Messages in this thread Patch in this message | | | Date | Fri, 06 Nov 2009 14:14:49 -0800 | From | Greg KH <> | Subject | [51/99] NOMMU: Dont pass NULL pointers to fput() in do_mmap_pgoff() |
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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);
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