lkml.org 
[lkml]   [2009]   [Nov]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[28/99] mbind(): fix leak of never putback pages
    2.6.31-stable review patch.  If anyone has any objections, please let us know.

    ------------------
    From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

    commit ab8a3e14e6f8e567560f664bbd29aefb306a274e upstream.

    If mbind() receives an invalid address, do_mbind leaks a page. The
    following test program detects this leak.

    This patch fixes it.

    migrate_efault.c
    =======================================
    #include <numaif.h>
    #include <numa.h>
    #include <sys/mman.h>
    #include <stdio.h>
    #include <unistd.h>
    #include <stdlib.h>
    #include <string.h>

    static unsigned long pagesize;

    static void* make_hole_mapping(void)
    {

    void* addr;

    addr = mmap(NULL, pagesize*3, PROT_READ|PROT_WRITE,
    MAP_ANON|MAP_PRIVATE, 0, 0);
    if (addr == MAP_FAILED)
    return NULL;

    /* make page populate */
    memset(addr, 0, pagesize*3);

    /* make memory hole */
    munmap(addr+pagesize, pagesize);

    return addr;
    }

    int main(int argc, char** argv)
    {
    void* addr;
    int ch;
    int node;
    struct bitmask *nmask = numa_allocate_nodemask();
    int err;
    int node_set = 0;

    while ((ch = getopt(argc, argv, "n:")) != -1){
    switch (ch){
    case 'n':
    node = strtol(optarg, NULL, 0);
    numa_bitmask_setbit(nmask, node);
    node_set = 1;
    break;
    default:
    ;
    }
    }
    argc -= optind;
    argv += optind;

    if (!node_set)
    numa_bitmask_setbit(nmask, 0);

    pagesize = getpagesize();

    addr = make_hole_mapping();

    err = mbind(addr, pagesize*3, MPOL_BIND, nmask->maskp, nmask->size, MPOL_MF_MOVE_ALL);
    if (err)
    perror("mbind ");

    return 0;
    }
    =======================================

    Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Acked-by: Christoph Lameter <cl@linux-foundation.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    mm/mempolicy.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    --- a/mm/mempolicy.c
    +++ b/mm/mempolicy.c
    @@ -1058,7 +1058,8 @@ static long do_mbind(unsigned long start

    if (!err && nr_failed && (flags & MPOL_MF_STRICT))
    err = -EIO;
    - }
    + } else
    + putback_lru_pages(&pagelist);

    up_write(&mm->mmap_sem);
    mpol_put(new);



    \
     
     \ /
      Last update: 2009-11-06 23:45    [W:4.129 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site