linux-kernel - [PATCH v2] mm: add warning if __vm_enough

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-next>] [day] [month] [year] [list]

Message-ID: <20220726145428.8030-1-wangkefeng.wang@huawei.com>
Date:   Tue, 26 Jul 2022 22:54:28 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Andrew Morton <akpm@...ux-foundation.org>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>
CC:     David Hildenbrand <david@...hat.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Yongqiang Liu <liuyongqiang13@...wei.com>
Subject: [PATCH v2] mm: add warning if __vm_enough_memory fails

If a process has no enough memory to allocate a new virtual mapping, we
may meet kinds of error, eg, fork cannot allocate memory, SIGBUS error
in shmem, but it is difficult to confirm them, let's add some debug
information to easy to check this scenario if __vm_enough_memory fails.

Reported-by: Yongqiang Liu <liuyongqiang13@...wei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
v2: use pr_warn_ratelimited, suggested by David Hildenbrand

 mm/util.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/util.c b/mm/util.c
index 1266a33a49ea..c786e21c6051 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -1020,6 +1020,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
 	if (percpu_counter_read_positive(&vm_committed_as) < allowed)
 		return 0;
 error:
+	pr_warn_ratelimited("%s: pid: %d, comm: %s, no enough memory for the allocation\n",
+			    __func__, current->pid, current->comm);
 	vm_unacct_memory(pages);
 
 	return -ENOMEM;
-- 
2.35.3