linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Wei Yang <richard.weiyang@linux.alibaba.com>
To: mike.kravetz@oracle.com, akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Wei Yang <richard.weiyang@linux.alibaba.com>
Subject: [PATCH 02/10] mm/hugetlb: make sure to get NULL when list is empty
Date: Fri,  7 Aug 2020 17:12:43 +0800	[thread overview]
Message-ID: <20200807091251.12129-3-richard.weiyang@linux.alibaba.com> (raw)
In-Reply-To: <20200807091251.12129-1-richard.weiyang@linux.alibaba.com>

list_first_entry() may not return NULL even when the list is empty.

Let's make sure the behavior by using list_first_entry_or_null(),
otherwise it would corrupt the list.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
---
 mm/hugetlb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 62ec74f6d03f..0a2f3851b828 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -237,7 +237,8 @@ get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
 	VM_BUG_ON(resv->region_cache_count <= 0);
 
 	resv->region_cache_count--;
-	nrg = list_first_entry(&resv->region_cache, struct file_region, link);
+	nrg = list_first_entry_or_null(&resv->region_cache,
+			struct file_region, link);
 	VM_BUG_ON(!nrg);
 	list_del(&nrg->link);
 
-- 
2.20.1 (Apple Git-117)



  parent reply	other threads:[~2020-08-07  9:14 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-07  9:12 [PATCH 00/10] mm/hugetlb: code refine and simplification Wei Yang
2020-08-07  9:12 ` [PATCH 01/10] mm/hugetlb: not necessary to coalesce regions recursively Wei Yang
2020-08-07 12:47   ` Baoquan He
2020-08-10 20:22   ` Mike Kravetz
2020-08-07  9:12 ` Wei Yang [this message]
2020-08-07 12:49   ` [PATCH 02/10] mm/hugetlb: make sure to get NULL when list is empty Baoquan He
2020-08-07 14:28     ` Wei Yang
2020-08-10  0:57       ` Baoquan He
2020-08-10 20:28       ` Mike Kravetz
2020-08-10 23:05         ` Wei Yang
2020-08-07  9:12 ` [PATCH 03/10] mm/hugetlb: use list_splice to merge two list at once Wei Yang
2020-08-07 12:53   ` Baoquan He
2020-08-10 21:07   ` Mike Kravetz
2020-08-07  9:12 ` [PATCH 04/10] mm/hugetlb: count file_region to be added when regions_needed != NULL Wei Yang
2020-08-07 12:54   ` Baoquan He
2020-08-10 21:46   ` Mike Kravetz
2020-08-07  9:12 ` [PATCH 05/10] mm/hugetlb: remove the redundant check on non_swap_entry() Wei Yang
2020-08-07 12:55   ` Baoquan He
2020-08-07 14:28     ` Wei Yang
2020-08-07  9:12 ` [PATCH 06/10] mm/hugetlb: remove redundant huge_pte_alloc() in hugetlb_fault() Wei Yang
2020-08-07 12:59   ` Baoquan He
2020-08-10 22:00   ` Mike Kravetz
2020-08-07  9:12 ` [PATCH 07/10] mm/hugetlb: a page from buddy is not on any list Wei Yang
2020-08-07 13:06   ` Baoquan He
2020-08-10 22:25   ` Mike Kravetz
2020-08-07  9:12 ` [PATCH 08/10] mm/hugetlb: return non-isolated page in the loop instead of break and check Wei Yang
2020-08-07 13:09   ` Baoquan He
2020-08-07 14:32     ` Wei Yang
2020-08-10 22:55   ` Mike Kravetz
2020-08-07  9:12 ` [PATCH 09/10] mm/hugetlb: narrow the hugetlb_lock protection area during preparing huge page Wei Yang
2020-08-07 13:12   ` Baoquan He
2020-08-10 23:02   ` Mike Kravetz
2020-08-07  9:12 ` [PATCH 10/10] mm/hugetlb: not necessary to abuse temporary page to workaround the nasty free_huge_page Wei Yang
2020-08-10  2:17   ` Baoquan He
2020-08-11  0:19     ` Mike Kravetz
2020-08-11  1:51       ` Baoquan He
2020-08-11  6:54         ` Michal Hocko
2020-08-11 21:43           ` Mike Kravetz
2020-08-11 23:19             ` Wei Yang
2020-08-11 23:25               ` Mike Kravetz
2020-08-12  5:40             ` Baoquan He
2020-08-13 11:46             ` Michal Hocko
2020-08-17  3:04               ` Wei Yang
2020-08-11 23:55           ` Baoquan He
2020-08-07 22:25 ` [PATCH 00/10] mm/hugetlb: code refine and simplification Mike Kravetz

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200807091251.12129-3-richard.weiyang@linux.alibaba.com \
    --to=richard.weiyang@linux.alibaba.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mike.kravetz@oracle.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).