Commit 89a86402 authored by David Howells's avatar David Howells Committed by Linus Torvalds

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: default avatarRobin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarRobin Getz <rgetz@blackfin.uclinux.org>
Cc: stable@kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2e2ec952
...@@ -1362,9 +1362,11 @@ unsigned long do_mmap_pgoff(struct file *file, ...@@ -1362,9 +1362,11 @@ unsigned long do_mmap_pgoff(struct file *file,
error_just_free: error_just_free:
up_write(&nommu_region_sem); up_write(&nommu_region_sem);
error: error:
fput(region->vm_file); if (region->vm_file)
fput(region->vm_file);
kmem_cache_free(vm_region_jar, region); 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) if (vma->vm_flags & VM_EXECUTABLE)
removed_exe_file_vma(vma->vm_mm); removed_exe_file_vma(vma->vm_mm);
kmem_cache_free(vm_area_cachep, vma); kmem_cache_free(vm_area_cachep, vma);
......
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