linux-kernel - [RFC v3 -next] cma: Enforce non-zero pageblock_order during cma_init_reserved

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

Message-ID: <054b416302486c2d3fdd5924b624477929100bf6.1728656994.git.ritesh.list@gmail.com>
Date: Fri, 11 Oct 2024 20:26:09 +0530
From: "Ritesh Harjani (IBM)" <ritesh.list@...il.com>
To: linux-mm@...ck.org
Cc: linuxppc-dev@...ts.ozlabs.org,
	Sourabh Jain <sourabhjain@...ux.ibm.com>,
	Hari Bathini <hbathini@...ux.ibm.com>,
	Zi Yan <ziy@...dia.com>,
	David Hildenbrand <david@...hat.com>,
	"Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
	Mahesh J Salgaonkar <mahesh@...ux.ibm.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Madhavan Srinivasan <maddy@...ux.ibm.com>,
	"Aneesh Kumar K . V" <aneesh.kumar@...nel.org>,
	Donet Tom <donettom@...ux.vnet.ibm.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Sachin P Bappalige <sachinpb@...ux.ibm.com>,
	"Ritesh Harjani (IBM)" <ritesh.list@...il.com>
Subject: [RFC v3 -next] cma: Enforce non-zero pageblock_order during cma_init_reserved_mem()

cma_init_reserved_mem() checks base and size alignment with
CMA_MIN_ALIGNMENT_BYTES. However, some users might call this during
early boot when pageblock_order is 0. That means if base and size does
not have pageblock_order alignment, it can cause functional failures
during cma activate area.

So let's enforce pageblock_order to be non-zero during
cma_init_reserved_mem().

Acked-by: David Hildenbrand <david@...hat.com>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@...il.com>
---
v2 -> v3: Separated the series into 2 as discussed in v2.
[v2]: https://lore.kernel.org/linuxppc-dev/cover.1728585512.git.ritesh.list@gmail.com/

 mm/cma.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/mm/cma.c b/mm/cma.c
index 3e9724716bad..36d753e7a0bf 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -182,6 +182,15 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 	if (!size || !memblock_is_region_reserved(base, size))
 		return -EINVAL;

+	/*
+	 * CMA uses CMA_MIN_ALIGNMENT_BYTES as alignment requirement which
+	 * needs pageblock_order to be initialized. Let's enforce it.
+	 */
+	if (!pageblock_order) {
+		pr_err("pageblock_order not yet initialized. Called during early boot?\n");
+		return -EINVAL;
+	}
+
 	/* ensure minimal alignment required by mm core */
 	if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
 		return -EINVAL;
--
2.46.0