From 6b738d3cdc28ee1223f7b73170db9040530547a0 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Wed, 4 Sep 2024 17:12:04 -0700 Subject: [PATCH] mm/damon/vaddr: protect vma traversal in __damon_va_thre_regions() with rcu read lock BugLink: https://bugs.launchpad.net/bugs/2089340 commit fb497d6db7c19c797cbd694b52d1af87c4eebcc6 upstream. Traversing VMAs of a given maple tree should be protected by rcu read lock. However, __damon_va_three_regions() is not doing the protection. Hold the lock. Link: https://lkml.kernel.org/r/20240905001204.1481-1-sj@kernel.org Fixes: d0cf3dd47f0d ("damon: convert __damon_va_three_regions to use the VMA iterator") Signed-off-by: Liam R. Howlett Signed-off-by: SeongJae Park Reported-by: Guenter Roeck Closes: https://lore.kernel.org/b83651a0-5b24-4206-b860-cb54ffdf209b@roeck-us.net Tested-by: Guenter Roeck Cc: David Hildenbrand Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman Signed-off-by: Portia Stephens Signed-off-by: Stefan Bader --- mm/damon/vaddr.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index 381559e4a1fa..26877b290de6 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -126,6 +126,7 @@ static int __damon_va_three_regions(struct mm_struct *mm, * If this is too slow, it can be optimised to examine the maple * tree gaps. */ + rcu_read_lock(); for_each_vma(vmi, vma) { unsigned long gap; @@ -146,6 +147,7 @@ static int __damon_va_three_regions(struct mm_struct *mm, next: prev = vma; } + rcu_read_unlock(); if (!sz_range(&second_gap) || !sz_range(&first_gap)) return -EINVAL;