mm: allow fault_dirty_shared_page() to be called under the VMA lock

By making maybe_unlock_mmap_for_io() handle the VMA lock correctly, we make fault_dirty_shared_page() safe to be called without the mmap lock held. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Reported-by: David Hildenbrand <[email protected]> Tested-by: Suren Baghdasaryan <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
sirdarckcat · Aug 21, 2023 · 0790e1e · 0790e1e
1 parent 7e2fca5
commit 0790e1e
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/mm/internal.h b/mm/internal.h
@@ -706,7 +706,7 @@ static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf,
 	if (fault_flag_allow_retry_first(flags) &&
 	    !(flags & FAULT_FLAG_RETRY_NOWAIT)) {
 		fpin = get_file(vmf->vma->vm_file);
-		mmap_read_unlock(vmf->vma->vm_mm);
+		release_fault_lock(vmf);
 	}
 	return fpin;
 }