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[PATCH v2] selftests/tty: add TIOCSTI test suite

by Abhinav Saxena via B4 Relay

From: Abhinav Saxena <xandfury(a)gmail.com> TIOCSTI is a TTY ioctl command that allows inserting characters into the terminal input queue, making it appear as if the user typed those characters. Add a test suite with four tests to verify TIOCSTI behaviour in different scenarios when dev.tty.legacy_tiocsti is both enabled and disabled: - Test TIOCSTI functionality when legacy support is enabled - Test TIOCSTI rejection when legacy support is disabled - Test capability requirements for TIOCSTI usage - Test TIOCSTI security with file descriptor passing The tests validate proper enforcement of the legacy_tiocsti sysctl introduced in commit 83efeeeb3d04 ("tty: Allow TIOCSTI to be disabled"). See tty_ioctl(4) for details on TIOCSTI behavior and security requirements. Signed-off-by: Abhinav Saxena <xandfury(a)gmail.com> --- This patch adds comprehensive selftests for the TIOCSTI ioctl to validate proper behaviour under different system configurations. =============== The TIOCSTI ioctl allows inserting characters into the terminal input queue, making it appear as if the user typed those characters. This functionality has security implications and behaviour that varies based on system configuration. Background ========== CONFIG_LEGACY_TIOCSTI controls the default value for the dev.tty.legacy_tiocsti sysctl, which remains runtime-configurable. The dev.tty.legacy_tiocsti sysctl was introduced in commit 83efeeeb3d04 ("tty: Allow TIOCSTI to be disabled") to provide administrators control over TIOCSTI usage. When legacy_tiocsti is disabled, TIOCSTI requires CAP_SYS_ADMIN capability. However, the current implementation only checks the current process's credentials via capable(CAP_SYS_ADMIN), which doesn't validate against the file opener's credentials stored in file->f_cred. This creates a potential security scenario where an unprivileged process can open a TTY fd and pass it to a privileged process via SCM_RIGHTS. Testing ======= The test suite includes four comprehensive tests: - Test TIOCSTI functionality when legacy support is enabled - Test TIOCSTI rejection when legacy support is disabled - Test capability requirements for TIOCSTI usage - Test TIOCSTI security with file descriptor passing All patches have been validated using: - scripts/checkpatch.pl --strict (0 errors, 0 warnings) - Functional testing on kernel v6.16-rc2 - File descriptor passing security test scenarios The fd_passing_security test demonstrates the security concern. To verify, disable legacy TIOCSTI and run the test: $ echo "0" | sudo tee /proc/sys/dev/tty/legacy_tiocsti $ sudo ./tools/testing/selftests/tty/tty_tiocsti_test -t fd_passing_security Patch Overview ============== PATCH 1/1: selftests/tty: add TIOCSTI test suite Comprehensive test suite demonstrating the issue and fix validation References ========== - tty_ioctl(4) - documents TIOCSTI ioctl and capability requirements - commit 83efeeeb3d04 ("tty: Allow TIOCSTI to be disabled") - Documentation/security/credentials.rst - https://github.com/KSPP/linux/issues/156 - https://lore.kernel.org/linux-hardening/Y0m9l52AKmw6Yxi1@hostpad/ - drivers/tty/Kconfig Configuration References: [1] - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/dri… [2] - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/dri… [3] - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/dri… Signed-off-by: Abhinav Saxena <xandfury(a)gmail.com> Changes in v2: - Focused series on selftests only - Removed SELinux capability checking patch for separate submission - Link to v1: https://lore.kernel.org/r/20250622-toicsti-bug-v1-0-f374373b04b2@gmail.com --- tools/testing/selftests/tty/Makefile | 6 +- tools/testing/selftests/tty/config | 1 + tools/testing/selftests/tty/tty_tiocsti_test.c | 421 +++++++++++++++++++++++++ 3 files changed, 427 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/tty/Makefile b/tools/testing/selftests/tty/Makefile index 50d7027b2ae3..7f6fbe5a0cd5 100644 --- a/tools/testing/selftests/tty/Makefile +++ b/tools/testing/selftests/tty/Makefile @@ -1,5 +1,9 @@ # SPDX-License-Identifier: GPL-2.0 CFLAGS = -O2 -Wall -TEST_GEN_PROGS := tty_tstamp_update +TEST_GEN_PROGS := tty_tstamp_update tty_tiocsti_test +LDLIBS += -lcap include ../lib.mk + +# Add libcap for TIOCSTI test +$(OUTPUT)/tty_tiocsti_test: LDLIBS += -lcap diff --git a/tools/testing/selftests/tty/config b/tools/testing/selftests/tty/config new file mode 100644 index 000000000000..c6373aba6636 --- /dev/null +++ b/tools/testing/selftests/tty/config @@ -0,0 +1 @@ +CONFIG_LEGACY_TIOCSTI=y diff --git a/tools/testing/selftests/tty/tty_tiocsti_test.c b/tools/testing/selftests/tty/tty_tiocsti_test.c new file mode 100644 index 000000000000..6a4b497078b0 --- /dev/null +++ b/tools/testing/selftests/tty/tty_tiocsti_test.c @@ -0,0 +1,421 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * TTY Tests - TIOCSTI + * + * Copyright © 2025 Abhinav Saxena <xandfury(a)gmail.com> + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/ioctl.h> +#include <errno.h> +#include <stdbool.h> +#include <string.h> +#include <sys/socket.h> +#include <sys/wait.h> +#include <pwd.h> +#include <termios.h> +#include <grp.h> +#include <sys/capability.h> +#include <sys/prctl.h> + +#include "../kselftest_harness.h" + +/* Helper function to send FD via SCM_RIGHTS */ +static int send_fd_via_socket(int socket_fd, int fd_to_send) +{ + struct msghdr msg = { 0 }; + struct cmsghdr *cmsg; + char cmsg_buf[CMSG_SPACE(sizeof(int))]; + char dummy_data = 'F'; + struct iovec iov = { .iov_base = &dummy_data, .iov_len = 1 }; + + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = cmsg_buf; + msg.msg_controllen = sizeof(cmsg_buf); + + cmsg = CMSG_FIRSTHDR(&msg); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + cmsg->cmsg_len = CMSG_LEN(sizeof(int)); + + memcpy(CMSG_DATA(cmsg), &fd_to_send, sizeof(int)); + + return sendmsg(socket_fd, &msg, 0) < 0 ? -1 : 0; +} + +/* Helper function to receive FD via SCM_RIGHTS */ +static int recv_fd_via_socket(int socket_fd) +{ + struct msghdr msg = { 0 }; + struct cmsghdr *cmsg; + char cmsg_buf[CMSG_SPACE(sizeof(int))]; + char dummy_data; + struct iovec iov = { .iov_base = &dummy_data, .iov_len = 1 }; + int received_fd = -1; + + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = cmsg_buf; + msg.msg_controllen = sizeof(cmsg_buf); + + if (recvmsg(socket_fd, &msg, 0) < 0) + return -1; + + for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { + if (cmsg->cmsg_level == SOL_SOCKET && + cmsg->cmsg_type == SCM_RIGHTS) { + memcpy(&received_fd, CMSG_DATA(cmsg), sizeof(int)); + break; + } + } + + return received_fd; +} + +static inline bool has_cap_sys_admin(void) +{ + cap_t caps = cap_get_proc(); + + if (!caps) + return false; + + cap_flag_value_t cap_val; + bool has_cap = (cap_get_flag(caps, CAP_SYS_ADMIN, CAP_EFFECTIVE, + &cap_val) == 0) && + (cap_val == CAP_SET); + + cap_free(caps); + return has_cap; +} + +/* + * Simple privilege drop that just changes uid/gid in current process + * and also capabilities like CAP_SYS_ADMIN + */ +static inline bool drop_to_nobody(void) +{ + /* Drop supplementary groups */ + if (setgroups(0, NULL) != 0) { + printf("setgroups failed: %s", strerror(errno)); + return false; + } + + /* Change group to nobody */ + if (setgid(65534) != 0) { + printf("setgid failed: %s", strerror(errno)); + return false; + } + + /* Change user to nobody (this drops capabilities) */ + if (setuid(65534) != 0) { + printf("setuid failed: %s", strerror(errno)); + return false; + } + + /* Verify we no longer have CAP_SYS_ADMIN */ + if (has_cap_sys_admin()) { + printf("ERROR: Still have CAP_SYS_ADMIN after changing to nobody"); + return false; + } + + printf("Successfully changed to nobody (uid:%d gid:%d)\n", getuid(), + getgid()); + return true; +} + +static inline int get_legacy_tiocsti_setting(void) +{ + FILE *fp; + int value = -1; + + fp = fopen("/proc/sys/dev/tty/legacy_tiocsti", "r"); + if (!fp) { + if (errno == ENOENT) { + printf("legacy_tiocsti sysctl not available (kernel < 6.2)\n"); + } else { + printf("Cannot read legacy_tiocsti: %s\n", + strerror(errno)); + } + return -1; + } + + if (fscanf(fp, "%d", &value) == 1) { + printf("legacy_tiocsti setting=%d\n", value); + + if (value < 0 || value > 1) { + printf("legacy_tiocsti unexpected value %d\n", value); + value = -1; + } else { + printf("legacy_tiocsti=%d (%s mode)\n", value, + value == 0 ? "restricted" : "permissive"); + } + } else { + printf("Failed to parse legacy_tiocsti value"); + value = -1; + } + + fclose(fp); + return value; +} + +static inline int test_tiocsti_injection(int fd) +{ + int ret; + char test_char = 'X'; + + ret = ioctl(fd, TIOCSTI, &test_char); + if (ret == 0) { + /* Clear the injected character */ + printf("TIOCSTI injection succeeded\n"); + } else { + printf("TIOCSTI injection failed: %s (errno=%d)\n", + strerror(errno), errno); + } + return ret == 0 ? 0 : -1; +} + +FIXTURE(tty_tiocsti) +{ + int tty_fd; + char *tty_name; + bool has_tty; + bool initial_cap_sys_admin; + int legacy_tiocsti_setting; +}; + +FIXTURE_SETUP(tty_tiocsti) +{ + TH_LOG("Running as UID: %d with effective UID: %d", getuid(), + geteuid()); + + self->tty_fd = open("/dev/tty", O_RDWR); + self->has_tty = (self->tty_fd >= 0); + + if (self->tty_fd < 0) + TH_LOG("Cannot open /dev/tty: %s", strerror(errno)); + + self->tty_name = ttyname(STDIN_FILENO); + TH_LOG("Current TTY: %s", self->tty_name ? self->tty_name : "none"); + + self->initial_cap_sys_admin = has_cap_sys_admin(); + TH_LOG("Initial CAP_SYS_ADMIN: %s", + self->initial_cap_sys_admin ? "yes" : "no"); + + self->legacy_tiocsti_setting = get_legacy_tiocsti_setting(); +} + +FIXTURE_TEARDOWN(tty_tiocsti) +{ + if (self->has_tty && self->tty_fd >= 0) + close(self->tty_fd); +} + +/* Test case 1: legacy_tiocsti != 0 (permissive mode) */ +TEST_F(tty_tiocsti, permissive_mode) +{ + // clang-format off + if (self->legacy_tiocsti_setting < 0) + SKIP(return, + "legacy_tiocsti sysctl not available (kernel < 6.2)"); + + if (self->legacy_tiocsti_setting == 0) + SKIP(return, + "Test requires permissive mode (legacy_tiocsti=1)"); + // clang-format on + + ASSERT_TRUE(self->has_tty); + + if (self->initial_cap_sys_admin) { + ASSERT_TRUE(drop_to_nobody()); + ASSERT_FALSE(has_cap_sys_admin()); + } + + /* In permissive mode, TIOCSTI should work without CAP_SYS_ADMIN */ + EXPECT_EQ(test_tiocsti_injection(self->tty_fd), 0) + { + TH_LOG("TIOCSTI should succeed in permissive mode without CAP_SYS_ADMIN"); + } +} + +/* Test case 2: legacy_tiocsti == 0, without CAP_SYS_ADMIN (should fail) */ +TEST_F(tty_tiocsti, restricted_mode_nopriv) +{ + // clang-format off + if (self->legacy_tiocsti_setting < 0) + SKIP(return, + "legacy_tiocsti sysctl not available (kernel < 6.2)"); + + if (self->legacy_tiocsti_setting != 0) + SKIP(return, + "Test requires restricted mode (legacy_tiocsti=0)"); + // clang-format on + + ASSERT_TRUE(self->has_tty); + + if (self->initial_cap_sys_admin) { + ASSERT_TRUE(drop_to_nobody()); + ASSERT_FALSE(has_cap_sys_admin()); + } + /* In restricted mode, TIOCSTI should fail without CAP_SYS_ADMIN */ + EXPECT_EQ(test_tiocsti_injection(self->tty_fd), -1); + + /* + * it might fail with either EPERM or EIO + * EXPECT_TRUE(errno == EPERM || errno == EIO) + * { + * TH_LOG("Expected EPERM, got: %s", strerror(errno)); + * } + */ +} + +/* Test case 3: legacy_tiocsti == 0, with CAP_SYS_ADMIN (should succeed) */ +TEST_F(tty_tiocsti, restricted_mode_priv) +{ + // clang-format off + if (self->legacy_tiocsti_setting < 0) + SKIP(return, + "legacy_tiocsti sysctl not available (kernel < 6.2)"); + + if (self->legacy_tiocsti_setting != 0) + SKIP(return, + "Test requires restricted mode (legacy_tiocsti=0)"); + // clang-format on + + /* Must have CAP_SYS_ADMIN for this test */ + if (!self->initial_cap_sys_admin) + SKIP(return, "Test requires CAP_SYS_ADMIN"); + + ASSERT_TRUE(self->has_tty); + ASSERT_TRUE(has_cap_sys_admin()); + + /* In restricted mode, TIOCSTI should succeed with CAP_SYS_ADMIN */ + EXPECT_EQ(test_tiocsti_injection(self->tty_fd), 0) + { + TH_LOG("TIOCSTI should succeed in restricted mode with CAP_SYS_ADMIN"); + } +} + +/* Test TIOCSTI security with file descriptor passing */ +TEST_F(tty_tiocsti, fd_passing_security) +{ + // clang-format off + if (self->legacy_tiocsti_setting < 0) + SKIP(return, + "legacy_tiocsti sysctl not available (kernel < 6.2)"); + + if (self->legacy_tiocsti_setting != 0) + SKIP(return, + "Test requires restricted mode (legacy_tiocsti=0)"); + // clang-format on + + /* Must start with CAP_SYS_ADMIN */ + if (!self->initial_cap_sys_admin) + SKIP(return, "Test requires initial CAP_SYS_ADMIN"); + + int sockpair[2]; + pid_t child_pid; + + ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sockpair), 0); + + child_pid = fork(); + ASSERT_GE(child_pid, 0) + TH_LOG("Fork failed: %s", strerror(errno)); + + if (child_pid == 0) { + /* Child process - become unprivileged, open TTY, send FD to parent */ + close(sockpair[0]); + + TH_LOG("Child: Dropping privileges..."); + + /* Drop to nobody user (loses all capabilities) */ + drop_to_nobody(); + + /* Verify we no longer have CAP_SYS_ADMIN */ + if (has_cap_sys_admin()) { + TH_LOG("Child: Failed to drop CAP_SYS_ADMIN"); + _exit(1); + } + + TH_LOG("Child: Opening TTY as unprivileged user..."); + + int unprivileged_tty_fd = open("/dev/tty", O_RDWR); + + if (unprivileged_tty_fd < 0) { + TH_LOG("Child: Cannot open TTY: %s", strerror(errno)); + _exit(1); + } + + /* Test that we can't use TIOCSTI directly (should fail) */ + + char test_char = 'X'; + + if (ioctl(unprivileged_tty_fd, TIOCSTI, &test_char) == 0) { + TH_LOG("Child: ERROR - Direct TIOCSTI succeeded unexpectedly!"); + close(unprivileged_tty_fd); + _exit(1); + } + TH_LOG("Child: Good - Direct TIOCSTI failed as expected: %s", + strerror(errno)); + + /* Send the TTY FD to privileged parent via SCM_RIGHTS */ + TH_LOG("Child: Sending TTY FD to privileged parent..."); + if (send_fd_via_socket(sockpair[1], unprivileged_tty_fd) != 0) { + TH_LOG("Child: Failed to send FD"); + close(unprivileged_tty_fd); + _exit(1); + } + + close(unprivileged_tty_fd); + close(sockpair[1]); + _exit(0); /* Child success */ + + } else { + /* Parent process - keep CAP_SYS_ADMIN, receive FD, test TIOCSTI */ + close(sockpair[1]); + + TH_LOG("Parent: Waiting for TTY FD from unprivileged child..."); + + /* Verify we still have CAP_SYS_ADMIN */ + ASSERT_TRUE(has_cap_sys_admin()); + + /* Receive the TTY FD from unprivileged child */ + int received_fd = recv_fd_via_socket(sockpair[0]); + + ASSERT_GE(received_fd, 0) + TH_LOG("Parent: Received FD %d (opened by unprivileged process)", + received_fd); + + /* + * VULNERABILITY TEST: Try TIOCSTI with FD opened by unprivileged process + * This should FAIL even though parent has CAP_SYS_ADMIN + * because the FD was opened by unprivileged process + */ + char attack_char = 'V'; /* V for Vulnerability */ + int ret = ioctl(received_fd, TIOCSTI, &attack_char); + + TH_LOG("Parent: Testing TIOCSTI on FD from unprivileged process..."); + if (ret == 0) { + TH_LOG("*** VULNERABILITY DETECTED ***"); + TH_LOG("Privileged process can use TIOCSTI on unprivileged FD"); + } else { + TH_LOG("TIOCSTI failed on unprivileged FD: %s", + strerror(errno)); + EXPECT_EQ(errno, EPERM); + } + close(received_fd); + close(sockpair[0]); + + /* Wait for child */ + int status; + + ASSERT_EQ(waitpid(child_pid, &status, 0), child_pid); + EXPECT_EQ(WEXITSTATUS(status), 0); + ASSERT_NE(ret, 0); + } +} + +TEST_HARNESS_MAIN --- base-commit: 40f92e79b0aabbf3575e371f9054657a421a3e79 change-id: 20250618-toicsti-bug-7822b8e94a32 Best regards, -- Abhinav Saxena <xandfury(a)gmail.com>

3 months

3
2
0 0

[RFC PATCH 1/2] kunit: tool: Move qemu architecture dependency checks into a function

by David Gow

Currently the RISC-V qemu architecture config has some code to check for the presence of the BIOS files before loading, printing a message and quitting if it's not present. However, this prevents us from loading the architecture file even just to inspect it if the dependencies are not present. Instead, have kunit.py look for a check_dependencies function, and call it if present only when the architecture config is being used. This is necessary for future changes which enumerate or automatically select an architecture. Signed-off-by: David Gow <davidgow(a)google.com> --- tools/testing/kunit/kunit_kernel.py | 5 +++++ tools/testing/kunit/qemu_configs/riscv.py | 10 ++++++---- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py index 260d8d9aa1db..c3201a76da24 100644 --- a/tools/testing/kunit/kunit_kernel.py +++ b/tools/testing/kunit/kunit_kernel.py @@ -230,6 +230,11 @@ def _get_qemu_ops(config_path: str, assert isinstance(spec.loader, importlib.abc.Loader) spec.loader.exec_module(config) + # Check for any per-architecture dependencies + if hasattr(config, 'check_dependencies'): + if not config.check_dependencies(): + raise ValueError('Missing dependencies for ' + config_path) + if not hasattr(config, 'QEMU_ARCH'): raise ValueError('qemu_config module missing "QEMU_ARCH": ' + config_path) params: qemu_config.QemuArchParams = config.QEMU_ARCH diff --git a/tools/testing/kunit/qemu_configs/riscv.py b/tools/testing/kunit/qemu_configs/riscv.py index c87758030ff7..3c271d1005d9 100644 --- a/tools/testing/kunit/qemu_configs/riscv.py +++ b/tools/testing/kunit/qemu_configs/riscv.py @@ -6,10 +6,12 @@ import sys OPENSBI_FILE = 'opensbi-riscv64-generic-fw_dynamic.bin' OPENSBI_PATH = '/usr/share/qemu/' + OPENSBI_FILE -if not os.path.isfile(OPENSBI_PATH): - print('\n\nOpenSBI bios was not found in "' + OPENSBI_PATH + '".\n' - 'Please ensure that qemu-system-riscv is installed, or edit the path in "qemu_configs/riscv.py"\n') - sys.exit() +def check_dependencies() -> bool: + if not os.path.isfile(OPENSBI_PATH): + print('\n\nOpenSBI bios was not found in "' + OPENSBI_PATH + '".\n' + 'Please ensure that qemu-system-riscv is installed, or edit the path in "qemu_configs/riscv.py"\n') + return False + return True QEMU_ARCH = QemuArchParams(linux_arch='riscv', kconfig=''' -- 2.50.1.552.g942d659e1b-goog

3 months

1
1
0 0

[PATCH v2] Subject: [PATCH] selftests: panic: Add test module to trigger kernel panic

by Vishal Parmar

This patch adds a new test module under tools/testing/selftests/panic that intentionally triggers a kernel panic for test and diagnostic purposes. The goal is to provide a reproducible and isolated kernel panic event for testing crash dump mechanisms or validating kernel panic handling behavior. The test includes: - A kernel module that calls panic() in init. - A Makefile to build the kernel module. - A run.sh script to load the module and capture panic logs. Changes in v2: - Added run.sh - Added reference output log of run.sh Signed-off-by: Vishal Parmar <vishistriker(a)gmail.com> --- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/panic/Makefile | 13 +++++++++ .../selftests/panic/panic_trigger_test.c | 26 +++++++++++++++++ .../selftests/panic/reference_output_log.txt | 29 +++++++++++++++++++ tools/testing/selftests/panic/run.sh | 17 +++++++++++ 5 files changed, 86 insertions(+) create mode 100644 tools/testing/selftests/panic/Makefile create mode 100644 tools/testing/selftests/panic/panic_trigger_test.c create mode 100644 tools/testing/selftests/panic/reference_output_log.txt create mode 100755 tools/testing/selftests/panic/run.sh diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 339b31e6a6b5..7b824470a9b3 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -78,6 +78,7 @@ TARGETS += net/packetdrill TARGETS += net/rds TARGETS += net/tcp_ao TARGETS += nsfs +TARGETS += panic TARGETS += pci_endpoint TARGETS += pcie_bwctrl TARGETS += perf_events diff --git a/tools/testing/selftests/panic/Makefile b/tools/testing/selftests/panic/Makefile new file mode 100644 index 000000000000..e4a1b88a63b2 --- /dev/null +++ b/tools/testing/selftests/panic/Makefile @@ -0,0 +1,13 @@ +# SPDX-License-Identifier: GPL-2.0 + +obj-m := panic_trigger_test.o + +KDIR := $(abspath ../../../../) +PWD := $(shell pwd) + +all: + $(MAKE) -C $(KDIR) M=$(PWD) modules + +clean: + $(MAKE) -C $(KDIR) M=$(PWD) clean + rm -f *.mod.c *.o *.ko *.order *.symvers diff --git a/tools/testing/selftests/panic/panic_trigger_test.c b/tools/testing/selftests/panic/panic_trigger_test.c new file mode 100644 index 000000000000..4e2e043fe3ad --- /dev/null +++ b/tools/testing/selftests/panic/panic_trigger_test.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * panic_test.c - Module to test kernel panic + */ + +#include <linux/module.h> +#include <linux/init.h> + +static int __init panic_test_init(void) +{ + pr_info("Triggering a deliberate kernel panic now.\n"); + panic("Triggered by panic_test module."); + return 0; +} + +static void __exit panic_test_exit(void) +{ + pr_info("This should not be printed, as system panics on init.\n"); +} + +module_init(panic_test_init); +module_exit(panic_test_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Vishal Parmar"); +MODULE_DESCRIPTION("Module to trigger kernel panic for testing"); diff --git a/tools/testing/selftests/panic/reference_output_log.txt b/tools/testing/selftests/panic/reference_output_log.txt new file mode 100644 index 000000000000..2c8143bf6c4a --- /dev/null +++ b/tools/testing/selftests/panic/reference_output_log.txt @@ -0,0 +1,29 @@ +[*] Inserting module: panic_trigger_test.ko +[ 30.377307] panic_trigger_test: loading out-of-tree module taints kernel. +[ 30.380328] Triggering a deliberate kernel panic now. +[ 30.382369] Kernel panic - not syncing: Triggered by panic_test module. +[ 30.383349] CPU: 1 UID: 0 PID: 99 Comm: insmod Tainted: G O 6.16.0-rc7-00140-gec2df4364666 #1 PREEMPT(voluntary) +[ 30.383349] Tainted: [O]=OOT_MODULE +[ 30.383349] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 +[ 30.383349] Call Trace: +[ 30.383349] <TASK> +[ 30.383349] panic+0x325/0x380 +[ 30.383349] ? __pfx_panic_test_init+0x10/0x10 [panic_trigger_test] +[ 30.383349] panic_test_init+0x1c/0xff0 [panic_trigger_test] +[ 30.383349] do_one_initcall+0x55/0x220 +[ 30.383349] do_init_module+0x5b/0x230 +[ 30.383349] __do_sys_init_module+0x150/0x180 +[ 30.383349] do_syscall_64+0xa4/0x260 +[ 30.383349] entry_SYSCALL_64_after_hwframe+0x77/0x7f +[ 30.383349] RIP: 0033:0x7f88f09177d9 +[ 30.383349] Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d f7 05 8 +[ 30.383349] RSP: 002b:00007ffc16317848 EFLAGS: 00000206 ORIG_RAX: 00000000000000af +[ 30.383349] RAX: ffffffffffffffda RBX: 000055a4a84b0eae RCX: 00007f88f09177d9 +[ 30.383349] RDX: 000055a4a84b0eae RSI: 00000000000019e8 RDI: 000055a4c9b4b370 +[ 30.383349] RBP: 00007ffc16317bd0 R08: 000055a4c9b4b310 R09: 00000000000019e8 +[ 30.383349] R10: 0000000000000007 R11: 0000000000000206 R12: 00007ffc16317bd8 +[ 30.383349] R13: 00007ffc16317be0 R14: 000055a4a84b0eae R15: 00007f88f0b25020 +[ 30.383349] </TASK> +[ 30.383349] Kernel Offset: 0x10000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) +[ 30.383349] ---[ end Kernel panic - not syncing: Triggered by panic_test module. ]--- + diff --git a/tools/testing/selftests/panic/run.sh b/tools/testing/selftests/panic/run.sh new file mode 100755 index 000000000000..ffa20dc22708 --- /dev/null +++ b/tools/testing/selftests/panic/run.sh @@ -0,0 +1,17 @@ +# tools/testing/selftests/panic/run.sh + +#!/bin/sh +set -e + +MOD_NAME="panic_trigger_test.ko" +LOG_FILE="panic_log.txt" + +echo "[*] Clearing dmesg..." +dmesg -c + +echo "[*] Inserting module: $MOD_NAME" +insmod ./$MOD_NAME + +echo "[*] Capturing dmesg..." +dmesg > "$LOG_FILE" + -- 2.39.5

3 months, 1 week

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Re: [PATCH v5] char: misc: add test cases

by Geert Uytterhoeven

Hi Thadeu,, On Sun, 15 Jun 2025 at 23:31, Thadeu Lima de Souza Cascardo <cascardo(a)igalia.com> wrote: > > Add test cases for static and dynamic minor number allocation and > deallocation. > > While at it, improve description and test suite name. > > Some of the cases include: > > - that static and dynamic allocation reserved the expected minors. > > - that registering duplicate minors or duplicate names will fail. > > - that failing to create a sysfs file (due to duplicate names) will > deallocate the dynamic minor correctly. > > - that dynamic allocation does not allocate a minor number in the static > range. > > - that there are no collisions when mixing dynamic and static allocations. > > - that opening devices with various minor device numbers work. > > - that registering a static number in the dynamic range won't conflict with > a dynamic allocation. > > This last test verifies the bug fixed by commit 6d04d2b554b1 ("misc: > misc_minor_alloc to use ida for all dynamic/misc dynamic minors") has not > regressed. > > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo(a)igalia.com> Thanks for your patch, which is now commit 74d8361be3441dff ("char: misc: add test cases") in linus/master stable/master > Changes in v5: > - Make miscdevice unit test built-in only > - Make unit test require CONFIG_KUNIT=y Why were these changes made? This means the test is no longer available if KUNIT=m, and I can no longer just load the module when I want to run the test. > - Link to v4: https://lore.kernel.org/r/20250423-misc-dynrange-v4-0-133b5ae4ca18@igalia.c… > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -2506,8 +2506,8 @@ config TEST_IDA > tristate "Perform selftest on IDA functions" > > config TEST_MISC_MINOR > - tristate "miscdevice KUnit test" if !KUNIT_ALL_TESTS > - depends on KUNIT > + bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS > + depends on KUNIT=y > default KUNIT_ALL_TESTS > help > Kunit test for miscdevice API, specially its behavior in respect to Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert(a)linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds

3 months, 1 week

2
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[PATCH 5.10.y 4/4] selftests/memfd: add test for mapping write-sealed memfd read-only

by Isaac J. Manjarres

From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> [ Upstream commit ea0916e01d0b0f2cce1369ac1494239a79827270 ] Now we have reinstated the ability to map F_SEAL_WRITE mappings read-only, assert that we are able to do this in a test to ensure that we do not regress this again. Link: https://lkml.kernel.org/r/a6377ec470b14c0539b4600cf8fa24bf2e4858ae.17328047… Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Jann Horn <jannh(a)google.com> Cc: Julian Orth <ju.orth(a)gmail.com> Cc: Liam R. Howlett <Liam.Howlett(a)Oracle.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Signed-off-by: Isaac J. Manjarres <isaacmanjarres(a)google.com> --- tools/testing/selftests/memfd/memfd_test.c | 43 ++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index fba322d1c67a..5d1ad547416a 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -186,6 +186,24 @@ static void *mfd_assert_mmap_shared(int fd) return p; } +static void *mfd_assert_mmap_read_shared(int fd) +{ + void *p; + + p = mmap(NULL, + mfd_def_size, + PROT_READ, + MAP_SHARED, + fd, + 0); + if (p == MAP_FAILED) { + printf("mmap() failed: %m\n"); + abort(); + } + + return p; +} + static void *mfd_assert_mmap_private(int fd) { void *p; @@ -802,6 +820,30 @@ static void test_seal_future_write(void) close(fd); } +static void test_seal_write_map_read_shared(void) +{ + int fd; + void *p; + + printf("%s SEAL-WRITE-MAP-READ\n", memfd_str); + + fd = mfd_assert_new("kern_memfd_seal_write_map_read", + mfd_def_size, + MFD_CLOEXEC | MFD_ALLOW_SEALING); + + mfd_assert_add_seals(fd, F_SEAL_WRITE); + mfd_assert_has_seals(fd, F_SEAL_WRITE); + + p = mfd_assert_mmap_read_shared(fd); + + mfd_assert_read(fd); + mfd_assert_read_shared(fd); + mfd_fail_write(fd); + + munmap(p, mfd_def_size); + close(fd); +} + /* * Test SEAL_SHRINK * Test whether SEAL_SHRINK actually prevents shrinking @@ -1056,6 +1098,7 @@ int main(int argc, char **argv) test_seal_write(); test_seal_future_write(); + test_seal_write_map_read_shared(); test_seal_shrink(); test_seal_grow(); test_seal_resize(); -- 2.50.1.552.g942d659e1b-goog

3 months, 1 week

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[PATCH 5.15.y 4/4] selftests/memfd: add test for mapping write-sealed memfd read-only

by Isaac J. Manjarres

From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> [ Upstream commit ea0916e01d0b0f2cce1369ac1494239a79827270 ] Now we have reinstated the ability to map F_SEAL_WRITE mappings read-only, assert that we are able to do this in a test to ensure that we do not regress this again. Link: https://lkml.kernel.org/r/a6377ec470b14c0539b4600cf8fa24bf2e4858ae.17328047… Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Jann Horn <jannh(a)google.com> Cc: Julian Orth <ju.orth(a)gmail.com> Cc: Liam R. Howlett <Liam.Howlett(a)Oracle.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Signed-off-by: Isaac J. Manjarres <isaacmanjarres(a)google.com> --- tools/testing/selftests/memfd/memfd_test.c | 43 ++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 94df2692e6e4..15a90db80836 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -186,6 +186,24 @@ static void *mfd_assert_mmap_shared(int fd) return p; } +static void *mfd_assert_mmap_read_shared(int fd) +{ + void *p; + + p = mmap(NULL, + mfd_def_size, + PROT_READ, + MAP_SHARED, + fd, + 0); + if (p == MAP_FAILED) { + printf("mmap() failed: %m\n"); + abort(); + } + + return p; +} + static void *mfd_assert_mmap_private(int fd) { void *p; @@ -802,6 +820,30 @@ static void test_seal_future_write(void) close(fd); } +static void test_seal_write_map_read_shared(void) +{ + int fd; + void *p; + + printf("%s SEAL-WRITE-MAP-READ\n", memfd_str); + + fd = mfd_assert_new("kern_memfd_seal_write_map_read", + mfd_def_size, + MFD_CLOEXEC | MFD_ALLOW_SEALING); + + mfd_assert_add_seals(fd, F_SEAL_WRITE); + mfd_assert_has_seals(fd, F_SEAL_WRITE); + + p = mfd_assert_mmap_read_shared(fd); + + mfd_assert_read(fd); + mfd_assert_read_shared(fd); + mfd_fail_write(fd); + + munmap(p, mfd_def_size); + close(fd); +} + /* * Test SEAL_SHRINK * Test whether SEAL_SHRINK actually prevents shrinking @@ -1056,6 +1098,7 @@ int main(int argc, char **argv) test_seal_write(); test_seal_future_write(); + test_seal_write_map_read_shared(); test_seal_shrink(); test_seal_grow(); test_seal_resize(); -- 2.50.1.552.g942d659e1b-goog

3 months, 1 week

1
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[PATCH 6.1.y 4/4] selftests/memfd: add test for mapping write-sealed memfd read-only

by Isaac J. Manjarres

From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> [ Upstream commit ea0916e01d0b0f2cce1369ac1494239a79827270 ] Now we have reinstated the ability to map F_SEAL_WRITE mappings read-only, assert that we are able to do this in a test to ensure that we do not regress this again. Link: https://lkml.kernel.org/r/a6377ec470b14c0539b4600cf8fa24bf2e4858ae.17328047… Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Jann Horn <jannh(a)google.com> Cc: Julian Orth <ju.orth(a)gmail.com> Cc: Liam R. Howlett <Liam.Howlett(a)Oracle.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Signed-off-by: Isaac J. Manjarres <isaacmanjarres(a)google.com> --- tools/testing/selftests/memfd/memfd_test.c | 43 ++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 94df2692e6e4..15a90db80836 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -186,6 +186,24 @@ static void *mfd_assert_mmap_shared(int fd) return p; } +static void *mfd_assert_mmap_read_shared(int fd) +{ + void *p; + + p = mmap(NULL, + mfd_def_size, + PROT_READ, + MAP_SHARED, + fd, + 0); + if (p == MAP_FAILED) { + printf("mmap() failed: %m\n"); + abort(); + } + + return p; +} + static void *mfd_assert_mmap_private(int fd) { void *p; @@ -802,6 +820,30 @@ static void test_seal_future_write(void) close(fd); } +static void test_seal_write_map_read_shared(void) +{ + int fd; + void *p; + + printf("%s SEAL-WRITE-MAP-READ\n", memfd_str); + + fd = mfd_assert_new("kern_memfd_seal_write_map_read", + mfd_def_size, + MFD_CLOEXEC | MFD_ALLOW_SEALING); + + mfd_assert_add_seals(fd, F_SEAL_WRITE); + mfd_assert_has_seals(fd, F_SEAL_WRITE); + + p = mfd_assert_mmap_read_shared(fd); + + mfd_assert_read(fd); + mfd_assert_read_shared(fd); + mfd_fail_write(fd); + + munmap(p, mfd_def_size); + close(fd); +} + /* * Test SEAL_SHRINK * Test whether SEAL_SHRINK actually prevents shrinking @@ -1056,6 +1098,7 @@ int main(int argc, char **argv) test_seal_write(); test_seal_future_write(); + test_seal_write_map_read_shared(); test_seal_shrink(); test_seal_grow(); test_seal_resize(); -- 2.50.1.552.g942d659e1b-goog

3 months, 1 week

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[PATCH 6.6.y 4/4] selftests/memfd: add test for mapping write-sealed memfd read-only

by Isaac J. Manjarres

From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> [ Upstream commit ea0916e01d0b0f2cce1369ac1494239a79827270 ] Now we have reinstated the ability to map F_SEAL_WRITE mappings read-only, assert that we are able to do this in a test to ensure that we do not regress this again. Link: https://lkml.kernel.org/r/a6377ec470b14c0539b4600cf8fa24bf2e4858ae.17328047… Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Jann Horn <jannh(a)google.com> Cc: Julian Orth <ju.orth(a)gmail.com> Cc: Liam R. Howlett <Liam.Howlett(a)Oracle.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Signed-off-by: Isaac J. Manjarres <isaacmanjarres(a)google.com> --- tools/testing/selftests/memfd/memfd_test.c | 43 ++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index e92b60eecb7d..9c9c82fd18a7 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -285,6 +285,24 @@ static void *mfd_assert_mmap_shared(int fd) return p; } +static void *mfd_assert_mmap_read_shared(int fd) +{ + void *p; + + p = mmap(NULL, + mfd_def_size, + PROT_READ, + MAP_SHARED, + fd, + 0); + if (p == MAP_FAILED) { + printf("mmap() failed: %m\n"); + abort(); + } + + return p; +} + static void *mfd_assert_mmap_private(int fd) { void *p; @@ -986,6 +1004,30 @@ static void test_seal_future_write(void) close(fd); } +static void test_seal_write_map_read_shared(void) +{ + int fd; + void *p; + + printf("%s SEAL-WRITE-MAP-READ\n", memfd_str); + + fd = mfd_assert_new("kern_memfd_seal_write_map_read", + mfd_def_size, + MFD_CLOEXEC | MFD_ALLOW_SEALING); + + mfd_assert_add_seals(fd, F_SEAL_WRITE); + mfd_assert_has_seals(fd, F_SEAL_WRITE); + + p = mfd_assert_mmap_read_shared(fd); + + mfd_assert_read(fd); + mfd_assert_read_shared(fd); + mfd_fail_write(fd); + + munmap(p, mfd_def_size); + close(fd); +} + /* * Test SEAL_SHRINK * Test whether SEAL_SHRINK actually prevents shrinking @@ -1603,6 +1645,7 @@ int main(int argc, char **argv) test_seal_write(); test_seal_future_write(); + test_seal_write_map_read_shared(); test_seal_shrink(); test_seal_grow(); test_seal_resize(); -- 2.50.1.552.g942d659e1b-goog

3 months, 1 week

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[PATCH v2 0/2] seccomp: Fix a race with WAIT_KILLABLE_RECV if the tracer replies too fast

by Johannes Nixdorf

If WAIT_KILLABLE_RECV was specified, and an event is received, the tracee's syscall is not supposed to be interruptible. This was not properly ensured if the reply was sent too fast, and an interrupting signal was received before the reply was processed on the tracee side. This series fixes the bug and adds a test case for it to the selftests. Signed-off-by: Johannes Nixdorf <johannes(a)nixdorf.dev> --- Changes in v2: - Added a selftest for the bug. - Link to v1: https://lore.kernel.org/r/20250723-seccomp-races-v1-1-bef5667ce30a@nixdorf.… --- Johannes Nixdorf (2): seccomp: Fix a race with WAIT_KILLABLE_RECV if the tracer replies too fast selftests/seccomp: Add a test for the WAIT_KILLABLE_RECV fast reply race kernel/seccomp.c | 13 ++- tools/testing/selftests/seccomp/seccomp_bpf.c | 130 ++++++++++++++++++++++++++ 2 files changed, 136 insertions(+), 7 deletions(-) --- base-commit: 89be9a83ccf1f88522317ce02f854f30d6115c41 change-id: 20250721-seccomp-races-e97897d6d94b Best regards, -- Johannes Nixdorf <johannes(a)nixdorf.dev>

3 months, 1 week

3
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[GIT PULL] kselftest next update for Linux 6.17-rc1

by Shuah Khan

Hi Linus, Please pull this kselftest next update for Linux 6.17-rc1. Fixes - false failure of subsystem event test - glob filter test to use mutex_unlock() instead of mutex_trylock() - several spelling errors in tests - test_kexec_jump build errors - pidfd test duplicate-symbol warnings for SCHED_ CPP symbols Adds a reliable check for suspend to breakpoints suspend test Improvements to ipc test diff is attached. thanks, -- Shuah ---------------------------------------------------------------- The following changes since commit 19272b37aa4f83ca52bdf9c16d5d81bdd1354494: Linux 6.16-rc1 (2025-06-08 13:44:43 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux_kselftest-next-6.17-rc1 for you to fetch changes up to 30fb5e134f05800dc424f8aa1d69841a6bdd9a54: selftests/pidfd: Fix duplicate-symbol warnings for SCHED_ CPP symbols (2025-07-24 16:14:45 -0600) ---------------------------------------------------------------- linux_kselftest-next-6.17-rc1 Fixes - false failure of subsystem event test - glob filter test to use mutex_unlock() instead of mutex_trylock() - several spelling errors in tests - test_kexec_jump build errors - pidfd test duplicate-symbol warnings for SCHED_ CPP symbols Adds a reliable check for suspend to breakpoints suspend test Improvements to ipc test ---------------------------------------------------------------- Ankit Chauhan (1): selftests/ptrace: Fix spelling mistake "multible" -> "multiple" Jihed Chaibi (1): selftests/cpu-hotplug: fix typo in hotplaggable_offline_cpus function name Masami Hiramatsu (Google) (1): selftests: tracing: Use mutex_unlock for testing glob filter Moon Hee Lee (2): selftests: breakpoints: use suspend_stats to reliably check suspend success selftests/kexec: fix test_kexec_jump build Nick Huang (1): selftests: ipc: Replace fail print statements with ksft_test_result_fail Paul E. McKenney (1): selftests/pidfd: Fix duplicate-symbol warnings for SCHED_ CPP symbols Shuah Khan (1): selftests: print installation complete message Steven Rostedt (1): selftests/tracing: Fix false failure of subsystem event test Tianyi Cui (1): selftests: Add version file to kselftest installation dir tools/testing/selftests/Makefile | 8 ++++ .../breakpoints/step_after_suspend_test.c | 41 ++++++++++++++----- .../selftests/cpu-hotplug/cpu-on-off-test.sh | 4 +- .../ftrace/test.d/event/subsystem-enable.tc | 28 ++++++++++++- .../ftrace/test.d/ftrace/func-filter-glob.tc | 2 +- tools/testing/selftests/ipc/msgque.c | 47 +++++++++++----------- tools/testing/selftests/kexec/Makefile | 2 +- tools/testing/selftests/pidfd/pidfd.h | 9 +++++ tools/testing/selftests/ptrace/peeksiginfo.c | 2 +- 9 files changed, 102 insertions(+), 41 deletions(-) ----------------------------------------------------------------

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