Move the padding of 0-sized buffers to an earlier stage to account for
this round up during the alloc->free_async_space check.

Fixes: 74310e06be4d ("android: binder: Move buffer out of area shared with user space")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
---
 drivers/android/binder_alloc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index adcec5ec0959..abff1bafcc43 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -407,6 +407,10 @@ static struct binder_buffer *binder_alloc_new_buf_locked(
 				alloc->pid, extra_buffers_size);
 		return ERR_PTR(-EINVAL);
 	}
+
+	/* Pad 0-size buffers so they get assigned unique addresses */
+	size = max(size, sizeof(void *));
+
 	if (is_async &&
 	    alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
@@ -415,9 +419,6 @@ static struct binder_buffer *binder_alloc_new_buf_locked(
 		return ERR_PTR(-ENOSPC);
 	}
 
-	/* Pad 0-size buffers so they get assigned unique addresses */
-	size = max(size, sizeof(void *));
-
 	while (n) {
 		buffer = rb_entry(n, struct binder_buffer, rb_node);
 		BUG_ON(!buffer->free);
-- 
2.43.0.rc2.451.g8631bc7472-goog

On Fri, Dec 01, 2023 at 05:21:33PM +0000, Carlos Llamas wrote:
> Move the padding of 0-sized buffers to an earlier stage to account for
> this round up during the alloc->free_async_space check.
> 
> Fixes: 74310e06be4d ("android: binder: Move buffer out of area shared with user space")
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> Signed-off-by: Carlos Llamas <cmllamas@google.com>
> ---

Sorry, I forgot to Cc: stable@vger.kernel.org.

--
Carlos Llamas

On Thu, Jan 18, 2024 at 07:32:08PM +0000, Carlos Llamas wrote:
> On Fri, Dec 01, 2023 at 05:21:33PM +0000, Carlos Llamas wrote:
> > Move the padding of 0-sized buffers to an earlier stage to account for
> > this round up during the alloc->free_async_space check.
> > 
> > Fixes: 74310e06be4d ("android: binder: Move buffer out of area shared with user space")
> > Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> > Signed-off-by: Carlos Llamas <cmllamas@google.com>
> > ---
> 
> Sorry, I forgot to Cc: stable@vger.kernel.org.


<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

On Fri, Jan 19, 2024 at 06:48:53AM +0100, Greg Kroah-Hartman wrote:
> On Thu, Jan 18, 2024 at 07:32:08PM +0000, Carlos Llamas wrote:
> > On Fri, Dec 01, 2023 at 05:21:33PM +0000, Carlos Llamas wrote:
> > > Move the padding of 0-sized buffers to an earlier stage to account for
> > > this round up during the alloc->free_async_space check.
> > > 
> > > Fixes: 74310e06be4d ("android: binder: Move buffer out of area shared with user space")
> > > Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> > > Signed-off-by: Carlos Llamas <cmllamas@google.com>
> > > ---
> > 
> > Sorry, I forgot to Cc: stable@vger.kernel.org.
> 
> 
> <formletter>
> 
> This is not the correct way to submit patches for inclusion in the
> stable kernel tree.  Please read:
>     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> for how to do this properly.
> 
> </formletter>

Oops, here is the complete info:

Commit ID: 3091c21d3e9322428691ce0b7a0cfa9c0b239eeb
Subject:   "binder: fix async space check for 0-sized buffers"
Reason:    Fixes an incorrect calculation of available space.
Versions:  v4.19+

Thanks,
--
Carlos Llamas

On Fri, Jan 19, 2024 at 05:11:26PM +0000, Carlos Llamas wrote:
> On Fri, Jan 19, 2024 at 06:48:53AM +0100, Greg Kroah-Hartman wrote:
> > On Thu, Jan 18, 2024 at 07:32:08PM +0000, Carlos Llamas wrote:
> > > On Fri, Dec 01, 2023 at 05:21:33PM +0000, Carlos Llamas wrote:
> > > > Move the padding of 0-sized buffers to an earlier stage to account for
> > > > this round up during the alloc->free_async_space check.
> > > > 
> > > > Fixes: 74310e06be4d ("android: binder: Move buffer out of area shared with user space")
> > > > Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> > > > Signed-off-by: Carlos Llamas <cmllamas@google.com>
> > > > ---
> > > 
> > > Sorry, I forgot to Cc: stable@vger.kernel.org.
> > 
> > 
> > <formletter>
> > 
> > This is not the correct way to submit patches for inclusion in the
> > stable kernel tree.  Please read:
> >     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > for how to do this properly.
> > 
> > </formletter>
> 
> Oops, here is the complete info:
> 
> Commit ID: 3091c21d3e9322428691ce0b7a0cfa9c0b239eeb
> Subject:   "binder: fix async space check for 0-sized buffers"
> Reason:    Fixes an incorrect calculation of available space.
> Versions:  v4.19+

Now queued up, thanks.

greg k-h