lkml.org 
[lkml]   [2010]   [Apr]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: mprotect() failed: Cannot allocate memory
    From
    Date
    Le mercredi 21 avril 2010 à 01:44 +0200, Paweł Sikora a écrit :
    > On Wednesday 21 April 2010 01:17:22 Mike Frysinger wrote:
    > > On Tuesday 20 April 2010 19:05:20 Paweł Sikora wrote:
    > > > i'm trying to debug an ugly application with ElectricFence.
    > >
    > > electricfence does a lot of ugly memory tricks to do its thing, including,
    > > but not limited to, overriding memory related symbols. best to seek help
    > > from the electricfence authors.
    >
    > so, let's avoid EF and run following test:
    >
    > #include <stdio.h>
    > #include <stdlib.h>
    > #include <unistd.h>
    > #include <sys/mman.h>
    >
    > void* my_alloc( size_t n )
    > {
    > size_t ps = getpagesize();
    > printf( "request for %Zd bytes => ", n );
    > /* alloc PAGE_SIZE + n */
    > char* p = mmap( 0, ps + n, PROT_READ | PROT_WRITE, MAP_SHARED |
    > MAP_ANONYMOUS, -1, 0 );
    > if ( p == MAP_FAILED )
    > __builtin_abort();
    > /* block guard page */
    > int rc = mprotect( p, ps, PROT_NONE );
    > if ( rc != 0 )
    > __builtin_abort();
    > char* q = p + ps;
    > printf( "guard page @ %p, allocated region @ %p\n", p, q );
    > return q;
    > }
    >
    > int main()
    > {
    > #define N 100
    > size_t NN = 4*100*100;
    > size_t kmax = 100;
    > int i;
    >
    > double **bm = (double **)my_alloc( NN * sizeof( double* ) );
    > for( i = 0; i < NN; ++i )
    > {
    > bm[ i ] = (double*)my_alloc( kmax * sizeof( double ) );
    > }
    > // leak...
    > return 0;
    > }
    >
    > and the result is...
    >
    > (...)
    > mmap(NULL, 4896, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, 0) =
    > 0x7f5fd97df000
    > mprotect(0x7f5fd97df000, 4096, PROT_NONE) = -1 ENOMEM (Cannot allocate memory)

    Have you checked available memory on your system ? Or user limit ?

    You test program is going to allocate
    79 + 1 pages for bm
    1 + 1 for each double arrays (x 40000)

    So in the end your program is allocating 80080 pages, so about
    312MBytes.

    It not that big for a 64bits system.

    Check limits such as
    -d the maximum size of a process's data segment
    -l the maximum size a process may lock into memory
    -m the maximum resident set size

    Regards.

    --
    Yann Droneaud


    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2010-04-21 10:25    [W:0.024 / U:30.208 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site