Attachment 298407 Details for Bug 435291 – latest linked-list reproducer

latest linked-list reproducer

mutex_lt3-7.c (text/plain), 5.37 KB, created by Jeff Layton on 2008-03-18 15:41:00 UTC

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Creator: Jeff Layton

Created: 2008-03-18 15:41:00 UTC

Size: 5.37 KB

patch

obsolete

>#include <stdio.h>
>#include <stdlib.h>
>#include <unistd.h>
>#include <fcntl.h>
>#include <sys/types.h>
>#include <sys/stat.h>
>#include <sys/mman.h>
>#include <sys/wait.h>
>#include <semaphore.h>
>#include <string.h>
>#include <errno.h>
>#include <time.h>
>
>#define SEMKEY "mutex_lt3"
>#define NRTHREADS 10
>#define MP (NRTHREADS + 1)
>
>struct x {
>	int val;
>	int next;
>/*	int garbage[1000]; */
>	int garbage[1022];
>};
>
>struct fs {
>	struct x pids[MP];
>};
>
>void print_error(char *s) {
>	fprintf(stderr, "<%d> %s (%d:%s)\n", getpid(), s, errno, strerror(errno));
>}
>
>void print_message(char *s) {
>	fprintf(stderr, "<%d> %s\n", getpid(), s);
>}
>
>void dump_list(pid_t pid, struct fs *fs) {
>	int i;
>
>	for (i=0; i<MP; i++) {
>		printf("(%u) %d: val=%d next=%d\n", pid, i, fs->pids[i].val,
>			fs->pids[i].next);
>	}
>}
>
>int main(int argc, char **argv) {
>
>	int fd;
>	caddr_t addr;
>	struct fs *fsp;
>	struct fs b;
>	struct x *pp;
>	int flags = O_RDWR;
>	pid_t p1;
>	int i, j, iter = 0, loc;
>	int iterations = 400;
>	int count = 0;
>	int status;
>	int pstatus = 0;
>	sem_t *sem;
>	pid_t pid;
>
>	srand((int)time(0));
>
>	memset(&b, 0, sizeof(b));
>
>	if (argc > 2) {
>		fprintf(stderr, "usage: %s <file>\n", argv[0]);
>		exit(1);
>	}
>
>	unlink(argv[1]);
>	fd = open(argv[1], flags | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
>	if (fd == -1) {
>		print_error("can't create specified file");
>		exit(1);
>	}
>
>	sem_unlink(SEMKEY);
>	sem = sem_open(SEMKEY, O_RDWR|O_CREAT|O_EXCL, 0600, 1);
>	if (sem == SEM_FAILED) {
>		print_error("sem_open failed");
>		goto error_exit;
>	}
>
>	write(fd, &b, sizeof(struct fs));
>
>	addr = mmap(0, sizeof(struct fs), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
>	if (addr == MAP_FAILED) {
>		print_error("mmap failed");
>		goto error_exit;
>	}
>
>	fsp = (struct fs *)addr;
>	pp = fsp->pids;
>
>	for (i=0; i<MP; i++) {
>		pp[i].val = -1;
>		pp[i].next = -1;
>	}
>
>	if (msync((void *)addr, sizeof(struct fs), MS_SYNC) < 0) {
>		print_error("msync");
>	}
>	if (munmap((char *)addr, sizeof(struct fs)) != 0) {
>		print_error("munmap");
>		return 1;
>	}
>	if (close(fd) != 0) {
>		print_error("close");
>	}
>	sem_close(sem);
>
>	/* spawn children */
>	printf("%u: ", getpid());
>	fflush(stdout);
>	for (i=0; i < NRTHREADS; i++) {
>		pid = fork();
>		if (pid < 0) {
>			print_error("fork");
>			return 1;
>		} else if (pid == 0) {
>			goto child_task;
>		} else {
>			printf(" %u", pid);
>			fflush(stdout);
>		}
>	}
>	printf("\n");
>
>	while (i > 0) {
>		waitpid(-1, &status, 0);
>		if (WEXITSTATUS(status) != 0)
>			pstatus = WEXITSTATUS(status);
>		i--;
>	}
>
>	return pstatus;
>
>child_task:
>	status = 0;
>	fd = open(argv[1], flags, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
>	if (fd == -1) {
>		print_error("can't open specified file");
>		return 1;
>	}
>
>	sem = sem_open(SEMKEY, 0);
>	if (sem == SEM_FAILED) {
>		print_error("sem_open failed");
>		goto error_exit;
>	}
>
>	addr = mmap(0, sizeof(struct fs), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
>	if (addr == MAP_FAILED) {
>		print_error("mmap failed");
>		goto error_exit;
>	}
>
>#if 0
>	status = madvise(addr, sizeof(struct fs), MADV_RANDOM);
>	if (status != 0) {
>		print_error("madvise failed");
>		goto error_exit;
>	}
>#endif
>
>	fsp = (struct fs *)addr;
>	pp = fsp->pids;
>
>	p1 = getpid();
>	while (--iterations != 0) {
>		/* login: find first empty slot, insert into linked list */
>		if ((status = sem_wait(sem))) {
>			print_error("lock");
>			goto clean_exit;
>		}
>		for (i=1;i<MP;i++) {
>			if (pp[i].val == -1) {
>				j = i;
>				break;
>			}
>		}
>		if (i==MP) {
>			print_message("ran out of space");
>			status = -ENOSPC;
>			goto unlock_exit;
>		}
>		pp[j].next = pp[0].next; pp[0].next = j; pp[j].val = p1;
>		if ((status = sem_post(sem))) {
>			print_error("unlock");
>			goto clean_exit;
>		}
>
>		/* do something to hold the mutex for a small time */
>//		for (loc = 0; loc < 1000000; loc++) i *= 3;
>//		for (loc = 0; loc < 500000; loc++) i *= 3;
>//		usleep(1);
>
>		/* logout: find my number and remove it */
>		if ((status = sem_wait(sem))) {
>			print_error("lock");
>			goto clean_exit;
>		}
>		i = 0; loc=0; iter = 0;
>		while (pp[i].next != -1) {
>			if (pp[pp[i].next].val == p1) {
>				pp[pp[i].next].val = -1;
>				j = pp[i].next;
>				pp[i].next = pp[pp[i].next].next;
>				pp[j].next = -1;
>				loc=1;
>				break;
>			}
>			/* shouldn't need to traverse list but once */
>			if (iter > MP) {
>				fprintf(stderr, "<%d> looped 1\n", p1);
>				dump_list(p1, fsp);
>				status = 1;
>				goto unlock_exit;
>			}
>			i = pp[i].next;
>			iter++;
>		}
>		if (!loc) {
>			fprintf(stderr, "<%d> can't find me to logout - expected at slot %d\n", p1, j);
>			dump_list(p1, fsp);
>			status = 1;
>			goto unlock_exit;
>		}
>		if ((status = sem_post(sem))) {
>			print_error("unlock");
>			goto clean_exit;
>		}
>
>		/* integrity check */
>		if ((status = sem_wait(sem))) {
>			print_error("lock");
>			goto clean_exit;
>		}
>		i = 0; iter=0;
>		while (pp[i].next != -1) {
>			iter++;
>			i = pp[i].next;
>			if (iter>MP) {
>				fprintf(stderr, "<%d> looped 2\n", p1);
>				dump_list(p1, fsp);
>				status = 1;
>				goto unlock_exit;
>			}
>		}
>
>		if ((status = sem_post(sem))) {
>			print_error("unlock");
>			goto clean_exit;
>		}
>		count += 1;
>	}
>
>	goto clean_exit;
>
>unlock_exit:
>	if (sem_post(sem)) {
>		print_error("unlock");
>	}
>
>clean_exit:
>	if (msync((void *)addr, sizeof(struct fs), MS_SYNC) < 0) {
>		print_error("msync");
>	}
>	if (munmap((char *)addr, sizeof(struct fs)) != 0) {
>		print_error("munmap");
>	}
>error_exit:
>	if (close(fd) != 0) {
>		print_error("close");
>	}
>
>	sem_close(sem);
>	//fprintf(stderr, "<%d> done, count =%d\n", p1, count);
>	return status;
>}

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Attachments on bug 435291: 296231 | 296232 | 297648 | 297649 | 298407 | 306161 | 309133