolated” thread environment. We assign dedicated PKUs to this thread, and use those PKUs to protect the threads’ runtime environment. The thread has exclusive access to its run-time memory. This includes modifying the protection of the memory mapping, or munmap the memory mapping after use. And the other threads won’t be able to access the memory or modify the memory mapping (VMA) belonging to the thread. * * * Proposed changes: This patch introduces a new flag, PKEY_ENFORCE_API, to the pkey_alloc() function. When a PKEY is created with this flag, it is enforced that any thread that wants to make changes to the memory mapping (such as mprotect) of the memory must have write access to the PKEY. PKEYs created without this flag will continue to work as they do now, for backwards compatibility. Only PKEY created from user space can have the new flag set, the PKEY allocated by the kernel internally will not have it. In other words, ARCH_DEFAULT_PKEY(0) and execute_only_pkey won’t have this flag set, and continue work as today. This flag is checked only at syscall entry, such as mprotect/munmap in this set of patches. It will not apply to other call paths. In other words, if the kernel want to change attributes of VMA for some reasons, the kernel is free to do that and not affected by this new flag. This set of patch covers mprotect/munmap, I plan to work on other syscalls after this. * * * Testing: I have tested this patch on a Linux kernel 5.15, 6,1, and 6.4-rc1, new selftest is added in: pkey_enforce_api.c * * * Discussion: We believe that this patch provides a valuable security feature. It allows us to create “safe/isolated” thread environments that are protected from attackers with arbitrary read/write access to the process space. We believe that the interface change and the patch don't introduce backwards compatibility risk. We would like to disucss this patch in Linux kernel community for feedback and support. * * * Reference: [1]https://lore.kernel.org/all/202208221331.71C50A6F@keescook/ [2]https://docs.google.com/document/d/1O2jwK4dxI3nRcOJuPYkonhTkNQfbmwdvxQMyX… [3]https://docs.google.com/document/d/1qqVoVfRiF2nRylL3yjZyCQvzQaej1HRPh3f5w… Best Regards, -Jeff Xu Jeff Xu (6): PKEY: Introduce PKEY_ENFORCE_API flag PKEY: Add arch_check_pkey_enforce_api() PKEY: Apply PKEY_ENFORCE_API to mprotect PKEY:selftest pkey_enforce_api for mprotect KEY: Apply PKEY_ENFORCE_API to munmap PKEY:selftest pkey_enforce_api for munmap arch/powerpc/include/asm/pkeys.h | 19 +- arch/x86/include/asm/mmu.h | 7 + arch/x86/include/asm/pkeys.h | 92 +- arch/x86/mm/pkeys.c | 2 +- include/linux/mm.h | 2 +- include/linux/pkeys.h | 18 +- include/uapi/linux/mman.h | 5 + mm/mmap.c | 34 +- mm/mprotect.c | 31 +- mm/mremap.c | 6 +- tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/pkey_enforce_api.c | 1312 +++++++++++++++++ 12 files changed, 1507 insertions(+), 22 deletions(-) create mode 100644 tools/testing/selftests/mm/pkey_enforce_api.c base-commit: ba0ad6ed89fd5dada3b7b65ef2b08e95d449d4ab -- 2.40.1.606.ga4b1b128d6-goog

2 years, 1 month

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[PATCH v2 5/6] cgroup/cpuset: Documentation update for partition

by Waiman Long

This patch updates the cgroup-v2.rst file to include information about the new "cpuset.cpus.reserve" control file as well as the new remote partition. Signed-off-by: Waiman Long <longman(a)redhat.com> --- Documentation/admin-guide/cgroup-v2.rst | 92 +++++++++++++++++++++---- 1 file changed, 79 insertions(+), 13 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index f67c0829350b..3e9351c2cd27 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -2215,6 +2215,38 @@ Cpuset Interface Files Its value will be affected by memory nodes hotplug events. + cpuset.cpus.reserve + A read-write multiple values file which exists only on root + cgroup. + + It lists all the CPUs that are reserved for adjacent and remote + partitions created in the system. See the next section for + more information on what an adjacent or remote partitions is. + + Creation of adjacent partition does not require touching this + control file as CPU reservation will be done automatically. + In order to create a remote partition, the CPUs needed by the + remote partition has to be written to this file first. + + Due to the fact that "cpuset.cpus.reserve" holds reserve CPUs + that can be used by multiple partitions and automatic reservation + may also race with manual reservation, an extension prefixes of + "+" and "-" are allowed for this file to reduce race. + + A "+" prefix can be used to indicate a list of additional + CPUs that are to be added without disturbing the CPUs that are + originally there. For example, if its current value is "3-4", + echoing ""+5" to it will change it to "3-5". + + Once a remote partition is destroyed, its CPUs have to be + removed from this file or no other process can use them. A "-" + prefix can be used to remove a list of CPUs from it. However, + removing CPUs that are currently used in existing partitions + may cause those partitions to become invalid. A single "-" + character without any number can be used to indicate removal + of all the free CPUs not yet allocated to any partitions to + avoid accidental partition invalidation. + cpuset.cpus.partition A read-write single value file which exists on non-root cpuset-enabled cgroups. This flag is owned by the parent cgroup @@ -2228,25 +2260,49 @@ Cpuset Interface Files "isolated" Partition root without load balancing ========== ===================================== - The root cgroup is always a partition root and its state - cannot be changed. All other non-root cgroups start out as - "member". + A cpuset partition is a collection of cgroups with a partition + root at the top of the hierarchy and its descendants except + those that are separate partition roots themselves and their + descendants. A partition has exclusive access to the set of + CPUs allocated to it. Other cgroups outside of that partition + cannot use any CPUs in that set. + + There are two types of partitions - adjacent and remote. The + parent of an adjacent partition must be a valid partition root. + Partition roots of adjacent partitions are all clustered around + the root cgroup. Creation of adjacent partition is done by + writing the desired partition type into "cpuset.cpus.partition". + + A remote partition does not require a partition root parent. + So a remote partition can be formed far from the root cgroup. + However, its creation is a 2-step process. The CPUs needed + by a remote partition ("cpuset.cpus" of the partition root) + has to be written into "cpuset.cpus.reserve" of the root + cgroup first. After that, "isolated" can be written into + "cpuset.cpus.partition" of the partition root to form a remote + isolated partition which is the only supported remote partition + type for now. + + All remote partitions are terminal as adjacent partition cannot + be created underneath it. With the way remote partition is + formed, it is not possible to create another valid remote + partition underneath it. + + The root cgroup is always a partition root and its state cannot + be changed. All other non-root cgroups start out as "member". When set to "root", the current cgroup is the root of a new - partition or scheduling domain that comprises itself and all - its descendants except those that are separate partition roots - themselves and their descendants. + partition or scheduling domain. - When set to "isolated", the CPUs in that partition root will + When set to "isolated", the CPUs in that partition will be in an isolated state without any load balancing from the scheduler. Tasks placed in such a partition with multiple CPUs should be carefully distributed and bound to each of the individual CPUs for optimal performance. - The value shown in "cpuset.cpus.effective" of a partition root - is the CPUs that the partition root can dedicate to a potential - new child partition root. The new child subtracts available - CPUs from its parent "cpuset.cpus.effective". + The value shown in "cpuset.cpus.effective" of a partition root is + the CPUs that are dedicated to that partition and not available + to cgroups outside of that partittion. A partition root ("root" or "isolated") can be in one of the two possible states - valid or invalid. An invalid partition @@ -2270,8 +2326,8 @@ Cpuset Interface Files In the case of an invalid partition root, a descriptive string on why the partition is invalid is included within parentheses. - For a partition root to become valid, the following conditions - must be met. + For an adjacent partition root to be valid, the following + conditions must be met. 1) The "cpuset.cpus" is exclusive with its siblings , i.e. they are not shared by any of its siblings (exclusivity rule). @@ -2281,6 +2337,16 @@ Cpuset Interface Files 4) The "cpuset.cpus.effective" cannot be empty unless there is no task associated with this partition. + For a remote partition root to be valid, the following conditions + must be met. + + 1) The same exclusivity rule as adjacent partition root. + 2) The "cpuset.cpus" is not empty and all the CPUs must be + present in "cpuset.cpus.reserve" of the root cgroup and none + of them are allocated to another partition. + 3) The "cpuset.cpus" value must be present in all its ancestors + to ensure proper hierarchical cpu distribution. + External events like hotplug or changes to "cpuset.cpus" can cause a valid partition root to become invalid and vice versa. Note that a task cannot be moved to a cgroup with empty -- 2.31.1

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