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);
--
Cheers,
Stephen Rothwell
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