Re: Process hangs system on exit

Once again new details of this strange behaviour.

Here is complete and very simple "killing" application.
And here (http://discussions.apple.com/thread....36846&tstart=0) this "bug" was confirmed on the similar system.

Firstly you should run this one (and DO NOT perform exit from it):

=========================================================
#include <stdio.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <string.h>
#include <sys/types.h>
#include <fcntl.h>

#define SHM_NAME "/tmp/zeroSharedMemory" /* Shared memory name */
#define SHM_SIZE 0x10000 /* Shared memory region size in bytes (64Kb) */

/* Clean ups given shared memory object */
static inline void destroy_shared_memory(int shm_fd, const char* shm_name)
{
    if(-1 == close(shm_fd))
    {
        perror("close");
        exit(-1);
    }
    if (-1 == shm_unlink(shm_name))
    {
        perror("shm_unlink");
        exit(-1);
    }
}

/* Creates shared memory object, zeroing it and waiting any key to be inputted */
int main (int argc, const char * argv[]) {
    int shm_fd; //shared memory file descriptor
    void* shm_addr; //shared memory attach address

    /* Create new shared memory object on filesystem */
    shm_fd = shm_open(SHM_NAME, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
    if(shm_fd == -1)
    {
        perror("shm_open");
        return -1;
    }

    /* Truncate to the defined size */
    if (ftruncate(shm_fd, (off_t) SHM_SIZE) == -1)
    {
        perror("ftruncate");
        destroy_shared_memory(shm_fd, SHM_NAME);
        return -1;
    }

    /* mmap shared memory object into virtual address space */
    shm_addr = mmap(NULL,
        (size_t)(SHM_SIZE),
        PROT_READ | PROT_WRITE,
        MAP_SHARED,
        shm_fd,
        (off_t)0);

    if(shm_addr == MAP_FAILED)
    {
        perror("mmap");
        destroy_shared_memory(shm_fd, SHM_NAME);
        return -1;
    }

    /* Zeroing memory */
    memset(shm_addr, 0, (size_t)SHM_SIZE);

    /* Waiting until key pressed ... and perform cleanup */
    printf("Press any key to perform cleanup and exit ...\n");
    getchar();
    destroy_shared_memory(shm_fd, SHM_NAME);
    return 0;
}
=========================================================

Now start this one:

=========================================================
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <string.h>
#include <sys/types.h>
#include <fcntl.h>

#define SHM_NAME "/tmp/zeroSharedMemory" /* Shared memory name */
#define SHM_SIZE 0x10000 /* Shared memory region size in bytes (64Kb) */
#define REGIONS_NUM 16000 /* mmap regions number */

/* Close shared memory object descriptor */
static inline void close_shared_memory(int shm_fd, const char* shm_name)
{
    if(-1 == close(shm_fd))
    {
        perror("close");
        exit(-1);
    }
}

/* Opens shared memory object, mmaps it REGIONS_NUM times, checks each header and exits */
int main (int argc, const char * argv[]) {
    int shm_fd; //shared memory file descriptor
    void* shm_addr[REGIONS_NUM]; //shared memory attach address(es)
    int i; //for iteration

    /* Open shared memory object on filesystem */
    shm_fd = shm_open(SHM_NAME, O_RDWR, 0);
    if(shm_fd == -1)
    {
        perror("shm_open");
        return -1;
    }

    /* mmap zero page of the shared memory object into virtual address space */
    printf("Going to create initial mapping ...");
    for(i = 0; i < REGIONS_NUM; i++)
    {
        shm_addr = mmap(NULL,
            (size_t)SHM_SIZE,
            PROT_READ | PROT_WRITE,
            MAP_SHARED,
            shm_fd,
            (off_t) 0);

        if(MAP_FAILED == shm_addr)
        {
            perror("mmap");
            close_shared_memory(shm_fd, SHM_NAME);
            return -1;
        }
    }
    printf(" OK\n");

    printf("Going to unmap ...");
    /* unmap a number of blocks */
    for(i = 0; i < REGIONS_NUM; i++)
    {
        // Check header of the block
        if( ((char*)(shm_addr))[0] != '\0')
        {
            // Actually we don't perform this operation in this example application since header
            // always contains zeroes ...
            munmap(shm_addr, (size_t)SHM_SIZE);
        }
    }
    printf(" OK\n");

    /* Waiting until key pressed ... and perform cleanup */
    printf("Press any key to perform clean up and exit ...\n");
    getchar();
    close_shared_memory(shm_fd, SHM_NAME);
    return 0;
}
=========================================================

My system (PPC, 10.4.11) hangs (only mouse pointer is alive) on exit from the second process for 3-4 seconds.
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