diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index 18733d2bdf..c5b62fd26a 100644
--- a/kernel/include/kernel/Process.h
+++ b/kernel/include/kernel/Process.h
@@ -96,7 +96,7 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_getpgid(pid_t);
 
 		BAN::ErrorOr<void> create_file_or_dir(BAN::StringView name, mode_t mode);
-		BAN::ErrorOr<long> open_file(BAN::StringView path, int, mode_t = 0);
+		BAN::ErrorOr<long> open_file(BAN::StringView path, int oflag, mode_t = 0);
 		BAN::ErrorOr<long> sys_open(const char* path, int, mode_t);
 		BAN::ErrorOr<long> sys_openat(int, const char* path, int, mode_t);
 		BAN::ErrorOr<long> sys_close(int fd);
@@ -180,6 +180,8 @@ namespace Kernel
 		// Return false if access was page violation (segfault)
 		BAN::ErrorOr<bool> allocate_page_for_demand_paging(vaddr_t addr);
 
+		BAN::ErrorOr<BAN::String> absolute_path_of(BAN::StringView) const;
+
 	private:
 		Process(const Credentials&, pid_t pid, pid_t parent, pid_t sid, pid_t pgrp);
 		static Process* create_process(const Credentials&, pid_t parent, pid_t sid = 0, pid_t pgrp = 0);
@@ -189,8 +191,6 @@ namespace Kernel
 
 		BAN::ErrorOr<int> block_until_exit(pid_t pid);
 
-		BAN::ErrorOr<BAN::String> absolute_path_of(BAN::StringView) const;
-
 		BAN::ErrorOr<void> validate_string_access(const char*);
 		BAN::ErrorOr<void> validate_pointer_access(const void*, size_t);
 
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index f792008f3b..d544557f50 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -710,6 +710,8 @@ namespace Kernel
 
 	BAN::ErrorOr<long> Process::open_file(BAN::StringView path, int flags, mode_t mode)
 	{
+		LockGuard _(m_lock);
+
 		BAN::String absolute_path = TRY(absolute_path_of(path));
 
 		if (flags & O_CREAT)
@@ -717,6 +719,8 @@ namespace Kernel
 			if (flags & O_DIRECTORY)
 				return BAN::Error::from_errno(ENOTSUP);
 			auto file_or_error = VirtualFileSystem::get().file_from_absolute_path(m_credentials, absolute_path, O_WRONLY);
+			if (!file_or_error.is_error() && (flags & O_EXCL))
+				return BAN::Error::from_errno(EEXIST);
 			if (file_or_error.is_error())
 			{
 				if (file_or_error.error().get_error_code() == ENOENT)
@@ -1744,7 +1748,7 @@ namespace Kernel
 
 	BAN::ErrorOr<BAN::String> Process::absolute_path_of(BAN::StringView path) const
 	{
-		ASSERT(m_lock.is_locked());
+		LockGuard _(m_lock);
 
 		if (path.empty() || path == "."sv)
 			return m_working_directory;