From 3b0995cb4997c948833558888e5e8b750c910a58 Mon Sep 17 00:00:00 2001
From: Johannes Schlatow <johannes.schlatow@genode-labs.com>
Date: Tue, 24 May 2022 13:56:11 +0200
Subject: [PATCH] platform_drv: fix uncaught exception

Calling alloc_dma_buffer() with size=0 will cause an exception in the
ram allocator.

genodelabs/genode#4518
---
 repos/os/src/drivers/platform/session_component.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/repos/os/src/drivers/platform/session_component.cc b/repos/os/src/drivers/platform/session_component.cc
index 5931f7293e..cefc1ad5da 100644
--- a/repos/os/src/drivers/platform/session_component.cc
+++ b/repos/os/src/drivers/platform/session_component.cc
@@ -177,7 +177,11 @@ void Session_component::release_device(Capability<Platform::Device_interface> de
 Genode::Ram_dataspace_capability
 Session_component::alloc_dma_buffer(size_t const size, Cache cache)
 {
-	Ram_dataspace_capability ram_cap = _env_ram.alloc(size, cache);
+	Ram_dataspace_capability ram_cap { };
+
+	try {
+		ram_cap = _env_ram.alloc(size, cache);
+	} catch (Ram_allocator::Denied) { }
 
 	if (!ram_cap.valid()) return ram_cap;