Re: [PATCH 1/7] binder: fix alloc->vma_vm_mm null-ptr dereference

[Carlos Llamas]

On Mon, Aug 29, 2022 at 01:34:52PM -0700, Andrew Morton wrote:
> On Mon, 29 Aug 2022 20:12:48 +0000 Carlos Llamas <cmllamas@xxxxxxxxxx> wrote:
> 
> > 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].
> 
> Thanks.  I assume you'll be merging all these into mainline?

Yes, I believe Greg will pick up these patches into his char-misc tree.

> 
> > 
> > Fixes: 44e602b4e52f ("binder_alloc: add missing mmap_lock calls when using the VMA")
> > Reported-by: syzbot+f7dc54e5be28950ac459@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Reported-by: syzbot+a75ebe0452711c9e56d9@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Cc: <stable@xxxxxxxxxxxxxxx> # v5.15+
> 
> 44e602b4e52f is only present in 6.0-rcX?

Right, it was just added to the stable queue earlier today:
https://lore.kernel.org/all/20220829105814.857786586@xxxxxxxxxxxxxxxxxxx/
https://lore.kernel.org/all/20220829105809.855177179@xxxxxxxxxxxxxxxxxxx/