diff options
| -rw-r--r-- | tools/testing/selftests/proc/.gitignore | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/proc/Makefile | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/proc/proc-2-is-kthread.c | 53 | ||||
| -rw-r--r-- | tools/testing/selftests/proc/proc-self-isnt-kthread.c | 37 |
4 files changed, 94 insertions, 0 deletions
diff --git a/tools/testing/selftests/proc/.gitignore b/tools/testing/selftests/proc/.gitignore index a156ac5dd2c6..973968f45bba 100644 --- a/tools/testing/selftests/proc/.gitignore +++ b/tools/testing/selftests/proc/.gitignore @@ -2,6 +2,7 @@ /fd-001-lookup /fd-002-posix-eq /fd-003-kthread +/proc-2-is-kthread /proc-fsconfig-hidepid /proc-loadavg-001 /proc-multiple-procfs @@ -9,6 +10,7 @@ /proc-pid-vm /proc-self-map-files-001 /proc-self-map-files-002 +/proc-self-isnt-kthread /proc-self-syscall /proc-self-wchan /proc-subset-pid diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile index cd95369254c0..6066f607f758 100644 --- a/tools/testing/selftests/proc/Makefile +++ b/tools/testing/selftests/proc/Makefile @@ -7,11 +7,13 @@ TEST_GEN_PROGS := TEST_GEN_PROGS += fd-001-lookup TEST_GEN_PROGS += fd-002-posix-eq TEST_GEN_PROGS += fd-003-kthread +TEST_GEN_PROGS += proc-2-is-kthread TEST_GEN_PROGS += proc-loadavg-001 TEST_GEN_PROGS += proc-empty-vm TEST_GEN_PROGS += proc-pid-vm TEST_GEN_PROGS += proc-self-map-files-001 TEST_GEN_PROGS += proc-self-map-files-002 +TEST_GEN_PROGS += proc-self-isnt-kthread TEST_GEN_PROGS += proc-self-syscall TEST_GEN_PROGS += proc-self-wchan TEST_GEN_PROGS += proc-subset-pid diff --git a/tools/testing/selftests/proc/proc-2-is-kthread.c b/tools/testing/selftests/proc/proc-2-is-kthread.c new file mode 100644 index 000000000000..f13668fb482e --- /dev/null +++ b/tools/testing/selftests/proc/proc-2-is-kthread.c @@ -0,0 +1,53 @@ +/* + * Copyright (c) 2024 Alexey Dobriyan <adobriyan@gmail.com> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +/* Test that kernel thread is reported as such. */ +#undef NDEBUG +#include <assert.h> +#include <errno.h> +#include <fcntl.h> +#include <string.h> +#include <unistd.h> + +int main(void) +{ + /* + * The following solutions don't really work: + * + * 1) jit kernel module which creates kernel thread: + * test becomes arch-specific, + * problems with mandatory module signing, + * problems with lockdown mode, + * doesn't work with CONFIG_MODULES=n at all, + * kthread creation API is formally unstable internal kernel API, + * need a mechanism to report test kernel thread's PID back, + * + * 2) ksoftirqd/0 and kswapd0 look like stable enough kernel threads, + * but their PIDs are unstable. + * + * Check against kthreadd which always seem to exist under pid 2. + */ + int fd = open("/proc/2/status", O_RDONLY); + assert(fd >= 0); + + char buf[4096]; + ssize_t rv = read(fd, buf, sizeof(buf)); + assert(0 <= rv && rv < sizeof(buf)); + buf[rv] = '\0'; + + assert(strstr(buf, "Kthread:\t1\n")); + + return 0; +} diff --git a/tools/testing/selftests/proc/proc-self-isnt-kthread.c b/tools/testing/selftests/proc/proc-self-isnt-kthread.c new file mode 100644 index 000000000000..e01f4e0a91b4 --- /dev/null +++ b/tools/testing/selftests/proc/proc-self-isnt-kthread.c @@ -0,0 +1,37 @@ +/* + * Copyright (c) 2024 Alexey Dobriyan <adobriyan@gmail.com> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +/* Test that userspace program is not kernel thread. */ +#undef NDEBUG +#include <assert.h> +#include <fcntl.h> +#include <string.h> +#include <unistd.h> + +int main(void) +{ + int fd = open("/proc/self/status", O_RDONLY); + assert(fd >= 0); + + char buf[4096]; + ssize_t rv = read(fd, buf, sizeof(buf)); + assert(0 <= rv && rv < sizeof(buf)); + buf[rv] = '\0'; + + /* This test is very much not kernel thread. */ + assert(strstr(buf, "Kthread:\t0\n")); + + return 0; +} |