| 1 |
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| 2 |
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| 3 | #ifndef _FUTEX_THREAD_H
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| 4 | #define _FUTEX_THREAD_H
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| 5 | #include <errno.h>
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| 6 | #include <pthread.h>
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| 7 | #include <stdio.h>
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| 8 | #include <string.h>
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| 9 | #include <unistd.h>
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| 10 |
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| 11 | #include "kselftest_harness.h"
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| 12 |
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| 13 | #define USEC_PER_SEC 1000000L
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| 14 | #define WAIT_FOR_THREAD_SECS 1
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| 15 | #define WAIT_FOR_THREAD_USECS (WAIT_FOR_THREAD_SECS * USEC_PER_SEC)
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| 16 | #define WAIT_THREAD_RETRIES 100
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| 17 |
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| 18 | struct futex_thread {
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| 19 | pthread_t thread;
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| 20 | pthread_barrier_t barrier;
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| 21 | pid_t tid;
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| 22 | int (*threadfn)(void *arg);
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| 23 | void *arg;
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| 24 | int retval;
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| 25 | };
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| 26 |
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| 27 | static inline int __wait_for_thread(FILE *fp, struct __test_metadata *_metadata)
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| 28 | {
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| 29 | unsigned int sleep_time_us = WAIT_FOR_THREAD_USECS / WAIT_THREAD_RETRIES;
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| 30 | char buf[80] = "";
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| 31 |
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| 32 | for (int i = 0; i < WAIT_THREAD_RETRIES; i++) {
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| 33 | if (!fgets(buf, sizeof(buf), fp))
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| 34 | return EIO;
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| 35 | if (!strncmp(buf, "futex", 5))
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| 36 | return 0;
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| 37 | usleep(sleep_time_us);
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| 38 | rewind(fp);
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| 39 | }
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| 40 |
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| 41 | TH_LOG("/proc/$PID/wchan contains \"%s\". Trying to continue.", buf);
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| 42 | return 0;
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| 43 | }
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| 44 |
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| 45 | static void *__futex_thread_fn(void *arg)
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| 46 | {
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| 47 | struct futex_thread *t = arg;
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| 48 |
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| 49 | t->tid = gettid();
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| 50 | pthread_barrier_wait(&t->barrier);
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| 51 | t->retval = t->threadfn(t->arg);
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| 52 | return NULL;
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| 53 | }
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| 54 |
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| 55 | |
| 56 | * futex_wait_for_thread - Wait for the child thread to sleep in the futex context
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| 57 | * @t: Thread handle.
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| 58 | * @_metadata: Test metadata for TH_LOG() context
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| 59 |
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| 60 | static inline int futex_wait_for_thread(struct futex_thread *t, struct __test_metadata *_metadata)
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| 61 | {
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| 62 | char fname[80];
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| 63 | FILE *fp;
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| 64 | int res;
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| 65 |
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| 66 | snprintf(fname, sizeof(fname), "/proc/%d/wchan", t->tid);
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| 67 | fp = fopen(fname, "r");
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| 68 | if (!fp) {
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| 69 |
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| 70 | if (errno != ENOENT)
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| 71 | return errno;
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| 72 | TH_LOG("/proc/$PID/wchan not accessible, continue with sleep()");
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| 73 | sleep(WAIT_FOR_THREAD_SECS);
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| 74 | return 0;
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| 75 | }
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| 76 |
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| 77 | res = __wait_for_thread(fp, _metadata);
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| 78 | fclose(fp);
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| 79 | return res;
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| 80 | }
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| 81 |
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| 82 | |
| 83 | * futex_thread_create - Create a new thread for testing.
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| 84 | * @t: The handle of the newly created thread.
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| 85 | * @threadfn: The new thread starts execution by invoking threadfn
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| 86 | * @arg: The parameters passed to threadfn.
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| 87 |
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| 88 | static inline int futex_thread_create(struct futex_thread *t, int (*threadfn)(void *), void *arg)
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| 89 | {
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| 90 | pthread_barrier_init(&t->barrier, NULL, 2);
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| 91 |
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| 92 | t->tid = 0;
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| 93 | t->threadfn = threadfn;
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| 94 | t->arg = arg;
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| 95 |
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| 96 | if (pthread_create(&t->thread, NULL, __futex_thread_fn, t) < 0) {
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| 97 | int ret = errno;
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| 98 | pthread_barrier_destroy(&t->barrier);
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| 99 | return ret;
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| 100 | }
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| 101 |
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| 102 | pthread_barrier_wait(&t->barrier);
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| 103 | return 0;
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| 104 | }
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| 105 |
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| 106 | |
| 107 | * futex_thread_destroy - Wait for and reclaim the resources of the thread.
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| 108 | * @t: Thread handle.
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| 109 |
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| 110 | static inline int futex_thread_destroy(struct futex_thread *t)
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| 111 | {
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| 112 | pthread_join(t->thread, NULL);
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| 113 | pthread_barrier_destroy(&t->barrier);
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| 114 | return t->retval;
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| 115 | }
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| 116 |
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| 117 | #endif
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