linux-kernel - [PATCH 2/2] [PATCH 2/2] mm: add merging after mremap resize

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 27 May 2022 12:48:10 +0200
From:   Jakub Matěna <matenajakub@...il.com>
To:     akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, patches@...ts.linux.dev,
        linux-kernel@...r.kernel.org, vbabka@...e.cz, mhocko@...nel.org,
        mgorman@...hsingularity.net, willy@...radead.org,
        liam.howlett@...cle.com, hughd@...gle.com, kirill@...temov.name,
        riel@...riel.com, rostedt@...dmis.org, peterz@...radead.org,
        Jakub Matěna <matenajakub@...il.com>
Subject: [PATCH 2/2] [PATCH 2/2] mm: add merging after mremap resize

When mremap call results in expansion, it might be possible to merge the
VMA with the next VMA which might become adjacent. This patch adds
vma_merge call after the expansion is done to try and merge.

Signed-off-by: Jakub Matěna <matenajakub@...il.com>
---
 mm/mremap.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 303d3290b938..c41237e62156 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/mm.h>
+#include <linux/mm_inline.h>
 #include <linux/hugetlb.h>
 #include <linux/shm.h>
 #include <linux/ksm.h>
@@ -1022,8 +1023,11 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 				}
 			}
 
-			if (vma_adjust(vma, vma->vm_start, addr + new_len,
-				       vma->vm_pgoff, NULL)) {
+			vma = vma_merge(mm, vma, addr + old_len, addr + new_len,
+					vma->vm_flags, vma->anon_vma, vma->vm_file,
+					vma->vm_pgoff + (old_len >> PAGE_SHIFT), vma_policy(vma),
+					vma->vm_userfaultfd_ctx, anon_vma_name(vma));
+			if (!vma) {
 				vm_unacct_memory(pages);
 				ret = -ENOMEM;
 				goto out;
-- 
2.35.1