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([2a09:bac6:37a8:ebe::178:143]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a0394e6c5asm60543205e9.2.2026.10.02.06.31.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Oct 2026 06:31:49 -0700 (PDT) From: Matt Fleming To: Joerg Roedel Cc: Suravee Suthikulpanit , Ashish Kalra , Vasant Hegde , Sairaj Kodilkar , Baoquan He , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@cloudflare.com, Matt Fleming Subject: [PATCH 0/2] iommu/amd: Fix device table setup in kdump kernels Date: Fri, 2 Oct 2026 14:31:41 +0100 Message-ID: <20261002133143.3628181-1-matt@readmodwrite.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Matt Fleming An AMD kdump kernel booted with crashkernel=512M,high and crashkernel=0,low fails to allocate its device table because there's no memory below 4G. IOMMU init fails and, on our systems with an Intel E810 NIC, the ice driver's TX queues time out, so the dump never gets sent. Since commit 38e5f33ee359 ("iommu/amd: Reuse device table for kdump"), a kdump kernel normally reuses the previous kernel's table. Patch 1 programs the new table if reuse fails. Patch 2 drops GFP_DMA32 for kdump kernels. Normal kernels still allocate below 4G, because that's what the kdump kernel checks before reusing the table. On an AMD EPYC system with an E810 NIC, the kdump kernel without these patches failed the order-9 GFP_DMA32 allocation and its TX queues timed out. With these patches, the kdump kernel reused the old device table and the dump was written over the network. Matt Fleming (2): iommu/amd: Program device table when kdump reuse fails iommu/amd: Don't allocate kdump device table from DMA32 drivers/iommu/amd/init.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) -- 2.43.0