linux-kernel - [PATCH] mm/mmap: Drop VM_BUG

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Date:   Tue, 19 Jul 2022 17:09:00 +0000
From:   Liam Howlett <liam.howlett@...cle.com>
To:     "maple-tree@...ts.infradead.org" <maple-tree@...ts.infradead.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Yu Zhao <yuzhao@...gle.com>, Hugh Dickins <hughd@...gle.com>
Subject: [PATCH] mm/mmap: Drop VM_BUG_ON() until better tested

The limits that the maple tree return are trimmed so there is enough space.

Fixes: Fixes: 06fade172129 (mm/mmap: use maple tree for unmapped_area{_topdown})
Reported-by: Yu Zhao <yuzhao@...gle.com>
Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 mm/mmap.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 8c09d1a44081..b0edf7b70872 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1627,8 +1627,6 @@ static unsigned long unmapped_area(struct vm_unmapped_area_info *info)
 
 	gap = mas.index;
 	gap += (info->align_offset - gap) & info->align_mask;
-	VM_BUG_ON(gap + info->length > info->high_limit);
-	VM_BUG_ON(gap + info->length > mas.last);
 	return gap;
 }
 
@@ -1658,8 +1656,6 @@ static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
 
 	gap = mas.last + 1 - info->length;
 	gap -= (gap - info->align_offset) & info->align_mask;
-	VM_BUG_ON(gap < info->low_limit);
-	VM_BUG_ON(gap < mas.index);
 	return gap;
 }
 
-- 
2.35.1