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From: Usama Arif <usama.arif@bytedance.com>
To: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
	muchun.song@linux.dev, mike.kravetz@oracle.com,
	songmuchun@bytedance.com, fam.zheng@bytedance.com,
	liangma@liangbit.com, punit.agrawal@bytedance.com,
	Usama Arif <usama.arif@bytedance.com>
Subject: [PATCH] mm: hugetlb: Only prep and add allocated folios for non-gigantic pages
Date: Mon,  9 Oct 2023 15:56:05 +0100	[thread overview]
Message-ID: <20231009145605.2150897-1-usama.arif@bytedance.com> (raw)

Calling prep_and_add_allocated_folios when allocating gigantic pages
at boot time causes the kernel to crash as folio_list is empty
and iterating it causes a NULL pointer dereference. Call this only
for non-gigantic pages when folio_list has entires.

Fixes: bfb41d6b2fe148 ("hugetlb: restructure pool allocations")
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
---
 mm/hugetlb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f3749fc125d4..b12f5fd295bb 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3397,7 +3397,8 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
 	}
 
 	/* list will be empty if hstate_is_gigantic */
-	prep_and_add_allocated_folios(h, &folio_list);
+	if (!hstate_is_gigantic(h))
+		prep_and_add_allocated_folios(h, &folio_list);
 
 	if (i < h->max_huge_pages) {
 		char buf[32];
-- 
2.25.1



             reply	other threads:[~2023-10-09 14:56 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-09 14:56 Usama Arif [this message]
2023-10-10  1:23 ` [PATCH] mm: hugetlb: Only prep and add allocated folios for non-gigantic pages Mike Kravetz
2023-10-10 17:01   ` [External] " Usama Arif
2023-10-10 21:30     ` Mike Kravetz
2023-10-10 21:31       ` Konrad Dybcio
2023-10-12  0:03   ` Nathan Chancellor
2023-10-12 14:53     ` Mike Kravetz
2023-10-13  0:12       ` Mike Kravetz
2023-10-14  0:04         ` Mike Kravetz
2023-10-18 20:54           ` Nick Desaulniers
2023-10-18 22:20             ` Mike Kravetz
2023-10-19  4:33               ` Sergey Senozhatsky
2023-10-19 14:20                 ` Nathan Chancellor
2023-10-19  2:38 ` Mike Kravetz

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