From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Thu, 7 May 2020 20:07:49 +0000 (-0400)
Subject: mm/mmap: Fix maple tree calculation for topdown with alignment mask.
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0ca43e9e68dd5c593c1ec041f35fd91868408852;p=users%2Fjedix%2Flinux-maple.git

mm/mmap: Fix maple tree calculation for topdown with alignment mask.

When using alignment mask, calculate the address correctly.

Found by LTP futex_wake04

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

diff --git a/mm/mmap.c b/mm/mmap.c
index c37e74bbb95c1..942b9b12a29a4 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2278,11 +2278,10 @@ static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
 	if (mas_get_unmapped_area_rev(&mas, info->low_limit, info->high_limit,
 				length))
 		return -ENOMEM;
+
 	rcu_read_unlock();
-	gap = mas.index;
-	// Not sure why this is needed..
-	if (mas.max > info->high_limit)
-	gap = ((gap) & ~info->align_mask) + info->align_offset;
+	gap = (mas.index + info->align_mask - info->align_offset) &
+		(~info->align_mask);
 	/*
 	 * Adjust search limits by the desired length.
 	 * See implementation comment at top of unmapped_area().
@@ -2377,8 +2376,8 @@ found_highest:
 				info->low_limit, length);
 		pr_err("mas.min %lu max %lu mas.last %lu\n", mas.min, mas.max,
 				mas.last);
-		pr_err("mas.index %lu align %lu offset %lu\n", mas.index,
-				info->align_offset, info->align_mask);
+		pr_err("mas.index %lu align mask %lu offset %lu\n", mas.index,
+				info->align_mask, info->align_offset);
 		pr_err("rb_find_vma find on %lu => %px (%px)\n", mas.index,
 				rb_find_vma(mm, mas.index), vma);
 		mt_dump(&mm->mm_mt);