On Fri, Aug 19, 2022 at 06:40:27PM +1000, Stephen Rothwell wrote:
> Hi Greg,
>
> On Fri, 19 Aug 2022 08:36:21 +0200 Greg KH <greg@xxxxxxxxx> wrote:
> >
> > On Fri, Aug 19, 2022 at 08:28:18AM +1000, Stephen Rothwell wrote:
> > >
> > > Today's linux-next merge of the char-misc.current tree got a conflict in:
> > >
> > > drivers/android/binder_alloc.c
> > >
> > > between commit:
> > >
> > > b3bb668f3dc6 ("binder_alloc: add missing mmap_lock calls when using the VMA")
> > >
> > > from the mm-hotfixes tree and commit:
> > >
> > > d6f35446d076 ("binder_alloc: Add missing mmap_lock calls when using the VMA")
> > >
> > > from the char-misc.current tree.
> > >
> > > I fixed it up (I used the latter as it was committed later even though
> > > the author times were the same) and can carry the fix as necessary. This
> > > is now fixed as far as linux-next is concerned, but any non trivial
> > > conflicts should be mentioned to your upstream maintainer when your tree
> > > is submitted for merging. You may also want to consider cooperating
> > > with the maintainer of the conflicting tree to minimise any particularly
> > > complex conflicts.
> >
> > These should be identical, if not, something went wrong :(
>
> Something went wrong :-)
>
> $ git range-diff b3bb668f3dc6^..b3bb668f3dc6 d6f35446d076^..d6f35446d076
> 1: b3bb668f3dc6 ! 1: d6f35446d076 binder_alloc: add missing mmap_lock calls when using the VMA
> @@ Metadata
> Author: Liam Howlett <liam.howlett@xxxxxxxxxx>
>
> ## Commit message ##
> - binder_alloc: add missing mmap_lock calls when using the VMA
> + binder_alloc: Add missing mmap_lock calls when using the VMA
>
> - Take the mmap_read_lock() when using the VMA in binder_alloc_print_pages()
> - and when checking for a VMA in binder_alloc_new_buf_locked().
> + Take the mmap_read_lock() when using the VMA in
> + binder_alloc_print_pages() and when checking for a VMA in
> + binder_alloc_new_buf_locked().
>
> It is worth noting binder_alloc_new_buf_locked() drops the VMA read lock
> - after it verifies a VMA exists, but may be taken again deeper in the call
> - stack, if necessary.
> + after it verifies a VMA exists, but may be taken again deeper in the
> + call stack, if necessary.
>
> - Link: https://lkml.kernel.org/r/20220810160209.1630707-1-Liam.Howlett@xxxxxxxxxx
> - Fixes: a43cfc87caaf ("android: binder: stop saving a pointer to the VMA")
> - Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> + Fixes: a43cfc87caaf (android: binder: stop saving a pointer to the VMA)
> + Cc: stable <stable@xxxxxxxxxx>
> Reported-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
> - Reported-by: <syzbot+a7b60a176ec13cafb793@xxxxxxxxxxxxxxxxxxxxxxxxx>
> - Acked-by: Carlos Llamas <cmllamas@xxxxxxxxxx>
> + Reported-by: syzbot+a7b60a176ec13cafb793@xxxxxxxxxxxxxxxxxxxxxxxxx
> Tested-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
> - Cc: Minchan Kim <minchan@xxxxxxxxxx>
> - Cc: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx>
> - Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> - Cc: Hridya Valsaraju <hridya@xxxxxxxxxx>
> - Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
> - Cc: Martijn Coenen <maco@xxxxxxxxxxx>
> - Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> - Cc: Todd Kjos <tkjos@xxxxxxxxxxx>
> - Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> - Cc: "Arve Hjønnevåg" <arve@xxxxxxxxxxx>
> - Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> + Acked-by: Carlos Llamas <cmllamas@xxxxxxxxxx>
> + Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> + Link: https://lore.kernel.org/r/20220810160209.1630707-1-Liam.Howlett@xxxxxxxxxx
> + Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>
> ## drivers/android/binder_alloc.c ##
> @@ drivers/android/binder_alloc.c: static struct binder_buffer *binder_alloc_new_buf_locked(
> @@ drivers/android/binder_alloc.c: void binder_alloc_print_pages(struct seq_file *m
> - }
> +
> + mmap_read_lock(alloc->vma_vm_mm);
> -+ if (binder_alloc_get_vma(alloc) == NULL)
> ++ if (binder_alloc_get_vma(alloc) == NULL) {
> ++ mmap_read_unlock(alloc->vma_vm_mm);
> + goto uninitialized;
> + }
> +
> ++ mmap_read_unlock(alloc->vma_vm_mm);
> + for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
> + page = &alloc->pages[i];
> + if (!page->page_ptr)
> @@ drivers/android/binder_alloc.c: void binder_alloc_print_pages(struct seq_file *m
> + active++;
> + else
> + lru++;
> - }
> ++ }
> +
> +uninitialized:
> -+ mmap_read_unlock(alloc->vma_vm_mm);
> mutex_unlock(&alloc->mutex);
> seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
> seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);
>
Oh wow, ok, I'll go drop my version and assume that Andrew's is the more
correct one and let it come through his tree.
thanks,
greg k-h
