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From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>,
	 David Hildenbrand <david@kernel.org>
Cc: Kiryl Shutsemau <kas@kernel.org>,
	 "Liam R. Howlett" <liam@infradead.org>,
	Lorenzo Stoakes <ljs@kernel.org>,  Michal Hocko <mhocko@suse.com>,
	Mike Rapoport <rppt@kernel.org>,
	 Suren Baghdasaryan <surenb@google.com>,
	Vlastimil Babka <vbabka@kernel.org>,
	 linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	stable@vger.kernel.org
Subject: [PATCH 1/2] mm/cma: accept memory of multi-range CMA areas
Date: Thu, 29 Oct 2026 12:18:37 +0200	[thread overview]
Message-ID: <20261029-cma-multi-v1-1-2cbced8b5cb7@kernel.org> (raw)
In-Reply-To: <20261029-cma-multi-v1-0-2cbced8b5cb7@kernel.org>

On systems with unaccepted memory, memblock allocations accept the
allocated range, but when cma_declare_contiguous_multi() uses open coded
allocation of multiple ranges, it reserves them with memblock_reserve()
and they are never accepted.

These pages are released to the buddy allocator by cma_activate_area()
with __free_pages() that does not check for unaccepted memory, so the
first access to such a page in a TDX or SEV-SNP guest is fatal.

Accept the memory of each range when it is reserved.

Fixes: c009da4258f9 ("mm, cma: support multiple contiguous ranges, if requested")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 mm/cma.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/cma.c b/mm/cma.c
index a10ea37a261da..0035efb1130a5 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -678,6 +678,8 @@ int __init cma_declare_contiguous_multi(phys_addr_t total_size,
 			break;
 		}
 
+		accept_memory(mlp->base, size);
+
 		pr_debug("created region %d: %016llx - %016llx\n",
 		    nr, (u64)mlp->base, (u64)mlp->base + size);
 		cmrp = &cma->ranges[nr++];

-- 
2.53.0



  reply	other threads:[~2026-10-29 10:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-29 10:18 [PATCH 0/2] mm/cma: accept memory of CMA areas reserved with memblock_reserve() Mike Rapoport (Microsoft)
2026-10-29 10:18 ` Mike Rapoport (Microsoft) [this message]
2026-10-29 10:52   ` [PATCH 1/2] mm/cma: accept memory of multi-range CMA areas Gupta, Pankaj
2026-10-29 12:19     ` Mike Rapoport
2026-10-29 10:18 ` [PATCH 2/2] mm/cma: accept memory of CMA areas reserved at a fixed address Mike Rapoport (Microsoft)
2026-10-29 12:27 ` [PATCH 0/2] mm/cma: accept memory of CMA areas reserved with memblock_reserve() Kiryl Shutsemau
2026-10-29 12:40   ` Mike Rapoport
2026-10-29 13:17     ` Kiryl Shutsemau
2026-10-29 15:03       ` Mike Rapoport
2026-10-29 15:39         ` Kiryl Shutsemau

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