In the Linux kernel, the following vulnerability has been resolved: binder: fix alloc->vma_vm_mm null-ptr dereference Syzbot reported a couple issues introduced by commit 44e602b4e52f ("binder_alloc: add missing mmap_lock calls when using the VMA"), in which we attempt to acquire the mmap_lock when alloc->vma_vm_mm has not been initialized yet. This can happen if a binder_proc receives a transaction without having previously called mmap() to setup the binder_proc->alloc space in [1]. Also, a similar issue occurs via binder_alloc_print_pages() when we try to dump the debugfs binder stats file in [2]. Sample of syzbot's crash report: ================================================================== KASAN: null-ptr-deref in range [0x0000000000000128-0x000000000000012f] CPU: 0 PID: