From 2243e226302e1c5cce5d084db5a258c01a761402 Mon Sep 17 00:00:00 2001
From: Eladash <elad3356p@gmail.com>
Date: Mon, 27 Sep 2021 19:25:20 +0300
Subject: [PATCH] sys_fs: Fix race in file stream API

---
 rpcs3/Emu/Cell/lv2/sys_fs.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/rpcs3/Emu/Cell/lv2/sys_fs.cpp b/rpcs3/Emu/Cell/lv2/sys_fs.cpp
index b2f8d187f0..acc04fd45a 100644
--- a/rpcs3/Emu/Cell/lv2/sys_fs.cpp
+++ b/rpcs3/Emu/Cell/lv2/sys_fs.cpp
@@ -3125,6 +3125,7 @@ error_code sys_fs_lsn_lock(ppu_thread&, u32 fd)
 		return CELL_OK;
 	}
 
+	std::lock_guard lock(file->mp->mutex);
 	file->lock.compare_and_swap(0, 1);
 	return CELL_OK;
 }
@@ -3140,7 +3141,14 @@ error_code sys_fs_lsn_unlock(ppu_thread&, u32 fd)
 		return CELL_EBADF;
 	}
 
+	// See sys_fs_lsn_lock
+	if (file->mp == &g_mp_sys_dev_hdd0 || file->mp->flags & lv2_mp_flag::strict_get_block_size)
+	{
+		return CELL_OK;
+	}
+
 	// Unlock unconditionally
+	std::lock_guard lock(file->mp->mutex);
 	file->lock.compare_and_swap(1, 0);
 	return CELL_OK;
 }