binder: fix async space check for 0-sized buffers

commit 3091c21d3e upstream.

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: 74310e06be ("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>
Link: https://lore.kernel.org/r/20231201172212.1813387-5-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Carlos Llamas 2023-12-01 17:21:33 +00:00 committed by Greg Kroah-Hartman
parent 06173edfc7
commit fda6e06e01

View File

@ -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);