From: David Howells Date: Fri, 30 Oct 2009 13:13:26 +0000 (+0000) Subject: NOMMU: Don't pass NULL pointers to fput() in do_mmap_pgoff() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=89a8640279f8bb78aaf778d1fc5c4a6778f18064;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git 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 Signed-off-by: David Howells Acked-by: Robin Getz Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- diff --git a/mm/nommu.c b/mm/nommu.c index 5189b5aed8c0..9876fa0c3ad3 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);