April 2024 - Linux-kselftest-mirror

[PATCH RFC bpf-next v6 0/6] sleepable bpf_timer (was: allow HID-BPF to do device IOs)

by Benjamin Tissoires

New version of the sleepable bpf_timer code. I'm posting this as this is the result of the previous review, so we can have a baseline to compare to. The plan is now to introduce a new user API struct bpf_wq, as the timer API working on softIRQ seems to be quite far away from a wq. For reference, the use cases I have in mind: --- Basically, I need to be able to defer a HID-BPF program for the following reasons (from the aforementioned patch): 1. defer an event: Sometimes we receive an … [View More]out of proximity event, but the device can not be trusted enough, and we need to ensure that we won't receive another one in the following n milliseconds. So we need to wait those n milliseconds, and eventually re-inject that event in the stack. 2. inject new events in reaction to one given event: We might want to transform one given event into several. This is the case for macro keys where a single key press is supposed to send a sequence of key presses. But this could also be used to patch a faulty behavior, if a device forgets to send a release event. 3. communicate with the device in reaction to one event: We might want to communicate back to the device after a given event. For example a device might send us an event saying that it came back from sleeping state and needs to be re-initialized. Currently we can achieve that by keeping a userspace program around, raise a bpf event, and let that userspace program inject the events and commands. However, we are just keeping that program alive as a daemon for just scheduling commands. There is no logic in it, so it doesn't really justify an actual userspace wakeup. So a kernel workqueue seems simpler to handle. bpf_timers are currently running in a soft IRQ context, this patch series implements a sleppable context for them. Cheers, Benjamin To: Alexei Starovoitov <ast(a)kernel.org> To: Daniel Borkmann <daniel(a)iogearbox.net> To: Andrii Nakryiko <andrii(a)kernel.org> To: Martin KaFai Lau <martin.lau(a)linux.dev> To: Eduard Zingerman <eddyz87(a)gmail.com> To: Song Liu <song(a)kernel.org> To: Yonghong Song <yonghong.song(a)linux.dev> To: John Fastabend <john.fastabend(a)gmail.com> To: KP Singh <kpsingh(a)kernel.org> To: Stanislav Fomichev <sdf(a)google.com> To: Hao Luo <haoluo(a)google.com> To: Jiri Olsa <jolsa(a)kernel.org> To: Mykola Lysenko <mykolal(a)fb.com> To: Shuah Khan <shuah(a)kernel.org> Cc: Benjamin Tissoires <bentiss(a)kernel.org> Cc: <bpf(a)vger.kernel.org> Cc: <linux-kernel(a)vger.kernel.org> Cc: <linux-kselftest(a)vger.kernel.org> --- Changes in v6: - Use of a workqueue to clean up sleepable timers - integrated Kumar's patch instead of mine - Link to v5: https://lore.kernel.org/r/20240322-hid-bpf-sleepable-v5-0-179c7b59eaaa@kern… Changes in v5: - took various reviews into account - rewrote the tests to be separated to not have a uggly include - Link to v4: https://lore.kernel.org/r/20240315-hid-bpf-sleepable-v4-0-5658f2540564@kern… Changes in v4: - dropped the HID changes, they can go independently from bpf-core - addressed Alexei's and Eduard's remarks - added selftests - Link to v3: https://lore.kernel.org/r/20240221-hid-bpf-sleepable-v3-0-1fb378ca6301@kern… Changes in v3: - fixed the crash from v2 - changed the API to have only BPF_F_TIMER_SLEEPABLE for bpf_timer_start() - split the new kfuncs/verifier patch into several sub-patches, for easier reviews - Link to v2: https://lore.kernel.org/r/20240214-hid-bpf-sleepable-v2-0-5756b054724d@kern… Changes in v2: - make use of bpf_timer (and dropped the custom HID handling) - implemented bpf_timer_set_sleepable_cb as a kfunc - still not implemented global subprogs - no sleepable bpf_timer selftests yet - Link to v1: https://lore.kernel.org/r/20240209-hid-bpf-sleepable-v1-0-4cc895b5adbd@kern… --- Benjamin Tissoires (5): bpf/helpers: introduce sleepable bpf_timers bpf/helpers: introduce bpf_timer_set_sleepable_cb() kfunc bpf/helpers: mark the callback of bpf_timer_set_sleepable_cb() as sleepable tools: sync include/uapi/linux/bpf.h selftests/bpf: add sleepable timer tests Kumar Kartikeya Dwivedi (1): bpf: Add support for KF_ARG_PTR_TO_TIMER include/linux/bpf_verifier.h | 1 + include/uapi/linux/bpf.h | 13 ++ kernel/bpf/helpers.c | 202 ++++++++++++++++--- kernel/bpf/verifier.c | 98 +++++++++- tools/include/uapi/linux/bpf.h | 20 +- tools/testing/selftests/bpf/bpf_experimental.h | 5 + .../selftests/bpf/bpf_testmod/bpf_testmod.c | 5 + .../selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h | 1 + tools/testing/selftests/bpf/prog_tests/timer.c | 34 ++++ .../testing/selftests/bpf/progs/timer_sleepable.c | 213 +++++++++++++++++++++ 10 files changed, 553 insertions(+), 39 deletions(-) --- base-commit: 61df575632d6b39213f47810c441bddbd87c3606 change-id: 20240205-hid-bpf-sleepable-c01260fd91c4 Best regards, -- Benjamin Tissoires <bentiss(a)kernel.org> [View Less]

1 year

5
20
0 0

[PATCH v3 00/30] NT synchronization primitive driver

by Elizabeth Figura

This patch series introduces a new char misc driver, /dev/ntsync, which is used to implement Windows NT synchronization primitives. == Background == The Wine project emulates the Windows API in user space. One particular part of that API, namely the NT synchronization primitives, have historically been implemented via RPC to a dedicated "kernel" process. However, more recent applications use these APIs more strenuously, and the overhead of RPC has become a bottleneck. The NT synchronization … [View More]APIs are too complex to implement on top of existing primitives without sacrificing correctness. Certain operations, such as NtPulseEvent() or the "wait-for-all" mode of NtWaitForMultipleObjects(), require direct control over the underlying wait queue, and implementing a wait queue sufficiently robust for Wine in user space is not possible. This proposed driver, therefore, implements the problematic interfaces directly in the Linux kernel. This driver was presented at Linux Plumbers Conference 2023. For those further interested in the history of synchronization in Wine and past attempts to solve this problem in user space, a recording of the presentation can be viewed here: https://www.youtube.com/watch?v=NjU4nyWyhU8 == Performance == The gain in performance varies wildly depending on the application in question and the user's hardware. For some games NT synchronization is not a bottleneck and no change can be observed, but for others frame rate improvements of 50 to 150 percent are not atypical. The following table lists frame rate measurements from a variety of games on a variety of hardware, taken by users Dmitry Skvortsov, FuzzyQuils, OnMars, and myself: Game Upstream ntsync improvement =========================================================================== Anger Foot 69 99 43% Call of Juarez 99.8 224.1 125% Dirt 3 110.6 860.7 678% Forza Horizon 5 108 160 48% Lara Croft: Temple of Osiris 141 326 131% Metro 2033 164.4 199.2 21% Resident Evil 2 26 77 196% The Crew 26 51 96% Tiny Tina's Wonderlands 130 360 177% Total War Saga: Troy 109 146 34% =========================================================================== == Patches == The intended semantics of the patches are broadly intended to match those of the corresponding Windows functions. For those not already familiar with the Windows functions (or their undocumented behaviour), patch 31/31 provides a detailed specification, and individual patches also include a brief description of the API they are implementing. The patches making use of this driver in Wine can be retrieved or browsed here: https://repo.or.cz/wine/zf.git/shortlog/refs/heads/ntsync5 == Implementation == Some aspects of the implementation may deserve particular comment: * In the interest of performance, each object is governed only by a single spinlock. However, NTSYNC_IOC_WAIT_ALL requires that the state of multiple objects be changed as a single atomic operation. In order to achieve this, we first take a device-wide lock ("wait_all_lock") any time we are going to lock more than one object at a time. The maximum number of objects that can be used in a vectored wait, and therefore the maximum that can be locked simultaneously, is 64. This number is NT's own limit. The acquisition of multiple spinlocks will degrade performance. This is a conscious choice, however. Wait-for-all is known to be a very rare operation in practice, especially with counts that approach the maximum, and it is the intent of the ntsync driver to optimize wait-for-any at the expense of wait-for-all as much as possible. * NT mutexes are tied to their threads on an OS level, and the kernel includes builtin support for "robust" mutexes. In order to keep the ntsync driver self-contained and avoid touching more code than necessary, it does not hook into task exit nor use pids. Instead, the user space emulator is expected to manage thread IDs and pass them as an argument to any relevant functions; this is the "owner" field of ntsync_wait_args and ntsync_mutex_args. When the emulator detects that a thread dies, it should therefore call NTSYNC_IOC_MUTEX_KILL on any open mutexes. * ntsync is module-capable mostly because there was nothing preventing it, and because it aided development. It is not a hard requirement, though. == Previous versions == Changes from v2: * Check the result of fget() for NULL. * Squash patch 31 (introducing the NTSYNC_WAIT_REALTIME flag) into patch 4, per Arnd Bergmann. * Use atomic_try_cmpxchg() instead of atomic_cmpxchg(), per off-list review from Uros Bizjak. * Link to v2: https://lore.kernel.org/lkml/20240219223833.95710-1-zfigura@codeweavers.com/ * Link to v1: https://lore.kernel.org/lkml/20240214233645.9273-1-zfigura@codeweavers.com/ * Link to RFC v2: https://lore.kernel.org/lkml/20240131021356.10322-1-zfigura@codeweavers.com/ * Link to RFC v1: https://lore.kernel.org/lkml/20240124004028.16826-1-zfigura@codeweavers.com/ Elizabeth Figura (30): ntsync: Introduce the ntsync driver and character device. ntsync: Introduce NTSYNC_IOC_CREATE_SEM. ntsync: Introduce NTSYNC_IOC_SEM_POST. ntsync: Introduce NTSYNC_IOC_WAIT_ANY. ntsync: Introduce NTSYNC_IOC_WAIT_ALL. ntsync: Introduce NTSYNC_IOC_CREATE_MUTEX. ntsync: Introduce NTSYNC_IOC_MUTEX_UNLOCK. ntsync: Introduce NTSYNC_IOC_MUTEX_KILL. ntsync: Introduce NTSYNC_IOC_CREATE_EVENT. ntsync: Introduce NTSYNC_IOC_EVENT_SET. ntsync: Introduce NTSYNC_IOC_EVENT_RESET. ntsync: Introduce NTSYNC_IOC_EVENT_PULSE. ntsync: Introduce NTSYNC_IOC_SEM_READ. ntsync: Introduce NTSYNC_IOC_MUTEX_READ. ntsync: Introduce NTSYNC_IOC_EVENT_READ. ntsync: Introduce alertable waits. selftests: ntsync: Add some tests for semaphore state. selftests: ntsync: Add some tests for mutex state. selftests: ntsync: Add some tests for NTSYNC_IOC_WAIT_ANY. selftests: ntsync: Add some tests for NTSYNC_IOC_WAIT_ALL. selftests: ntsync: Add some tests for wakeup signaling with WINESYNC_IOC_WAIT_ANY. selftests: ntsync: Add some tests for wakeup signaling with WINESYNC_IOC_WAIT_ALL. selftests: ntsync: Add some tests for manual-reset event state. selftests: ntsync: Add some tests for auto-reset event state. selftests: ntsync: Add some tests for wakeup signaling with events. selftests: ntsync: Add tests for alertable waits. selftests: ntsync: Add some tests for wakeup signaling via alerts. selftests: ntsync: Add a stress test for contended waits. maintainers: Add an entry for ntsync. docs: ntsync: Add documentation for the ntsync uAPI. Documentation/userspace-api/index.rst | 1 + .../userspace-api/ioctl/ioctl-number.rst | 2 + Documentation/userspace-api/ntsync.rst | 399 +++++ MAINTAINERS | 9 + drivers/misc/Kconfig | 11 + drivers/misc/Makefile | 1 + drivers/misc/ntsync.c | 1166 ++++++++++++++ include/uapi/linux/ntsync.h | 62 + tools/testing/selftests/Makefile | 1 + .../testing/selftests/drivers/ntsync/Makefile | 8 + tools/testing/selftests/drivers/ntsync/config | 1 + .../testing/selftests/drivers/ntsync/ntsync.c | 1407 +++++++++++++++++ 12 files changed, 3068 insertions(+) create mode 100644 Documentation/userspace-api/ntsync.rst create mode 100644 drivers/misc/ntsync.c create mode 100644 include/uapi/linux/ntsync.h create mode 100644 tools/testing/selftests/drivers/ntsync/Makefile create mode 100644 tools/testing/selftests/drivers/ntsync/config create mode 100644 tools/testing/selftests/drivers/ntsync/ntsync.c base-commit: 4cece764965020c22cff7665b18a012006359095 -- 2.43.0 [View Less]

1 year

4
36
0 0

[PATCH v6 7/7] selftest/bpf: Test a perf bpf program that suppresses side effects.

by Kyle Huey

The test sets a hardware breakpoint and uses a bpf program to suppress the side effects of a perf event sample, including I/O availability signals, SIGTRAPs, and decrementing the event counter limit, if the ip matches the expected value. Then the function with the breakpoint is executed multiple times to test that all effects behave as expected. Signed-off-by: Kyle Huey <khuey(a)kylehuey.com> Acked-by: Song Liu <song(a)kernel.org> Acked-by: Jiri Olsa <jolsa(a)kernel.org> … [View More]Acked-by: Andrii Nakryiko <andrii(a)kernel.org> --- .../selftests/bpf/prog_tests/perf_skip.c | 137 ++++++++++++++++++ .../selftests/bpf/progs/test_perf_skip.c | 15 ++ 2 files changed, 152 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_skip.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_skip.c diff --git a/tools/testing/selftests/bpf/prog_tests/perf_skip.c b/tools/testing/selftests/bpf/prog_tests/perf_skip.c new file mode 100644 index 000000000000..37d8618800e4 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_skip.c @@ -0,0 +1,137 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE + +#include <test_progs.h> +#include "test_perf_skip.skel.h" +#include <linux/compiler.h> +#include <linux/hw_breakpoint.h> +#include <sys/mman.h> + +#ifndef TRAP_PERF +#define TRAP_PERF 6 +#endif + +int sigio_count, sigtrap_count; + +static void handle_sigio(int sig __always_unused) +{ + ++sigio_count; +} + +static void handle_sigtrap(int signum __always_unused, + siginfo_t *info, + void *ucontext __always_unused) +{ + ASSERT_EQ(info->si_code, TRAP_PERF, "si_code"); + ++sigtrap_count; +} + +static noinline int test_function(void) +{ + asm volatile (""); + return 0; +} + +void serial_test_perf_skip(void) +{ + struct sigaction action = {}; + struct sigaction previous_sigtrap; + sighandler_t previous_sigio = SIG_ERR; + struct test_perf_skip *skel = NULL; + struct perf_event_attr attr = {}; + int perf_fd = -1; + int err; + struct f_owner_ex owner; + struct bpf_link *prog_link = NULL; + + action.sa_flags = SA_SIGINFO | SA_NODEFER; + action.sa_sigaction = handle_sigtrap; + sigemptyset(&action.sa_mask); + if (!ASSERT_OK(sigaction(SIGTRAP, &action, &previous_sigtrap), "sigaction")) + return; + + previous_sigio = signal(SIGIO, handle_sigio); + if (!ASSERT_NEQ(previous_sigio, SIG_ERR, "signal")) + goto cleanup; + + skel = test_perf_skip__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_load")) + goto cleanup; + + attr.type = PERF_TYPE_BREAKPOINT; + attr.size = sizeof(attr); + attr.bp_type = HW_BREAKPOINT_X; + attr.bp_addr = (uintptr_t)test_function; + attr.bp_len = sizeof(long); + attr.sample_period = 1; + attr.sample_type = PERF_SAMPLE_IP; + attr.pinned = 1; + attr.exclude_kernel = 1; + attr.exclude_hv = 1; + attr.precise_ip = 3; + attr.sigtrap = 1; + attr.remove_on_exec = 1; + + perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); + if (perf_fd < 0 && (errno == ENOENT || errno == EOPNOTSUPP)) { + printf("SKIP:no PERF_TYPE_BREAKPOINT/HW_BREAKPOINT_X\n"); + test__skip(); + goto cleanup; + } + if (!ASSERT_OK(perf_fd < 0, "perf_event_open")) + goto cleanup; + + /* Configure the perf event to signal on sample. */ + err = fcntl(perf_fd, F_SETFL, O_ASYNC); + if (!ASSERT_OK(err, "fcntl(F_SETFL, O_ASYNC)")) + goto cleanup; + + owner.type = F_OWNER_TID; + owner.pid = syscall(__NR_gettid); + err = fcntl(perf_fd, F_SETOWN_EX, &owner); + if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)")) + goto cleanup; + + /* Allow at most one sample. A sample rejected by bpf should + * not count against this. + */ + err = ioctl(perf_fd, PERF_EVENT_IOC_REFRESH, 1); + if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_REFRESH)")) + goto cleanup; + + prog_link = bpf_program__attach_perf_event(skel->progs.handler, perf_fd); + if (!ASSERT_OK_PTR(prog_link, "bpf_program__attach_perf_event")) + goto cleanup; + + /* Configure the bpf program to suppress the sample. */ + skel->bss->ip = (uintptr_t)test_function; + test_function(); + + ASSERT_EQ(sigio_count, 0, "sigio_count"); + ASSERT_EQ(sigtrap_count, 0, "sigtrap_count"); + + /* Configure the bpf program to allow the sample. */ + skel->bss->ip = 0; + test_function(); + + ASSERT_EQ(sigio_count, 1, "sigio_count"); + ASSERT_EQ(sigtrap_count, 1, "sigtrap_count"); + + /* Test that the sample above is the only one allowed (by perf, not + * by bpf) + */ + test_function(); + + ASSERT_EQ(sigio_count, 1, "sigio_count"); + ASSERT_EQ(sigtrap_count, 1, "sigtrap_count"); + +cleanup: + bpf_link__destroy(prog_link); + if (perf_fd >= 0) + close(perf_fd); + test_perf_skip__destroy(skel); + + if (previous_sigio != SIG_ERR) + signal(SIGIO, previous_sigio); + sigaction(SIGTRAP, &previous_sigtrap, NULL); +} diff --git a/tools/testing/selftests/bpf/progs/test_perf_skip.c b/tools/testing/selftests/bpf/progs/test_perf_skip.c new file mode 100644 index 000000000000..7eb8b6de7a57 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_skip.c @@ -0,0 +1,15 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +uintptr_t ip; + +SEC("perf_event") +int handler(struct bpf_perf_event_data *data) +{ + /* Skip events that have the correct ip. */ + return ip != PT_REGS_IP(&data->regs); +} + +char _license[] SEC("license") = "GPL"; -- 2.34.1 [View Less]

1 year

1
0
0 0

kselftest/next build: 2 builds: 0 failed, 2 passed, 1 warning (v6.9-rc2-20-g4f4ade6863ce)

by kernelci.org bot

kselftest/next build: 2 builds: 0 failed, 2 passed, 1 warning (v6.9-rc2-20-g4f4ade6863ce) Full Build Summary: https://kernelci.org/build/kselftest/branch/next/kernel/v6.9-rc2-20-g4f4ade… Tree: kselftest Branch: next Git Describe: v6.9-rc2-20-g4f4ade6863ce Git Commit: 4f4ade6863ced470fd33152dcf8ba8ae2534d8e2 Git URL: https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git Built: 2 unique architectures Warnings Detected: arm64: x86_64: x86_64_defconfig+kselftest (clang-… [View More]

1 year

1
0
0 0

[PATCH 1/3] selftests: timers: Fix posix_timers ksft_print_msg warning

by John Stultz

After commit 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()") I started seeing the following warning building with an older gcc: posix_timers.c:250:2: warning: format not a string literal and no format arguments [-Wformat-security] 250 | ksft_print_msg(errmsg); | ^~~~~~~~~~~~~~ Fix this up by changing it to ksft_print_msg("%s", errmsg) Cc: Shuah Khan <shuah(a)kernel.org> Cc: Anna-Maria Behnsen <anna-maria(a)linutronix.de> Cc: … [View More]

1 year

5
10
0 0

[PATCH] selftests/clone3: Fix compiler warning

by Mark Brown

Shuah reported a compiler warning with an Ubuntu GCC 13 build, I've been unable to reproduce it but hopefully this fixes the issue: clone3_set_tid.c:136:43: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘size_t’ {aka ‘long unsigned int’} [-Wformat=] Reported-by: Shuah Khan <skhan(a)linuxfoundation.org> Signed-off-by: Mark Brown <broonie(a)kernel.org> --- tools/testing/selftests/clone3/clone3_set_tid.c | 2 +- 1 file changed, 1 insertion(+), 1 … [View More]

1 year

2
1
0 0

[PATCH] selftests/clone3: Correct log message for waitpid() failures

by Mark Brown

When logging an error from calling waitpid() on the child we print a misleading error message saying that the error we report was returned by the chilld. Fix this to say the error is from waitpid(). Signed-off-by: Mark Brown <broonie(a)kernel.org> --- tools/testing/selftests/clone3/clone3.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c index 3c9bf0cd82a8..eb108727c35c 100644 --- a/… [View More]

1 year

2
1
0 0

[PATCH] selftests/clone3: Check that the child exited cleanly

by Mark Brown

When the child exits during the clone3() selftest we use WEXITSTATUS() to get the exit status from the process without first checking WIFEXITED() to see if the result will be valid. This can lead to incorrect results, for example if the child exits due to signal. Add a WIFEXTED() check and report any non-standard exit as a failure, using EXIT_FAILURE as the exit status for call_clone3() since we otherwise report 0 or negative errnos. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- … [View More]

1 year

2
1
0 0

[PATCH bpf-next v5 0/2] export send_recv_data

by Geliang Tang

From: Geliang Tang <tanggeliang(a)kylinos.cn> v5: - address Martin's comments for v4 (thanks). - update patch 2, use 'return err' instead of 'return -1/0'. - drop patch 3 in v4. v4: - fix a bug in v3, it should be 'if (err)', not 'if (!err)'. - move "selftests/bpf: Use log_err in network_helpers" out of this series. v3: - add two more patches. - use log_err instead of ASSERT in v3. - let send_recv_data return int as Martin suggested. v2: Address Martin's comments for v1 (… [View More]

1 year

3
4
0 0

[PATCH net-next v2 0/2] mptcp: add last time fields in mptcp_info

by Matthieu Baerts (NGI0)

These patches from Geliang add support for the "last time" field in MPTCP Info, and verify that the counters look valid. Patch 1 adds these counters: last_data_sent, last_data_recv and last_ack_recv. They are available in the MPTCP Info, so exposed via getsockopt(MPTCP_INFO) and the Netlink Diag interface. Patch 2 adds a test in diag.sh MPTCP selftest, to check that the counters have moved by at least 250ms, after having waited twice that time. Signed-off-by: Matthieu Baerts (NGI0) <… [View More]

1 year

4
7
0 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

Linux-kselftest-mirror April 2024