From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Tue, 16 Mar 2021 20:00:14 +0000 (-0400)
Subject: mlock rcu fix
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=48aa7fd12cde5ec87cd319b7878c0efb98760f9e;p=users%2Fjedix%2Flinux-maple.git

mlock rcu fix

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---

diff --git a/mm/mlock.c b/mm/mlock.c
index 8194507c9710..fe2ea9688d3d 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -623,6 +623,7 @@ static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
 	if (mm == NULL)
 		mm = current->mm;
 
+	rcu_read_lock();
 	mas_for_each(&mas, vma, start + len) {
 		if (start >= vma->vm_end)
 			continue;
@@ -638,6 +639,7 @@ static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
 			count += vma->vm_end - vma->vm_start;
 		}
 	}
+	rcu_read_unlock();
 
 	return count >> PAGE_SHIFT;
 }
@@ -757,6 +759,7 @@ static int apply_mlockall_flags(int flags)
 			to_add |= VM_LOCKONFAULT;
 	}
 
+	rcu_read_lock();
 	mas_for_each(&mas, vma, ULONG_MAX) {
 		vm_flags_t newflags;
 
@@ -765,9 +768,12 @@ static int apply_mlockall_flags(int flags)
 
 		/* Ignore errors */
 		mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
+		rcu_read_unlock();
 		mas_pause(&mas);
 		cond_resched();
+		rcu_read_lock();
 	}
+	rcu_read_unlock();
 out:
 	return 0;
 }