linux-kernel - [PATCH v4 07/11] riscv: mm: Take memory hotplug read-lock during kernel page table dump

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20240605114100.315918-8-bjorn@kernel.org>
Date: Wed,  5 Jun 2024 13:40:50 +0200
From: Björn Töpel <bjorn@...nel.org>
To: Alexandre Ghiti <alexghiti@...osinc.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	David Hildenbrand <david@...hat.com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Paul Walmsley <paul.walmsley@...ive.com>,
	linux-riscv@...ts.infradead.org,
	Oscar Salvador <osalvador@...e.de>
Cc: Björn Töpel <bjorn@...osinc.com>,
	Andrew Bresticker <abrestic@...osinc.com>,
	Chethan Seshadri <Chethan.Seshadri@...alinasystems.io>,
	Lorenzo Stoakes <lstoakes@...il.com>,
	Santosh Mamila <santosh.mamila@...alinasystems.io>,
	Sivakumar Munnangi <siva.munnangi@...alinasystems.io>,
	Sunil V L <sunilvl@...tanamicro.com>,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	virtualization@...ts.linux-foundation.org
Subject: [PATCH v4 07/11] riscv: mm: Take memory hotplug read-lock during kernel page table dump

From: Björn Töpel <bjorn@...osinc.com>

During memory hot remove, the ptdump functionality can end up touching
stale data. Avoid any potential crashes (or worse), by holding the
memory hotplug read-lock while traversing the page table.

This change is analogous to arm64's commit bf2b59f60ee1 ("arm64/mm:
Hold memory hotplug lock while walking for kernel page table dump").

Reviewed-by: David Hildenbrand <david@...hat.com>
Reviewed-by: Oscar Salvador <osalvador@...e.de>
Signed-off-by: Björn Töpel <bjorn@...osinc.com>
---
 arch/riscv/mm/ptdump.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c
index 1289cc6d3700..9d5f657a251b 100644
--- a/arch/riscv/mm/ptdump.c
+++ b/arch/riscv/mm/ptdump.c
@@ -6,6 +6,7 @@
 #include <linux/efi.h>
 #include <linux/init.h>
 #include <linux/debugfs.h>
+#include <linux/memory_hotplug.h>
 #include <linux/seq_file.h>
 #include <linux/ptdump.h>
 
@@ -370,7 +371,9 @@ bool ptdump_check_wx(void)
 
 static int ptdump_show(struct seq_file *m, void *v)
 {
+	get_online_mems();
 	ptdump_walk(m, m->private);
+	put_online_mems();
 
 	return 0;
 }
-- 
2.43.0