1 files changed, 11 insertions, 1 deletions
diff --git a/Kernel/FileSystem/BlockBasedFileSystem.cpp b/Kernel/FileSystem/BlockBasedFileSystem.cpp
index 2b329a7b9b..cf2916d3d1 100644
--- a/Kernel/FileSystem/BlockBasedFileSystem.cpp
+++ b/Kernel/FileSystem/BlockBasedFileSystem.cpp
@@ -133,6 +133,16 @@ ErrorOr<void> BlockBasedFileSystem::write_block(BlockIndex index, const UserOrKe
     VERIFY(offset + count <= block_size());
     dbgln_if(BBFS_DEBUG, "BlockBasedFileSystem::write_block {}, size={}", index, count);
 
+    // NOTE: We copy the `data` to write into a local buffer before taking the cache lock.
+    //       This makes sure any page faults caused by accessing the data will occur before
+    //       we tie down the cache.
+    auto buffered_data_or_error = ByteBuffer::create_uninitialized(count);
+    if (!buffered_data_or_error.has_value())
+        return ENOMEM;
+    auto buffered_data = buffered_data_or_error.release_value();
+
+    TRY(data.read(buffered_data.bytes()));
+
     return m_cache.with_exclusive([&](auto& cache) -> ErrorOr<void> {
         if (!allow_cache) {
             flush_specific_block_if_needed(index);
@@ -147,7 +157,7 @@ ErrorOr<void> BlockBasedFileSystem::write_block(BlockIndex index, const UserOrKe
             // Fill the cache first.
             TRY(read_block(index, nullptr, block_size()));
         }
-        TRY(data.read(entry.data + offset, count));
+        memcpy(entry.data + offset, buffered_data.data(), count);
 
         cache->mark_dirty(entry);
         entry.has_data = true;