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[51/99] NOMMU: Dont pass NULL pointers to fput() in do_mmap_pgoff()
    2.6.31-stable review patch.  If anyone has any objections, please let us know.

    ------------------
    From: David Howells <dhowells@redhat.com>

    commit 89a8640279f8bb78aaf778d1fc5c4a6778f18064 upstream.

    Don't pass NULL pointers to fput() in the error handling paths of the NOMMU
    do_mmap_pgoff() as it can't handle it.

    The following can be used as a test program:

    int main() { static long long a[1024 * 1024 * 20] = { 0 }; return a;}

    Without the patch, the code oopses in atomic_long_dec_and_test() as called by
    fput() after the kernel complains that it can't allocate that big a chunk of
    memory. With the patch, the kernel just complains about the allocation size
    and then the program segfaults during execve() as execve() can't complete the
    allocation of all the new ELF program segments.

    Reported-by: Robin Getz <rgetz@blackfin.uclinux.org>
    Signed-off-by: David Howells <dhowells@redhat.com>
    Acked-by: Robin Getz <rgetz@blackfin.uclinux.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    mm/nommu.c | 6 ++++--
    1 file changed, 4 insertions(+), 2 deletions(-)

    --- a/mm/nommu.c
    +++ b/mm/nommu.c
    @@ -1384,9 +1384,11 @@ share:
    error_just_free:
    up_write(&nommu_region_sem);
    error:
    - fput(region->vm_file);
    + if (region->vm_file)
    + fput(region->vm_file);
    kmem_cache_free(vm_region_jar, region);
    - fput(vma->vm_file);
    + if (vma->vm_file)
    + fput(vma->vm_file);
    if (vma->vm_flags & VM_EXECUTABLE)
    removed_exe_file_vma(vma->vm_mm);
    kmem_cache_free(vm_area_cachep, vma);



    \
     
     \ /
      Last update: 2009-11-06 23:37    [W:0.032 / U:30.096 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site