diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 3007b28206d7..6f7155b8d198 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3138,7 +3138,6 @@ static void binder_transaction(struct binder_proc *proc, t->buffer = NULL; goto err_binder_alloc_buf_failed; } - t->buffer->allow_user_free = 0; t->buffer->debug_id = t->debug_id; t->buffer->transaction = t; t->buffer->target_node = target_node; @@ -3634,14 +3633,18 @@ static int binder_thread_write(struct binder_proc *proc, buffer = binder_alloc_prepare_to_free(&proc->alloc, data_ptr); - if (buffer == NULL) { - binder_user_error("%d:%d BC_FREE_BUFFER u%016llx no match\n", - proc->pid, thread->pid, (u64)data_ptr); - break; - } - if (!buffer->allow_user_free) { - binder_user_error("%d:%d BC_FREE_BUFFER u%016llx matched unreturned buffer\n", - proc->pid, thread->pid, (u64)data_ptr); + if (IS_ERR_OR_NULL(buffer)) { + if (PTR_ERR(buffer) == -EPERM) { + binder_user_error( + "%d:%d BC_FREE_BUFFER u%016llx matched unreturned or currently freeing buffer\n", + proc->pid, thread->pid, + (u64)data_ptr); + } else { + binder_user_error( + "%d:%d BC_FREE_BUFFER u%016llx no match\n", + proc->pid, thread->pid, + (u64)data_ptr); + } break; } binder_debug(BINDER_DEBUG_FREE_BUFFER, diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 1d9db2ef26bd..baecb4bf9d9b 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -149,14 +149,12 @@ static struct binder_buffer *binder_alloc_prepare_to_free_locked( else { /* * Guard against user threads attempting to - * free the buffer twice + * free the buffer when in use by kernel or + * after it's already been freed. */ - if (buffer->free_in_progress) { - pr_err("%d:%d FREE_BUFFER u%016llx user freed buffer twice\n", - alloc->pid, current->pid, (u64)user_ptr); - return NULL; - } - buffer->free_in_progress = 1; + if (!buffer->allow_user_free) + return ERR_PTR(-EPERM); + buffer->allow_user_free = 0; return buffer; } } @@ -463,7 +461,7 @@ static struct binder_buffer *binder_alloc_new_buf_locked( rb_erase(best_fit, &alloc->free_buffers); buffer->free = 0; - buffer->free_in_progress = 0; + buffer->allow_user_free = 0; binder_insert_allocated_buffer_locked(alloc, buffer); binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, "%d: binder_alloc_buf size %zd got %pK\n", diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h index 9ef64e563856..fb3238c74c8a 100644 --- a/drivers/android/binder_alloc.h +++ b/drivers/android/binder_alloc.h @@ -50,8 +50,7 @@ struct binder_buffer { unsigned free:1; unsigned allow_user_free:1; unsigned async_transaction:1; - unsigned free_in_progress:1; - unsigned debug_id:28; + unsigned debug_id:29; struct binder_transaction *transaction;