July 2025 - Linux-kselftest-mirror

[PATCH v2 1/2] selftests: cachestat: add tests for mmap

by Suresh K C

From: Suresh K C <suresh.k.chandrappa(a)gmail.com> Add a test case to verify cachestat behavior with memory-mapped files using mmap(). This ensures that pages accessed via mmap are correctly accounted for in the page cache. Tested on x86_64 with default kernel config Signed-off-by: Suresh K C <suresh.k.chandrappa(a)gmail.com> --- .../selftests/cachestat/test_cachestat.c | 39 ++++++++++++++++--- 1 file changed, 33 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/cachestat/test_cachestat.c b/tools/testing/selftests/cachestat/test_cachestat.c index 632ab44737ec..b6452978dae0 100644 --- a/tools/testing/selftests/cachestat/test_cachestat.c +++ b/tools/testing/selftests/cachestat/test_cachestat.c @@ -33,6 +33,11 @@ void print_cachestat(struct cachestat *cs) cs->nr_evicted, cs->nr_recently_evicted); } +enum file_type { + FILE_MMAP, + FILE_SHMEM +}; + bool write_exactly(int fd, size_t filesize) { int random_fd = open("/dev/urandom", O_RDONLY); @@ -202,7 +207,7 @@ static int test_cachestat(const char *filename, bool write_random, bool create, return ret; } -bool test_cachestat_shmem(void) +bool run_cachestat_test(enum file_type type) { size_t PS = sysconf(_SC_PAGESIZE); size_t filesize = PS * 512 * 2; /* 2 2MB huge pages */ @@ -212,27 +217,43 @@ bool test_cachestat_shmem(void) char *filename = "tmpshmcstat"; struct cachestat cs; bool ret = true; + int fd; unsigned long num_pages = compute_len / PS; - int fd = shm_open(filename, O_CREAT | O_RDWR, 0600); + if (type == FILE_SHMEM) + fd = shm_open(filename, O_CREAT | O_RDWR, 0600); + else + fd = open(filename, O_RDWR | O_CREAT | O_TRUNC, 0666); if (fd < 0) { - ksft_print_msg("Unable to create shmem file.\n"); + ksft_print_msg("Unable to create file.\n"); ret = false; goto out; } if (ftruncate(fd, filesize)) { - ksft_print_msg("Unable to truncate shmem file.\n"); + ksft_print_msg("Unable to truncate file.\n"); ret = false; goto close_fd; } if (!write_exactly(fd, filesize)) { - ksft_print_msg("Unable to write to shmem file.\n"); + ksft_print_msg("Unable to write to file.\n"); ret = false; goto close_fd; } + if (type == FILE_MMAP){ + char *map = mmap(NULL, filesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (map == MAP_FAILED) { + ksft_print_msg("mmap failed.\n"); + ret = false; + goto close_fd; + } + for (int i = 0; i < filesize; i++) { + map[i] = 'A'; + } + map[filesize - 1] = 'X'; + } syscall_ret = syscall(__NR_cachestat, fd, &cs_range, &cs, 0); if (syscall_ret) { @@ -308,12 +329,18 @@ int main(void) break; } - if (test_cachestat_shmem()) + if (run_cachestat_test(FILE_SHMEM)) ksft_test_result_pass("cachestat works with a shmem file\n"); else { ksft_test_result_fail("cachestat fails with a shmem file\n"); ret = 1; } + if (run_cachestat_test(FILE_MMAP)) + ksft_test_result_pass("cachestat works with a mmap file\n"); + else { + ksft_test_result_fail("cachestat fails with a mmap file\n"); + ret = 1; + } return ret; } -- 2.43.0

16 hours, 25 minutes

1
1
0 0

[PATCH v2 0/6] VMM can handle guest SEA via KVM_EXIT_ARM_SEA

by Jiaqi Yan

Problem ======= When host APEI is unable to claim synchronous external abort (SEA) during stage-2 guest abort, today KVM directly injects an async SError into the VCPU then resumes it. The injected SError usually results in unpleasant guest kernel panic. One of the major situation of guest SEA is when VCPU consumes recoverable uncorrected memory error (UER), which is not uncommon at all in modern datacenter servers with large amounts of physical memory. Although SError and guest panic is sufficient to stop the propagation of corrupted memory there is room to recover from an UER in a more graceful manner. Proposed Solution ================= Alternatively KVM can replay the SEA to the faulting VCPU, via existing KVM_SET_VCPU_EVENTS API. If the memory poison consumption or the fault that cause SEA is not from guest kernel, the blast radius can be limited to the consuming or faulting guest userspace process, so the VM can keep running. In addition, instead of doing under the hood without involving userspace, there are benefits to redirect the SEA to VMM: - VM customers care about the disruptions caused by memory errors, and VMM usually has the responsibility to start the process of notifying the customers of memory error events in their VMs. For example some cloud provider emits a critical log in their observability UI [1], and provides playbook for customers on how to mitigate disruptions to their workloads. - VMM can protect future memory error consumption by unmapping the poisoned pages from stage-2 page table with KVM userfault, or by splitting the memslot that contains the poisoned guest pages [2]. - VMM can keep track of SEA events in the VM. When VMM thinks the status on the host or the VM is bad enough, e.g. number of distinct SEAs exceeds a threshold, it can restart the VM on another healthy host. - Behavior parity with x86 architecture. When machine check exception (MCE) is caused by VCPU, kernel or KVM signals userspace SIGBUS to let VMM either recover from the MCE, or terminate itself with VM. The prior RFC proposes to implement SIGBUS on arm64 as well, but Marc preferred VCPU exit over signal [3]. However, implementation aside, returning SEA to VMM is on par with returning MCE to VMM. Once SEA is redirected to VMM, among other actions, VMM is encouraged to inject external aborts into the faulting VCPU, which is already supported by KVM on arm64. We notice injecting instruction abort is not fully supported by KVM_SET_VCPU_EVENTS. Complement it in the patchset. New UAPIs ========= This patchset introduces following userspace-visiable changes to empower VMM to control what happens next for SEA on guest memory: - KVM_CAP_ARM_SEA_TO_USER. While taking SEA, if userspace has enabled this new capability at VM creation, and the SEA is not caused by memory allocated for stage-2 translation table, instead of injecting SError, return KVM_EXIT_ARM_SEA to userspace. - KVM_EXIT_ARM_SEA. This is the VM exit reason VMM gets. The details about the SEA is provided in arm_sea as much as possible, including sanitized ESR value at EL2, if guest virtual and physical addresses (GPA and GVA) are available and the values if available. - KVM_CAP_ARM_INJECT_EXT_IABT. VMM today can inject external data abort to VCPU via KVM_SET_VCPU_EVENTS API. However, in case of instruction abort, VMM cannot inject it via KVM_SET_VCPU_EVENTS. KVM_CAP_ARM_INJECT_EXT_IABT is just a natural extend to KVM_CAP_ARM_INJECT_EXT_DABT that tells VMM KVM_SET_VCPU_EVENTS now supports external instruction abort. * From v1 [4]: - Rebased on commit 4d62121ce9b5 ("KVM: arm64: vgic-debug: Avoid dereferencing NULL ITE pointer"). - Sanitize ESR_EL2 before reporting it to userspace. - Do not do KVM_EXIT_ARM_SEA when SEA is caused by memory allocated to stage-2 translation table. [1] https://cloud.google.com/solutions/sap/docs/manage-host-errors [2] https://lore.kernel.org/kvm/20250109204929.1106563-1-jthoughton@google.com [3] https://lore.kernel.org/kvm/86pljbqqh0.wl-maz@kernel.org [4] https://lore.kernel.org/kvm/20250505161412.1926643-1-jiaqiyan@google.com Jiaqi Yan (5): KVM: arm64: VM exit to userspace to handle SEA KVM: arm64: Set FnV for VCPU when FAR_EL2 is invalid KVM: selftests: Test for KVM_EXIT_ARM_SEA and KVM_CAP_ARM_SEA_TO_USER KVM: selftests: Test for KVM_CAP_INJECT_EXT_IABT Documentation: kvm: new uAPI for handling SEA Raghavendra Rao Ananta (1): KVM: arm64: Allow userspace to inject external instruction aborts Documentation/virt/kvm/api.rst | 128 ++++++- arch/arm64/include/asm/kvm_emulate.h | 67 ++++ arch/arm64/include/asm/kvm_host.h | 8 + arch/arm64/include/asm/kvm_ras.h | 2 +- arch/arm64/include/uapi/asm/kvm.h | 3 +- arch/arm64/kvm/arm.c | 6 + arch/arm64/kvm/guest.c | 13 +- arch/arm64/kvm/inject_fault.c | 3 + arch/arm64/kvm/mmu.c | 59 ++- include/uapi/linux/kvm.h | 12 + tools/arch/arm64/include/asm/esr.h | 2 + tools/arch/arm64/include/uapi/asm/kvm.h | 3 +- tools/testing/selftests/kvm/Makefile.kvm | 2 + .../testing/selftests/kvm/arm64/inject_iabt.c | 98 +++++ .../testing/selftests/kvm/arm64/sea_to_user.c | 340 ++++++++++++++++++ tools/testing/selftests/kvm/lib/kvm_util.c | 1 + 16 files changed, 718 insertions(+), 29 deletions(-) create mode 100644 tools/testing/selftests/kvm/arm64/inject_iabt.c create mode 100644 tools/testing/selftests/kvm/arm64/sea_to_user.c -- 2.49.0.1266.g31b7d2e469-goog

17 hours, 38 minutes

1
7
0 0

[PATCH v4 0/6] replace `allow(...)` lints with `expect(...)`

by Onur Özkan

Changes in v4: - The first patch from previous versions is now broken down into multiple smaller patches. - `#![expect(dead_code)]` is reverted from `rust/kernel/opp.rs` as it failed on the kernel test bot (see [1] for more). Link: https://lore.kernel.org/all/202506291507.M9eg5kic-lkp@intel.com [1] Onur Özkan (6): rust: switch to `#[expect(...)]` in core modules rust: switch to `#[expect(...)]` in init and kunit drivers: gpu: switch to `#[expect(...)]` in nova-core/regs.rs rust: switch to `#[expect(...)]` in devres, driver and ioctl rust: remove `#[allow(clippy::unnecessary_cast)]` rust: remove `#[allow(clippy::non_send_fields_in_send_ty)]` drivers/gpu/nova-core/regs.rs | 2 +- rust/kernel/alloc/allocator_test.rs | 2 +- rust/kernel/cpufreq.rs | 1 - rust/kernel/devres.rs | 2 +- rust/kernel/driver.rs | 2 +- rust/kernel/drm/ioctl.rs | 8 ++++---- rust/kernel/error.rs | 3 +-- rust/kernel/init.rs | 6 +++--- rust/kernel/kunit.rs | 2 +- rust/kernel/types.rs | 2 +- rust/macros/helpers.rs | 2 +- 11 files changed, 15 insertions(+), 17 deletions(-) -- 2.50.0

17 hours, 46 minutes

3
9
0 0

[PATCH v13 0/5] rust: replace kernel::str::CStr w/ core::ffi::CStr

by Tamir Duberstein

This picks up from Michal Rostecki's work[0]. Per Michal's guidance I have omitted Co-authored tags, as the end result is quite different. Link: https://lore.kernel.org/rust-for-linux/20240819153656.28807-2-vadorovsky@pr… [0] Closes: https://github.com/Rust-for-Linux/linux/issues/1075 Signed-off-by: Tamir Duberstein <tamird(a)gmail.com> --- Changes in v13: - Rebase on v6.16-rc4. - Link to v12: https://lore.kernel.org/r/20250619-cstr-core-v12-0-80c9c7b45900@gmail.com Changes in v12: - Introduce `kernel::fmt::Display` to allow implementations on foreign types. - Tidy up doc comment on `str_to_cstr`. (Alice Ryhl). - Link to v11: https://lore.kernel.org/r/20250530-cstr-core-v11-0-cd9c0cbcb902@gmail.com Changes in v11: - Use `quote_spanned!` to avoid `use<'a, T>` and generally reduce manual token construction. - Add a commit to simplify `quote_spanned!`. - Drop first commit in favor of https://lore.kernel.org/rust-for-linux/20240906164448.2268368-1-paddymills@…. (Miguel Ojeda) - Correctly handle expressions such as `pr_info!("{a}", a = a = a)`. (Benno Lossin) - Avoid dealing with `}}` escapes, which is not needed. (Benno Lossin) - Revert some unnecessary changes. (Benno Lossin) - Rename `c_str_avoid_literals!` to `str_to_cstr!`. (Benno Lossin & Alice Ryhl). - Link to v10: https://lore.kernel.org/r/20250524-cstr-core-v10-0-6412a94d9d75@gmail.com Changes in v10: - Rebase on cbeaa41dfe26b72639141e87183cb23e00d4b0dd. - Implement Alice's suggestion to use a proc macro to work around orphan rules otherwise preventing `core::ffi::CStr` to be directly printed with `{}`. - Link to v9: https://lore.kernel.org/r/20250317-cstr-core-v9-0-51d6cc522f62@gmail.com Changes in v9: - Rebase on rust-next. - Restore `impl Display for BStr` which exists upstream[1]. - Link: https://doc.rust-lang.org/nightly/std/bstr/struct.ByteStr.html#impl-Display… [1] - Link to v8: https://lore.kernel.org/r/20250203-cstr-core-v8-0-cb3f26e78686@gmail.com Changes in v8: - Move `{from,as}_char_ptr` back to `CStrExt`. This reduces the diff some. - Restore `from_bytes_with_nul_unchecked_mut`, `to_cstring`. - Link to v7: https://lore.kernel.org/r/20250202-cstr-core-v7-0-da1802520438@gmail.com Changes in v7: - Rebased on mainline. - Restore functionality added in commit a321f3ad0a5d ("rust: str: add {make,to}_{upper,lower}case() to CString"). - Used `diff.algorithm patience` to improve diff readability. - Link to v6: https://lore.kernel.org/r/20250202-cstr-core-v6-0-8469cd6d29fd@gmail.com Changes in v6: - Split the work into several commits for ease of review. - Restore `{from,as}_char_ptr` to allow building on ARM (see commit message). - Add `CStrExt` to `kernel::prelude`. (Alice Ryhl) - Remove `CStrExt::from_bytes_with_nul_unchecked_mut` and restore `DerefMut for CString`. (Alice Ryhl) - Rename and hide `kernel::c_str!` to encourage use of C-String literals. - Drop implementation and invocation changes in kunit.rs. (Trevor Gross) - Drop docs on `Display` impl. (Trevor Gross) - Rewrite docs in the style of the standard library. - Restore the `test_cstr_debug` unit tests to demonstrate that the implementation has changed. Changes in v5: - Keep the `test_cstr_display*` unit tests. Changes in v4: - Provide the `CStrExt` trait with `display()` method, which returns a `CStrDisplay` wrapper with `Display` implementation. This addresses the lack of `Display` implementation for `core::ffi::CStr`. - Provide `from_bytes_with_nul_unchecked_mut()` method in `CStrExt`, which might be useful and is going to prevent manual, unsafe casts. - Fix a typo (s/preffered/prefered/). Changes in v3: - Fix the commit message. - Remove redundant braces in `use`, when only one item is imported. Changes in v2: - Do not remove `c_str` macro. While it's preferred to use C-string literals, there are two cases where `c_str` is helpful: - When working with macros, which already return a Rust string literal (e.g. `stringify!`). - When building macros, where we want to take a Rust string literal as an argument (for caller's convenience), but still use it as a C-string internally. - Use Rust literals as arguments in macros (`new_mutex`, `new_condvar`, `new_mutex`). Use the `c_str` macro to convert these literals to C-string literals. - Use `c_str` in kunit.rs for converting the output of `stringify!` to a `CStr`. - Remove `DerefMut` implementation for `CString`. --- Tamir Duberstein (5): rust: macros: reduce collections in `quote!` macro rust: support formatting of foreign types rust: replace `CStr` with `core::ffi::CStr` rust: replace `kernel::c_str!` with C-Strings rust: remove core::ffi::CStr reexport drivers/block/rnull.rs | 4 +- drivers/cpufreq/rcpufreq_dt.rs | 5 +- drivers/gpu/drm/drm_panic_qr.rs | 5 +- drivers/gpu/drm/nova/driver.rs | 10 +- drivers/gpu/nova-core/driver.rs | 6 +- drivers/gpu/nova-core/firmware.rs | 2 +- drivers/gpu/nova-core/gpu.rs | 4 +- drivers/gpu/nova-core/nova_core.rs | 2 +- drivers/net/phy/ax88796b_rust.rs | 8 +- drivers/net/phy/qt2025.rs | 6 +- rust/kernel/auxiliary.rs | 6 +- rust/kernel/block/mq.rs | 2 +- rust/kernel/clk.rs | 9 +- rust/kernel/configfs.rs | 14 +- rust/kernel/cpufreq.rs | 6 +- rust/kernel/device.rs | 9 +- rust/kernel/devres.rs | 2 +- rust/kernel/driver.rs | 4 +- rust/kernel/drm/device.rs | 4 +- rust/kernel/drm/driver.rs | 3 +- rust/kernel/drm/ioctl.rs | 2 +- rust/kernel/error.rs | 10 +- rust/kernel/faux.rs | 5 +- rust/kernel/firmware.rs | 16 +- rust/kernel/fmt.rs | 89 +++++++ rust/kernel/kunit.rs | 28 +-- rust/kernel/lib.rs | 3 +- rust/kernel/miscdevice.rs | 5 +- rust/kernel/net/phy.rs | 12 +- rust/kernel/of.rs | 5 +- rust/kernel/pci.rs | 2 +- rust/kernel/platform.rs | 6 +- rust/kernel/prelude.rs | 5 +- rust/kernel/print.rs | 4 +- rust/kernel/seq_file.rs | 6 +- rust/kernel/str.rs | 444 ++++++++++------------------------ rust/kernel/sync.rs | 7 +- rust/kernel/sync/completion.rs | 2 +- rust/kernel/sync/condvar.rs | 4 +- rust/kernel/sync/lock.rs | 4 +- rust/kernel/sync/lock/global.rs | 6 +- rust/kernel/sync/poll.rs | 1 + rust/kernel/workqueue.rs | 9 +- rust/macros/fmt.rs | 99 ++++++++ rust/macros/kunit.rs | 10 +- rust/macros/lib.rs | 19 ++ rust/macros/module.rs | 2 +- rust/macros/quote.rs | 111 ++++----- samples/rust/rust_configfs.rs | 9 +- samples/rust/rust_driver_auxiliary.rs | 7 +- samples/rust/rust_driver_faux.rs | 4 +- samples/rust/rust_driver_pci.rs | 4 +- samples/rust/rust_driver_platform.rs | 4 +- samples/rust/rust_misc_device.rs | 3 +- scripts/rustdoc_test_gen.rs | 6 +- 55 files changed, 543 insertions(+), 521 deletions(-) --- base-commit: 769e324b66b0d92d04f315d0c45a0f72737c7494 change-id: 20250201-cstr-core-d4b9b69120cf Best regards, -- Tamir Duberstein <tamird(a)gmail.com>

18 hours, 6 minutes

2
6
0 0

[PATCH v12 0/5] rust: replace kernel::str::CStr w/ core::ffi::CStr

by Tamir Duberstein

This picks up from Michal Rostecki's work[0]. Per Michal's guidance I have omitted Co-authored tags, as the end result is quite different. Link: https://lore.kernel.org/rust-for-linux/20240819153656.28807-2-vadorovsky@pr… [0] Closes: https://github.com/Rust-for-Linux/linux/issues/1075 Signed-off-by: Tamir Duberstein <tamird(a)gmail.com> --- Changes in v12: - Introduce `kernel::fmt::Display` to allow implementations on foreign types. - Tidy up doc comment on `str_to_cstr`. (Alice Ryhl). - Link to v11: https://lore.kernel.org/r/20250530-cstr-core-v11-0-cd9c0cbcb902@gmail.com Changes in v11: - Use `quote_spanned!` to avoid `use<'a, T>` and generally reduce manual token construction. - Add a commit to simplify `quote_spanned!`. - Drop first commit in favor of https://lore.kernel.org/rust-for-linux/20240906164448.2268368-1-paddymills@…. (Miguel Ojeda) - Correctly handle expressions such as `pr_info!("{a}", a = a = a)`. (Benno Lossin) - Avoid dealing with `}}` escapes, which is not needed. (Benno Lossin) - Revert some unnecessary changes. (Benno Lossin) - Rename `c_str_avoid_literals!` to `str_to_cstr!`. (Benno Lossin & Alice Ryhl). - Link to v10: https://lore.kernel.org/r/20250524-cstr-core-v10-0-6412a94d9d75@gmail.com Changes in v10: - Rebase on cbeaa41dfe26b72639141e87183cb23e00d4b0dd. - Implement Alice's suggestion to use a proc macro to work around orphan rules otherwise preventing `core::ffi::CStr` to be directly printed with `{}`. - Link to v9: https://lore.kernel.org/r/20250317-cstr-core-v9-0-51d6cc522f62@gmail.com Changes in v9: - Rebase on rust-next. - Restore `impl Display for BStr` which exists upstream[1]. - Link: https://doc.rust-lang.org/nightly/std/bstr/struct.ByteStr.html#impl-Display… [1] - Link to v8: https://lore.kernel.org/r/20250203-cstr-core-v8-0-cb3f26e78686@gmail.com Changes in v8: - Move `{from,as}_char_ptr` back to `CStrExt`. This reduces the diff some. - Restore `from_bytes_with_nul_unchecked_mut`, `to_cstring`. - Link to v7: https://lore.kernel.org/r/20250202-cstr-core-v7-0-da1802520438@gmail.com Changes in v7: - Rebased on mainline. - Restore functionality added in commit a321f3ad0a5d ("rust: str: add {make,to}_{upper,lower}case() to CString"). - Used `diff.algorithm patience` to improve diff readability. - Link to v6: https://lore.kernel.org/r/20250202-cstr-core-v6-0-8469cd6d29fd@gmail.com Changes in v6: - Split the work into several commits for ease of review. - Restore `{from,as}_char_ptr` to allow building on ARM (see commit message). - Add `CStrExt` to `kernel::prelude`. (Alice Ryhl) - Remove `CStrExt::from_bytes_with_nul_unchecked_mut` and restore `DerefMut for CString`. (Alice Ryhl) - Rename and hide `kernel::c_str!` to encourage use of C-String literals. - Drop implementation and invocation changes in kunit.rs. (Trevor Gross) - Drop docs on `Display` impl. (Trevor Gross) - Rewrite docs in the style of the standard library. - Restore the `test_cstr_debug` unit tests to demonstrate that the implementation has changed. Changes in v5: - Keep the `test_cstr_display*` unit tests. Changes in v4: - Provide the `CStrExt` trait with `display()` method, which returns a `CStrDisplay` wrapper with `Display` implementation. This addresses the lack of `Display` implementation for `core::ffi::CStr`. - Provide `from_bytes_with_nul_unchecked_mut()` method in `CStrExt`, which might be useful and is going to prevent manual, unsafe casts. - Fix a typo (s/preffered/prefered/). Changes in v3: - Fix the commit message. - Remove redundant braces in `use`, when only one item is imported. Changes in v2: - Do not remove `c_str` macro. While it's preferred to use C-string literals, there are two cases where `c_str` is helpful: - When working with macros, which already return a Rust string literal (e.g. `stringify!`). - When building macros, where we want to take a Rust string literal as an argument (for caller's convenience), but still use it as a C-string internally. - Use Rust literals as arguments in macros (`new_mutex`, `new_condvar`, `new_mutex`). Use the `c_str` macro to convert these literals to C-string literals. - Use `c_str` in kunit.rs for converting the output of `stringify!` to a `CStr`. - Remove `DerefMut` implementation for `CString`. --- Tamir Duberstein (5): rust: macros: reduce collections in `quote!` macro rust: support formatting of foreign types rust: replace `CStr` with `core::ffi::CStr` rust: replace `kernel::c_str!` with C-Strings rust: remove core::ffi::CStr reexport drivers/block/rnull.rs | 4 +- drivers/cpufreq/rcpufreq_dt.rs | 5 +- drivers/gpu/drm/drm_panic_qr.rs | 5 +- drivers/gpu/drm/nova/driver.rs | 10 +- drivers/gpu/nova-core/driver.rs | 6 +- drivers/gpu/nova-core/firmware.rs | 2 +- drivers/gpu/nova-core/gpu.rs | 4 +- drivers/gpu/nova-core/nova_core.rs | 2 +- drivers/net/phy/ax88796b_rust.rs | 8 +- drivers/net/phy/qt2025.rs | 6 +- rust/kernel/auxiliary.rs | 6 +- rust/kernel/block/mq.rs | 2 +- rust/kernel/clk.rs | 9 +- rust/kernel/configfs.rs | 14 +- rust/kernel/cpufreq.rs | 6 +- rust/kernel/device.rs | 9 +- rust/kernel/devres.rs | 2 +- rust/kernel/driver.rs | 4 +- rust/kernel/drm/device.rs | 4 +- rust/kernel/drm/driver.rs | 3 +- rust/kernel/drm/ioctl.rs | 2 +- rust/kernel/error.rs | 10 +- rust/kernel/faux.rs | 5 +- rust/kernel/firmware.rs | 16 +- rust/kernel/fmt.rs | 89 +++++++ rust/kernel/kunit.rs | 21 +- rust/kernel/lib.rs | 3 +- rust/kernel/miscdevice.rs | 5 +- rust/kernel/net/phy.rs | 12 +- rust/kernel/of.rs | 5 +- rust/kernel/pci.rs | 2 +- rust/kernel/platform.rs | 6 +- rust/kernel/prelude.rs | 5 +- rust/kernel/print.rs | 4 +- rust/kernel/seq_file.rs | 6 +- rust/kernel/str.rs | 444 ++++++++++------------------------ rust/kernel/sync.rs | 7 +- rust/kernel/sync/condvar.rs | 4 +- rust/kernel/sync/lock.rs | 4 +- rust/kernel/sync/lock/global.rs | 6 +- rust/kernel/sync/poll.rs | 1 + rust/kernel/workqueue.rs | 9 +- rust/macros/fmt.rs | 99 ++++++++ rust/macros/kunit.rs | 10 +- rust/macros/lib.rs | 19 ++ rust/macros/module.rs | 2 +- rust/macros/quote.rs | 111 ++++----- samples/rust/rust_configfs.rs | 9 +- samples/rust/rust_driver_auxiliary.rs | 7 +- samples/rust/rust_driver_faux.rs | 4 +- samples/rust/rust_driver_pci.rs | 4 +- samples/rust/rust_driver_platform.rs | 4 +- samples/rust/rust_misc_device.rs | 3 +- scripts/rustdoc_test_gen.rs | 6 +- 54 files changed, 540 insertions(+), 515 deletions(-) --- base-commit: e04c78d86a9699d136910cfc0bdcf01087e3267e change-id: 20250201-cstr-core-d4b9b69120cf Best regards, -- Tamir Duberstein <tamird(a)gmail.com>

18 hours, 27 minutes

5
11
0 0

[PATCH 0/2] selftests/cgroup: better bound for cpu.max tests

by Shashank Balaji

cpu.max selftests (both the normal one and the nested one) test the working of throttling by setting up cpu.max, running a cpu hog process for a specified duration, and comparing usage_usec as reported by cpu.stat with the duration of the cpu hog: they should be far enough. Currently, this is done by using values_close, which has two problems: 1. Semantic: values_close is used with an error percentage of 95%, which one will not expect on seeing "values close". The intent it's actually going for is "values far". 2. Accuracy: the tests can pass even if usage_usec is upto around double the expected amount. That's too high of a margin for usage_usec. Overall, this patchset improves the readability and accuracy of the cpu.max tests. Signed-off-by: Shashank Balaji <shashank.mahadasyam(a)sony.com> --- Shashank Balaji (2): selftests/cgroup: rename `expected` to `duration` in cpu.max tests selftests/cgroup: better bound in cpu.max tests tools/testing/selftests/cgroup/test_cpu.c | 42 ++++++++++++++++++------------- 1 file changed, 24 insertions(+), 18 deletions(-) --- base-commit: 66701750d5565c574af42bef0b789ce0203e3071 change-id: 20250227-kselftest-cgroup-fix-cpu-max-56619928e99b Best regards, -- Shashank Balaji <shashank.mahadasyam(a)sony.com>

21 hours

1
2
0 0

[PATCH v2] selftests/mm: Add process_madvise() tests

by wang lian

This patch adds tests for the process_madvise(), focusing on verifying behavior under various conditions including valid usage and error cases. Signed-off-by: wang lian<lianux.mm(a)gmail.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Suggested-by: David Hildenbrand <david(a)redhat.com> --- Changelog v2: - Drop MADV_DONTNEED tests based on feedback - Focus solely on process_madvise() syscall - Improve error handling and structure - Add future-proof flag test - Style and comment cleanups tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/process_madv.c | 414 ++++++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 5 + 4 files changed, 421 insertions(+) create mode 100644 tools/testing/selftests/mm/process_madv.c diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftests/mm/.gitignore index 911f39d634be..a8c3be02188c 100644 --- a/tools/testing/selftests/mm/.gitignore +++ b/tools/testing/selftests/mm/.gitignore @@ -42,6 +42,7 @@ memfd_secret hugetlb_dio pkey_sighandler_tests_32 pkey_sighandler_tests_64 +process_madv soft-dirty split_huge_page_test ksm_tests diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index 2352252f3914..725612e09582 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -86,6 +86,7 @@ TEST_GEN_FILES += mseal_test TEST_GEN_FILES += on-fault-limit TEST_GEN_FILES += pagemap_ioctl TEST_GEN_FILES += pfnmap +TEST_GEN_FILES += process_madv TEST_GEN_FILES += thuge-gen TEST_GEN_FILES += transhuge-stress TEST_GEN_FILES += uffd-stress diff --git a/tools/testing/selftests/mm/process_madv.c b/tools/testing/selftests/mm/process_madv.c new file mode 100644 index 000000000000..73999c8e3570 --- /dev/null +++ b/tools/testing/selftests/mm/process_madv.c @@ -0,0 +1,414 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#define _GNU_SOURCE +#include "../kselftest_harness.h" +#include <errno.h> +#include <setjmp.h> +#include <signal.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/mman.h> +#include <sys/syscall.h> +#include <unistd.h> +#include <sched.h> +#include <sys/pidfd.h> +#include "vm_util.h" + +#include "../pidfd/pidfd.h" + +/* + * Ignore the checkpatch warning, as per the C99 standard, section 7.14.1.1: + * + * "If the signal occurs other than as the result of calling the abort or raise + * function, the behavior is undefined if the signal handler refers to any + * object with static storage duration other than by assigning a value to an + * object declared as volatile sig_atomic_t" + */ +static volatile sig_atomic_t signal_jump_set; +static sigjmp_buf signal_jmp_buf; + +/* + * Ignore the checkpatch warning, we must read from x but don't want to do + * anything with it in order to trigger a read page fault. We therefore must use + * volatile to stop the compiler from optimising this away. + */ +#define FORCE_READ(x) (*(volatile typeof(x) *)x) + +static void handle_fatal(int c) +{ + if (!signal_jump_set) + return; + + siglongjmp(signal_jmp_buf, c); +} + +FIXTURE(process_madvise) +{ + int pidfd; + int flag; +}; + +static void setup_sighandler(void) +{ + struct sigaction act = { + .sa_handler = &handle_fatal, + .sa_flags = SA_NODEFER, + }; + + sigemptyset(&act.sa_mask); + if (sigaction(SIGSEGV, &act, NULL)) + ksft_exit_fail_perror("sigaction"); +} + +static void teardown_sighandler(void) +{ + struct sigaction act = { + .sa_handler = SIG_DFL, + .sa_flags = SA_NODEFER, + }; + + sigemptyset(&act.sa_mask); + sigaction(SIGSEGV, &act, NULL); +} + +FIXTURE_SETUP(process_madvise) +{ + self->pidfd = PIDFD_SELF; + self->flag = 0; + setup_sighandler(); +}; + +FIXTURE_TEARDOWN_PARENT(process_madvise) +{ + teardown_sighandler(); +} + +static ssize_t sys_process_madvise(int pidfd, const struct iovec *iovec, + size_t vlen, int advice, unsigned int flags) +{ + return syscall(__NR_process_madvise, pidfd, iovec, vlen, advice, flags); +} + +/* + * Enable our signal catcher and try to read/write the specified buffer. The + * return value indicates whether the read/write succeeds without a fatal + * signal. + */ +static bool try_access_buf(char *ptr, bool write) +{ + bool failed; + + /* Tell signal handler to jump back here on fatal signal. */ + signal_jump_set = true; + /* If a fatal signal arose, we will jump back here and failed is set. */ + failed = sigsetjmp(signal_jmp_buf, 0) != 0; + + if (!failed) { + if (write) + *ptr = 'x'; + else + FORCE_READ(ptr); + } + + signal_jump_set = false; + return !failed; +} + +/* Try and read from a buffer, return true if no fatal signal. */ +static bool try_read_buf(char *ptr) +{ + return try_access_buf(ptr, false); +} + +TEST_F(process_madvise, basic) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + const int madvise_pages = 4; + char *map; + ssize_t ret; + struct iovec vec[madvise_pages]; + + /* + * Create a single large mapping. We will pick pages from this + * mapping to advise on. This ensures we test non-contiguous iovecs. + */ + map = mmap(NULL, pagesize * 10, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(map, MAP_FAILED); + + /* Fill the entire region with a known pattern. */ + memset(map, 'A', pagesize * 10); + + /* + * Setup the iovec to point to 4 non-contiguous pages + * within the mapping. + */ + vec[0].iov_base = &map[0 * pagesize]; + vec[0].iov_len = pagesize; + vec[1].iov_base = &map[3 * pagesize]; + vec[1].iov_len = pagesize; + vec[2].iov_base = &map[5 * pagesize]; + vec[2].iov_len = pagesize; + vec[3].iov_base = &map[8 * pagesize]; + vec[3].iov_len = pagesize; + + ret = sys_process_madvise(PIDFD_SELF, vec, madvise_pages, MADV_DONTNEED, + 0); + if (ret == -1 && errno == EPERM) + ksft_exit_skip( + "process_madvise() unsupported or permission denied, try running as root.\n"); + else if (errno == EINVAL) + ksft_exit_skip( + "process_madvise() unsupported or parameter invalid, please check arguments.\n"); + + /* The call should succeed and report the total bytes processed. */ + ASSERT_EQ(ret, madvise_pages * pagesize); + + /* Check that advised pages are now zero. */ + for (int i = 0; i < madvise_pages; i++) { + char *advised_page = (char *)vec[i].iov_base; + + /* Access should be successful (kernel provides a new page). */ + ASSERT_TRUE(try_read_buf(advised_page)); + /* Content must be 0, not 'A'. */ + ASSERT_EQ(*advised_page, 0); + } + + /* Check that an un-advised page in between is still 'A'. */ + char *unadvised_page = &map[1 * pagesize]; + + ASSERT_TRUE(try_read_buf(unadvised_page)); + ASSERT_EQ(*unadvised_page, 'A'); + + /* Cleanup. */ + ASSERT_EQ(munmap(map, pagesize * 10), 0); +} + +static long get_smaps_anon_huge_pages(pid_t pid, void *addr) +{ + char smaps_path[64]; + char *line = NULL; + unsigned long start, end; + long anon_huge_kb; + size_t len; + FILE *f; + bool in_vma; + + in_vma = false; + sprintf(smaps_path, "/proc/%d/smaps", pid); + f = fopen(smaps_path, "r"); + if (!f) + return -1; + + while (getline(&line, &len, f) != -1) { + /* Check if the line describes a VMA range */ + if (sscanf(line, "%lx-%lx", &start, &end) == 2) { + if ((unsigned long)addr >= start && + (unsigned long)addr < end) + in_vma = true; + else + in_vma = false; + continue; + } + + /* If we are in the correct VMA, look for the AnonHugePages field */ + if (in_vma && + sscanf(line, "AnonHugePages: %ld kB", &anon_huge_kb) == 1) + break; + } + + free(line); + fclose(f); + + return (anon_huge_kb > 0) ? (anon_huge_kb * 1024) : 0; +} + +/** + * TEST_F(process_madvise, remote_collapse) + * + * This test deterministically validates process_madvise() with MADV_COLLAPSE + * on a remote process, other advices are difficult to verify reliably. + * + * The test verifies that a memory region in a child process, initially + * backed by small pages, can be collapsed into a Transparent Huge Page by a + * request from the parent. The result is verified by parsing the child's + * /proc/<pid>/smaps file. + */ +TEST_F(process_madvise, remote_collapse) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + pid_t child_pid; + int pidfd; + long huge_page_size; + int pipe_info[2]; + ssize_t ret; + struct iovec vec; + + struct child_info { + pid_t pid; + void *map_addr; + } info; + + huge_page_size = default_huge_page_size(); + if (huge_page_size <= 0) + ksft_exit_skip("Could not determine a valid huge page size.\n"); + + ASSERT_EQ(pipe(pipe_info), 0); + + child_pid = fork(); + ASSERT_NE(child_pid, -1); + + if (child_pid == 0) { + char *map; + size_t map_size = 2 * huge_page_size; + + close(pipe_info[0]); + + map = mmap(NULL, map_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(map, MAP_FAILED); + + /* Fault in as small pages */ + for (size_t i = 0; i < map_size; i += pagesize) + map[i] = 'A'; + + /* Send info and pause */ + info.pid = getpid(); + info.map_addr = map; + ret = write(pipe_info[1], &info, sizeof(info)); + ASSERT_EQ(ret, sizeof(info)); + close(pipe_info[1]); + + pause(); + exit(0); + } + + close(pipe_info[1]); + + /* Receive child info */ + ret = read(pipe_info[0], &info, sizeof(info)); + if (ret <= 0) { + waitpid(child_pid, NULL, 0); + ksft_exit_skip("Failed to read child info from pipe.\n"); + } + ASSERT_EQ(ret, sizeof(info)); + close(pipe_info[0]); + child_pid = info.pid; + + pidfd = pidfd_open(child_pid, 0); + ASSERT_GE(pidfd, 0); + + /* Baseline Check from Parent's perspective */ + ASSERT_EQ(get_smaps_anon_huge_pages(child_pid, info.map_addr), 0); + + vec.iov_base = info.map_addr; + vec.iov_len = huge_page_size; + ret = sys_process_madvise(pidfd, &vec, 1, MADV_COLLAPSE, 0); + if (ret == -1) { + if (errno == EINVAL) + ksft_exit_skip( + "PROCESS_MADV_ADVISE is not supported.\n"); + else if (errno == EPERM) + ksft_exit_skip( + "No process_madvise() permissions, try running as root.\n"); + goto cleanup; + } + ASSERT_EQ(ret, huge_page_size); + + ASSERT_EQ(get_smaps_anon_huge_pages(child_pid, info.map_addr), + huge_page_size); + + ksft_test_result_pass( + "MADV_COLLAPSE successfully verified via smaps.\n"); + +cleanup: + /* Cleanup */ + kill(child_pid, SIGKILL); + waitpid(child_pid, NULL, 0); + if (pidfd >= 0) + close(pidfd); +} + +/* + * Test process_madvise() with various invalid pidfds to ensure correct error + * handling. This includes negative fds, non-pidfd fds, and pidfds for + * processes that no longer exist. + */ +TEST_F(process_madvise, invalid_pidfd) +{ + struct iovec vec; + pid_t child_pid; + ssize_t ret; + int pidfd; + + vec.iov_base = (void *)0x1234; + vec.iov_len = 4096; + + /* Using an invalid fd number (-1) should fail with EBADF. */ + ret = sys_process_madvise(-1, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EBADF); + + /* + * Using a valid fd that is not a pidfd (e.g. stdin) should fail + * with EBADF. + */ + ret = sys_process_madvise(STDIN_FILENO, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EBADF); + + /* + * Using a pidfd for a process that has already exited should fail + * with ESRCH. + */ + child_pid = fork(); + ASSERT_NE(child_pid, -1); + + if (child_pid == 0) + exit(0); + + pidfd = pidfd_open(child_pid, 0); + ASSERT_GE(pidfd, 0); + + /* Wait for the child to ensure it has terminated. */ + waitpid(child_pid, NULL, 0); + + ret = sys_process_madvise(pidfd, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ESRCH); + close(pidfd); +} + +/* + * Test process_madvise() with an invalid flag value. Now we only support flag=0 + * future we will use it support sync so reserve this test. + */ +TEST_F(process_madvise, flag) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + unsigned int invalid_flag; + struct iovec vec; + char *map; + ssize_t ret; + + map = mmap(NULL, pagesize, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, + 0); + ASSERT_NE(map, MAP_FAILED); + + vec.iov_base = map; + vec.iov_len = pagesize; + + invalid_flag = 0x80000000; + + ret = sys_process_madvise(PIDFD_SELF, &vec, 1, MADV_DONTNEED, + invalid_flag); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EINVAL); + + /* Cleanup. */ + ASSERT_EQ(munmap(map, pagesize), 0); +} + +TEST_HARNESS_MAIN \ No newline at end of file diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index f96d43153fc0..5c28ebcf1ea9 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -61,6 +61,8 @@ separated by spaces: ksm tests that require >=2 NUMA nodes - pkey memory protection key tests +- process_madvise + test process_madvise - soft_dirty test soft dirty page bit semantics - pagemap @@ -424,6 +426,9 @@ CATEGORY="hmm" run_test bash ./test_hmm.sh smoke # MADV_GUARD_INSTALL and MADV_GUARD_REMOVE tests CATEGORY="madv_guard" run_test ./guard-regions +# PROCESS_MADVISE TEST +CATEGORY="process_madv" run_test ./process_madv + # MADV_DONTNEED and PROCESS_DONTNEED tests CATEGORY="madv_dontneed" run_test ./madv_dontneed -- 2.43.0

21 hours, 55 minutes

3
3
0 0

[PATCH v3 0/7] Add support for FEAT_{LS64, LS64_V} and related tests

by Yicong Yang

From: Yicong Yang <yangyicong(a)hisilicon.com> Armv8.7 introduces single-copy atomic 64-byte loads and stores instructions and its variants named under FEAT_{LS64, LS64_V}. Add support for Armv8.7 FEAT_{LS64, LS64_V}: - Add identifying and enabling in the cpufeature list - Expose the support of these features to userspace through HWCAP3 and cpuinfo - Add related hwcap test - Handle the trap of unsupported memory (normal/uncacheable) access in a VM A real scenario for this feature is that the userspace driver can make use of this to implement direct WQE (workqueue entry) - a mechanism to fill WQE directly into the hardware. Picked Marc's 2 patches form [1] for handling the LS64 trap in a VM on emulated MMIO and the introduce of KVM_EXIT_ARM_LDST64B. [1] https://lore.kernel.org/linux-arm-kernel/20240815125959.2097734-1-maz@kerne… Tested with hwcap test [*]: [*] https://lore.kernel.org/linux-arm-kernel/20250331094320.35226-5-yangyicong@… On host: root@localhost:/tmp# dmesg | grep "All CPU(s) started" [ 0.504846] CPU: All CPU(s) started at EL2 root@localhost:/tmp# ./hwcap [...] # LS64 present ok 217 cpuinfo_match_LS64 ok 218 sigill_LS64 ok 219 # SKIP sigbus_LS64 # LS64_V present ok 220 cpuinfo_match_LS64_V ok 221 sigill_LS64_V ok 222 # SKIP sigbus_LS64_V # 115 skipped test(s) detected. Consider enabling relevant config options to improve coverage. # Totals: pass:107 fail:0 xfail:0 xpass:0 skip:115 error:0 On guest: root@localhost:/# dmesg | grep "All CPU(s) started" [ 0.451482] CPU: All CPU(s) started at EL1 root@localhost:/mnt# ./hwcap [...] # LS64 present ok 217 cpuinfo_match_LS64 ok 218 sigill_LS64 ok 219 # SKIP sigbus_LS64 # LS64_V present ok 220 cpuinfo_match_LS64_V ok 221 sigill_LS64_V ok 222 # SKIP sigbus_LS64_V # 115 skipped test(s) detected. Consider enabling relevant config options to improve coverage. # Totals: pass:107 fail:0 xfail:0 xpass:0 skip:115 error:0 Change since v2: - Handle the LS64 fault to userspace and allow userspace to inject LS64 fault - Reorder the patches to make KVM handling prior to feature support Link: https://lore.kernel.org/linux-arm-kernel/20250331094320.35226-1-yangyicong@… Change since v1: - Drop the support for LS64_ACCDATA - handle the DABT of unsupported memory type after checking the memory attributes Link: https://lore.kernel.org/linux-arm-kernel/20241202135504.14252-1-yangyicong@… Marc Zyngier (2): KVM: arm64: Add exit to userspace on {LD,ST}64B* outside of memslots KVM: arm64: Add documentation for KVM_EXIT_ARM_LDST64B Yicong Yang (5): KVM: arm64: Handle DABT caused by LS64* instructions on unsupported memory KVM: arm/arm64: Allow user injection of unsupported exclusive/atomic DABT arm64: Provide basic EL2 setup for FEAT_{LS64, LS64_V} usage at EL0/1 arm64: Add support for FEAT_{LS64, LS64_V} KVM: arm64: Enable FEAT_{LS64, LS64_V} in the supported guest Documentation/arch/arm64/booting.rst | 12 ++++++ Documentation/arch/arm64/elf_hwcaps.rst | 6 +++ Documentation/virt/kvm/api.rst | 43 +++++++++++++++++---- arch/arm64/include/asm/el2_setup.h | 12 +++++- arch/arm64/include/asm/esr.h | 8 ++++ arch/arm64/include/asm/hwcap.h | 2 + arch/arm64/include/asm/kvm_emulate.h | 7 ++++ arch/arm64/include/uapi/asm/hwcap.h | 2 + arch/arm64/include/uapi/asm/kvm.h | 3 +- arch/arm64/kernel/cpufeature.c | 51 +++++++++++++++++++++++++ arch/arm64/kernel/cpuinfo.c | 2 + arch/arm64/kvm/guest.c | 4 ++ arch/arm64/kvm/inject_fault.c | 29 ++++++++++++++ arch/arm64/kvm/mmio.c | 27 ++++++++++++- arch/arm64/kvm/mmu.c | 21 +++++++++- arch/arm64/tools/cpucaps | 2 + include/uapi/linux/kvm.h | 3 +- 17 files changed, 222 insertions(+), 12 deletions(-) -- 2.24.0

22 hours, 42 minutes

2
12
0 0

[RFC PATCH 0/7] platform/chrome: Add Kunit tests for protocol device drivers

by Tzung-Bi Shih

The protocol device drivers under drivers/platform/chrome/ are responsible to communicate to the ChromeOS EC (Embedded Controller). They need to pack the data in a pre-defined format and check if the EC responds accordingly. The series adds some fundamental unit tests for the protocol. It calls the .cmd_xfer() and .pkt_xfer() callbacks (which are the most crucial parts for the protocol), mocks the rest of the system, and checks if the interactions are all correct. The series isn't ready for landing. It's more like a PoC for the binary-level function redirection and its use cases. The 1st patch adds ftrace stub which is originally from [1][2]. There is no follow-up discussion about the ftrace stub. As a result, the patch is still on the mailing list. The 2nd patch adds Kunit tests for cros_ec_i2c. It relies on the ftrace stub for redirecting cros_ec_{un,}register(). The 3rd patch uses static stub instead (if ftrace stub isn't really an option). However, I'm not a big fan to change the production code (i.e. adding the prologue in cros_ec_{un,}register()) for testing. The 4th patch adds Kunit tests for cros_ec_spi. It relies on the ftrace stub for redirecting cros_ec_{un,}register() again. The 5th patch calls .probe() directly instead of forcing the driver probe needs to be synchronous. In comparison with the 4th patch, I don't think this is simpler. I'd prefer to the way in the 4th patch. After talked to Masami about the work, he suggested to use Kprobes for function redirection. The 6th patch adds kprobes stub. The 7th patch uses kprobes stub instead for cros_ec_spi. Questions: - Are we going to support ftrace stub so that tests can use it? - If ftrace stub isn't on the plate (e.g. due to too many dependencies), how about the kprobes stub? Is it something we could pursue? - (minor) I'm unsure if people would prefer 'kprobes stub' vs. 'kprobe stub'. [1]: https://kunit.dev/mocking.html#binary-level-ftrace-et-al [2]: https://lore.kernel.org/linux-kselftest/20220318021314.3225240-3-davidgow@g… Daniel Latypov (1): kunit: expose ftrace-based API for stubbing out functions during tests Tzung-Bi Shih (6): platform/chrome: kunit: cros_ec_i2c: Add tests with ftrace stub platform/chrome: kunit: cros_ec_i2c: Use static stub instead platform/chrome: kunit: cros_ec_spi: Add tests with ftrace stub platform/chrome: kunit: cros_ec_spi: Call .probe() directly kunit: Expose 'kprobes stub' API to redirect functions platform/chrome: kunit: cros_ec_spi: Use kprobes stub instead drivers/platform/chrome/Kconfig | 17 + drivers/platform/chrome/Makefile | 2 + drivers/platform/chrome/cros_ec.c | 6 + drivers/platform/chrome/cros_ec_i2c_test.c | 479 +++++++++++++++++++++ drivers/platform/chrome/cros_ec_spi_test.c | 355 +++++++++++++++ include/kunit/ftrace_stub.h | 84 ++++ include/kunit/kprobes_stub.h | 19 + kernel/trace/ftrace.c | 3 + lib/kunit/Kconfig | 18 + lib/kunit/Makefile | 8 + lib/kunit/ftrace_stub.c | 139 ++++++ lib/kunit/kprobes_stub.c | 113 +++++ lib/kunit/kunit-example-test.c | 27 +- lib/kunit/stubs_example.kunitconfig | 11 + 14 files changed, 1280 insertions(+), 1 deletion(-) create mode 100644 drivers/platform/chrome/cros_ec_i2c_test.c create mode 100644 drivers/platform/chrome/cros_ec_spi_test.c create mode 100644 include/kunit/ftrace_stub.h create mode 100644 include/kunit/kprobes_stub.h create mode 100644 lib/kunit/ftrace_stub.c create mode 100644 lib/kunit/kprobes_stub.c create mode 100644 lib/kunit/stubs_example.kunitconfig -- 2.49.0.1101.gccaa498523-goog

22 hours, 54 minutes

2
11
0 0

[PATCH v5 0/7] futex: Create set_robust_list2

by André Almeida

This patch adds a new robust_list() syscall. The current syscall can't be expanded to cover the following use case, so a new one is needed. This new syscall allows users to set multiple robust lists per process and to have either 32bit or 64bit pointers in the list. * Use case FEX-Emu[1] is an application that runs x86 and x86-64 binaries on an AArch64 Linux host. One of the tasks of FEX-Emu is to translate syscalls from one platform to another. Existing set_robust_list() can't be easily translated because of two limitations: 1) x86 apps can have 32bit pointers robust lists. For a x86-64 kernel this is not a problem, because of the compat entry point. But there's no such compat entry point for AArch64, so the kernel would do the pointer arithmetic wrongly. Is also unviable to userspace to keep track every addition/removal to the robust list and keep a 64bit version of it somewhere else to feed the kernel. Thus, the new interface has an option of telling the kernel if the list is filled with 32bit or 64bit pointers. 2) Apps can set just one robust list (in theory, x86-64 can set two if they also use the compat entry point). That means that when a x86 app asks FEX-Emu to call set_robust_list(), FEX have two options: to overwrite their own robust list pointer and make the app robust, or to ignore the app robust list and keep the emulator robust. The new interface allows for multiple robust lists per application, solving this. * Interface This is the proposed interface: long set_robust_list2(void *head, int index, unsigned int flags) `head` is the head of the userspace struct robust_list_head, just as old set_robust_list(). It needs to be a void pointer since it can point to a normal robust_list_head or a compat_robust_list_head. `flags` can be used for defining the list type: enum robust_list_type { ROBUST_LIST_32BIT, ROBUST_LIST_64BIT, }; `index` is the index in the internal robust_list's linked list (the naming starts to get confusing, I reckon). If `index == -1`, that means that user wants to set a new robust_list, and the kernel will append it in the end of the list, assign a new index and return this index to the user. If `index >= 0`, that means that user wants to re-set `*head` of an already existing list (similarly to what happens when you call set_robust_list() twice with different `*head`). If `index` is out of range, or it points to a non-existing robust_list, or if the internal list is full, an error is returned. * Implementation The implementation re-uses most of the existing robust list interface as possible. The new task_struct member `struct list_head robust_list2` is just a linked list where new lists are appended as the user requests more lists, and by futex_cleanup(), the kernel walks through the internal list feeding exit_robust_list() with the robust_list's. This implementation supports up to 10 lists (defined at ROBUST_LISTS_PER_TASK), but it was an arbitrary number for this RFC. For the described use case above, 4 should be enough, I'm not sure which should be the limit. It doesn't support list removal (should it support?). It doesn't have a proper get_robust_list2() yet as well, but I can add it in a next revision. We could also have a generic robust_list() syscall that can be used to set/get and be controlled by flags. The new interface has a `unsigned int flags` argument, making it extensible for future use cases as well. It refuses unaligned `head` addresses. It doesn't have a limit for elements in a single list (like ROBUST_LIST_LIMIT), it destroys the list as it is parsed to be safe against circular lists. * Testing This patcheset has a selftest patch that expands this one: https://lore.kernel.org/lkml/20250212131123.37431-1-andrealmeid@igalia.com/ Also, FEX-Emu added support for this interface to validate it: https://github.com/FEX-Emu/FEX/pull/3966 Feedback is very welcomed! Thanks, André [1] https://github.com/FEX-Emu/FEX Changelog: - Fixed compilation issues when CONFIG_COMPAT or CONFIG_FUTEX are not set - Rebased on top of new futex work (private hash) v4: https://lore.kernel.org/lkml/20250225183531.682556-1-andrealmeid@igalia.com/ - Refuse unaligned head pointers - Ignore ROBUST_LIST_LIMIT for lists created with this interface and make it robust against circular lists - Fix a get_robust_list() syscall bug for getting the list from another thread - Adapt selftest to use the new interface v3: https://lore.kernel.org/lkml/20241217174958.477692-1-andrealmeid@igalia.com/ - Old syscall set_robust_list() adds new head to the internal linked list of robust lists pointers, instead of having a field just for them. Remove tsk->robust_list and use only tsk->robust_list2 v2: https://lore.kernel.org/lkml/20241101162147.284993-1-andrealmeid@igalia.com/ - Added a patch to properly deal with exit_robust_list() in 64bit vs 32bit - Wired-up syscall for all archs - Added more of the cover letter to the commit message v1: https://lore.kernel.org/lkml/20241024145735.162090-1-andrealmeid@igalia.com/ --- André Almeida (7): selftests/futex: Add ASSERT_ macros selftests/futex: Create test for robust list futex: Use explicit sizes for compat_exit_robust_list futex: Create set_robust_list2 futex: Remove the limit of elements for sys_set_robust_list2 lists futex: Wire up set_robust_list2 syscall selftests: futex: Expand robust list test for the new interface arch/alpha/kernel/syscalls/syscall.tbl | 1 + arch/arm/tools/syscall.tbl | 1 + arch/m68k/kernel/syscalls/syscall.tbl | 1 + arch/microblaze/kernel/syscalls/syscall.tbl | 1 + arch/mips/kernel/syscalls/syscall_n32.tbl | 1 + arch/mips/kernel/syscalls/syscall_n64.tbl | 1 + arch/mips/kernel/syscalls/syscall_o32.tbl | 1 + arch/parisc/kernel/syscalls/syscall.tbl | 1 + arch/powerpc/kernel/syscalls/syscall.tbl | 1 + arch/s390/kernel/syscalls/syscall.tbl | 1 + arch/sh/kernel/syscalls/syscall.tbl | 1 + arch/sparc/kernel/syscalls/syscall.tbl | 1 + arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + arch/xtensa/kernel/syscalls/syscall.tbl | 1 + include/linux/compat.h | 12 +- include/linux/futex.h | 30 +- include/linux/sched.h | 5 +- include/uapi/asm-generic/unistd.h | 2 + include/uapi/linux/futex.h | 10 + kernel/futex/core.c | 156 ++++- kernel/futex/futex.h | 5 + kernel/futex/syscalls.c | 85 ++- kernel/sys_ni.c | 1 + scripts/syscall.tbl | 1 + .../testing/selftests/futex/functional/.gitignore | 1 + tools/testing/selftests/futex/functional/Makefile | 3 +- .../selftests/futex/functional/robust_list.c | 706 +++++++++++++++++++++ tools/testing/selftests/futex/include/logging.h | 38 ++ 29 files changed, 1021 insertions(+), 49 deletions(-) --- base-commit: a24cc6ce1933eade12aa2b9859de0fcd2dac2c06 change-id: 20250225-tonyk-robust_futex-60adeedac695 Best regards, -- André Almeida <andrealmeid(a)igalia.com>

1 day, 1 hour

3
17
0 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

Linux-kselftest-mirror July 2025