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Mon, 19 Oct 2026 14:31:28 -0700 (PDT) Date: Mon, 19 Oct 2026 21:30:52 +0000 In-Reply-To: <20261019213054.3157159-1-dmatlack@google.com> X-Archived-By: Mime-Version: 1.0 References: <20261019213054.3157159-1-dmatlack@google.com> X-Mailer: git-send-email 2.56.0.212.g129ede20d9-goog Message-ID: <20261019213054.3157159-9-dmatlack@google.com> Subject: [PATCH 08/10] PCI: liveupdate: Prevent releasing resource windows of incoming bridges From: David Matlack To: kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org Cc: Adithya Jayachandran , Alexander Graf , Alex Williamson , Bjorn Helgaas , David Matlack , "=?UTF-8?q?Ilpo=20J=C3=A4rvinen?=" , Jacob Pan , Jason Gunthorpe , Josh Hilke , Leon Romanovsky , Logan Gunthorpe , Lukas Wunner , Mike Rapoport , Parav Pandit , Pasha Tatashin , Pranjal Shrivastava , Pratyush Yadav , Saeed Mahameed , Samiullah Khawaja , Vipin Sharma , William Tu Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261019_143131_065103_DF5A88FC X-CRM114-Status: GOOD ( 12.08 ) X-Spam-Score: -9.5 (---------) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" X-Spam-Status: No, score=-26.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIMWL_WL_MED,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Prevent the windows of bridges preserved across Live Update from being released during the recursive "realloc" failure paths by adding a check for pci_liveupdate_is_incoming() to pci_bridge_release_resources(), and log that the window was not released, similar to the message that pci_release_resource() logs when it releases a window. This prevents the PCI core from forcibly releasing a preserved bridge window to satisfy the resource needs of a failing child device. Instead, the child's resources simply fail to be allocated. This should never happen in practice though, since the previous kernel should have established a sane resource allocation before kexec. Assisted-by: LLM Signed-off-by: David Matlack --- drivers/pci/setup-bus.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index b82440394ee2..7283c4be803e 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1700,6 +1700,12 @@ static void pci_bridge_release_resources(struct pci_bus *bus, idx = pci_resource_num(dev, b_win); + if (pci_liveupdate_is_incoming(dev)) { + pci_info(dev, "%s %pR: not releasing window of bridge preserved across Live Update\n", + pci_resource_name(dev, idx), b_win); + return; + } + /* If there are children, release them all */ release_child_resources(b_win); -- 2.56.0.212.g129ede20d9-goog