@@ -2,7 +2,10 @@
#include <linux/limits.h>
#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/wait.h>
#include <unistd.h>
+#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <signal.h>
@@ -12,6 +15,115 @@
#include "../kselftest.h"
#include "cgroup_util.h"
+static int touch_anon(char *buf, size_t size)
+{
+ int fd;
+ char *pos = buf;
+
+ fd = open("/dev/urandom", O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ while (size > 0) {
+ ssize_t ret = read(fd, pos, size);
+
+ if (ret < 0) {
+ if (errno != EINTR) {
+ close(fd);
+ return -1;
+ }
+ } else {
+ pos += ret;
+ size -= ret;
+ }
+ }
+ close(fd);
+
+ return 0;
+}
+
+static int alloc_and_touch_anon_noexit(const char *cgroup, void *arg)
+{
+ int ppid = getppid();
+ size_t size = (size_t)arg;
+ void *buf;
+
+ buf = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
+ 0, 0);
+ if (buf == MAP_FAILED)
+ return -1;
+
+ if (touch_anon((char *)buf, size)) {
+ munmap(buf, size);
+ return -1;
+ }
+
+ while (getppid() == ppid)
+ sleep(1);
+
+ munmap(buf, size);
+ return 0;
+}
+
+/*
+ * Create a child process that allocates and touches 100MB, then waits to be
+ * killed. Wait until the child is attached to the cgroup, kill all processes
+ * in that cgroup and wait until "cgroup.procs" is empty. At this point try to
+ * destroy the empty cgroup. The test helps detect race conditions between
+ * dying processes leaving the cgroup and cgroup destruction path.
+ */
+static int test_cgcore_destroy(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *cg_test = NULL;
+ int child_pid;
+ char buf[PAGE_SIZE];
+
+ cg_test = cg_name(root, "cg_test");
+
+ if (!cg_test)
+ goto cleanup;
+
+ for (int i = 0; i < 10; i++) {
+ if (cg_create(cg_test))
+ goto cleanup;
+
+ child_pid = cg_run_nowait(cg_test, alloc_and_touch_anon_noexit,
+ (void *) MB(100));
+
+ if (child_pid < 0)
+ goto cleanup;
+
+ /* wait for the child to enter cgroup */
+ if (cg_wait_for_proc_count(cg_test, 1))
+ goto cleanup;
+
+ if (cg_killall(cg_test))
+ goto cleanup;
+
+ /* wait for cgroup to be empty */
+ while (1) {
+ if (cg_read(cg_test, "cgroup.procs", buf, sizeof(buf)))
+ goto cleanup;
+ if (buf[0] == '\0')
+ break;
+ usleep(1000);
+ }
+
+ if (rmdir(cg_test))
+ goto cleanup;
+
+ if (waitpid(child_pid, NULL, 0) < 0)
+ goto cleanup;
+ }
+ ret = KSFT_PASS;
+cleanup:
+ if (cg_test)
+ cg_destroy(cg_test);
+ free(cg_test);
+ return ret;
+}
+
/*
* A(0) - B(0) - C(1)
* \ D(0)
@@ -512,6 +624,7 @@ struct corecg_test {
T(test_cgcore_populated),
T(test_cgcore_proc_migration),
T(test_cgcore_thread_migration),
+ T(test_cgcore_destroy),
};
#undef T