The following commit has been merged in the linux branch: commit 89a8640279f8bb78aaf778d1fc5c4a6778f18064 Author: David Howells dhowells@redhat.com Date: Fri Oct 30 13:13:26 2009 +0000

NOMMU: Don't pass NULL pointers to fput() in do_mmap_pgoff()

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 Cc: stable@kernel.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org

diff --git a/mm/nommu.c b/mm/nommu.c index 5189b5a..9876fa0 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1362,9 +1362,11 @@ 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);