xtensa: fix lock_mm_and_find_vma in case VMA not found

jcmvbkbc · torvalds · commit 03f889378f33 · 2023-07-01T08:00:05.000-07:00
MMU version of lock_mm_and_find_vma releases the mm lock before returning when VMA is not found. Do the same in noMMU version. This fixes hang on an attempt to handle protection fault. Fixes: d85a143 ("xtensa: fix NOMMU build with lock_mm_and_find_vma() conversion") Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/nommu.c b/mm/nommu.c
@@ -637,8 +637,13 @@ EXPORT_SYMBOL(find_vma);
 struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm,
 			unsigned long addr, struct pt_regs *regs)
 {
+	struct vm_area_struct *vma;
+
 	mmap_read_lock(mm);
-	return vma_lookup(mm, addr);
+	vma = vma_lookup(mm, addr);
+	if (!vma)
+		mmap_read_unlock(mm);
+	return vma;
 }
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -637,8 +637,13 @@ EXPORT_SYMBOL(find_vma);`
`637`	`637`	`struct vm_area_struct lock_mm_and_find_vma(struct mm_struct mm,`
`638`	`638`	`unsigned long addr, struct pt_regs *regs)`
`639`	`639`	`{`
	`640`	`+ struct vm_area_struct *vma;`
	`641`	`+`
`640`	`642`	`mmap_read_lock(mm);`
`641`		`- return vma_lookup(mm, addr);`
	`643`	`+ vma = vma_lookup(mm, addr);`
	`644`	`+ if (!vma)`
	`645`	`+ mmap_read_unlock(mm);`
	`646`	`+ return vma;`
`642`	`647`	`}`
`643`	`648`
`644`	`649`	`/*`