commit 0e64123141f3854e695eb4924d82b52856691466
author Olivier Deprez <olivier.deprez@arm.com> Thu Sep 23 10:07:05 2021 +0200
committer Olivier Deprez <olivier.deprez@arm.com> Tue Oct 26 16:50:53 2021 +0100
tree 9f79e140db584f9b107f4e33373a0075983df1f4
parent 98854e9675dc7d951fa9c4e10d9c9d230c54bde6

Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>

mm/madvise.c

diff --git a/mm/madvise.c b/mm/madvise.c
index 94c343b..1107e99 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -288,9 +288,9 @@
 	 */
 	*prev = NULL;	/* tell sys_madvise we drop mmap_sem */
 	get_file(file);
-	up_read(&current->mm->mmap_sem);
 	offset = (loff_t)(start - vma->vm_start)
 			+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+	up_read(&current->mm->mmap_sem);
 	vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED);
 	fput(file);
 	down_read(&current->mm->mmap_sem);
@@ -335,12 +335,14 @@
 		}
 
 		page = pmd_page(orig_pmd);
+
+		/* Do not interfere with other mappings of this page */
+		if (page_mapcount(page) != 1)
+			goto huge_unlock;
+
 		if (next - addr != HPAGE_PMD_SIZE) {
 			int err;
 
-			if (page_mapcount(page) != 1)
-				goto huge_unlock;
-
 			get_page(page);
 			spin_unlock(ptl);
 			lock_page(page);
@@ -378,9 +380,9 @@
 		return 0;
 	}
 
+regular_page:
 	if (pmd_trans_unstable(pmd))
 		return 0;
-regular_page:
 #endif
 	tlb_change_page_size(tlb, PAGE_SIZE);
 	orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
@@ -426,6 +428,10 @@
 			continue;
 		}
 
+		/* Do not interfere with other mappings of this page */
+		if (page_mapcount(page) != 1)
+			continue;
+
 		VM_BUG_ON_PAGE(PageTransCompound(page), page);
 
 		if (pte_young(ptent)) {