From 3c70ec71abdaf4e4fa48cd8fdfbbd864d78235a8 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 12 Jun 2025 12:20:43 -0700 Subject: [PATCH] cxl/ras: Fix CPER handler device confusion By inspection, cxl_cper_handle_prot_err() is making a series of fragile assumptions that can lead to crashes: 1/ It assumes that endpoints identified in the record are a CXL-type-3 device, nothing guarantees that. 2/ It assumes that the device is bound to the cxl_pci driver, nothing guarantees that. 3/ Minor, it holds the device lock over the switch-port tracing for no reason as the trace is 100% generated from data in the record. Correct those by checking that the PCIe endpoint parents a cxl_memdev before assuming the format of the driver data, and move the lock to where it is required. Consequently this also makes the implementation ready for CXL accelerators that are not bound to cxl_pci. Fixes: 36f257e3b0ba ("acpi/ghes, cxl/pci: Process CXL CPER Protocol Errors") Cc: Terry Bowman Cc: Li Ming Cc: Alison Schofield Cc: Ira Weiny Cc: Tony Luck Reviewed-by: Smita Koralahalli Reviewed-by: Dave Jiang Signed-off-by: Dan Williams Reviewed-by: Jonathan Cameron Reviewed-by: Li Ming Link: https://patch.msgid.link/20250612192043.2254617-1-dan.j.williams@intel.com Signed-off-by: Dave Jiang --- drivers/cxl/core/ras.c | 47 ++++++++++++++++++++++++------------------ 1 file changed, 27 insertions(+), 20 deletions(-) diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c index 485a831695c7..2731ba3a0799 100644 --- a/drivers/cxl/core/ras.c +++ b/drivers/cxl/core/ras.c @@ -31,40 +31,38 @@ static void cxl_cper_trace_uncorr_port_prot_err(struct pci_dev *pdev, ras_cap.header_log); } -static void cxl_cper_trace_corr_prot_err(struct pci_dev *pdev, - struct cxl_ras_capability_regs ras_cap) +static void cxl_cper_trace_corr_prot_err(struct cxl_memdev *cxlmd, + struct cxl_ras_capability_regs ras_cap) { u32 status = ras_cap.cor_status & ~ras_cap.cor_mask; - struct cxl_dev_state *cxlds; - cxlds = pci_get_drvdata(pdev); - if (!cxlds) - return; - - trace_cxl_aer_correctable_error(cxlds->cxlmd, status); + trace_cxl_aer_correctable_error(cxlmd, status); } -static void cxl_cper_trace_uncorr_prot_err(struct pci_dev *pdev, - struct cxl_ras_capability_regs ras_cap) +static void +cxl_cper_trace_uncorr_prot_err(struct cxl_memdev *cxlmd, + struct cxl_ras_capability_regs ras_cap) { u32 status = ras_cap.uncor_status & ~ras_cap.uncor_mask; - struct cxl_dev_state *cxlds; u32 fe; - cxlds = pci_get_drvdata(pdev); - if (!cxlds) - return; - if (hweight32(status) > 1) fe = BIT(FIELD_GET(CXL_RAS_CAP_CONTROL_FE_MASK, ras_cap.cap_control)); else fe = status; - trace_cxl_aer_uncorrectable_error(cxlds->cxlmd, status, fe, + trace_cxl_aer_uncorrectable_error(cxlmd, status, fe, ras_cap.header_log); } +static int match_memdev_by_parent(struct device *dev, const void *uport) +{ + if (is_cxl_memdev(dev) && dev->parent == uport) + return 1; + return 0; +} + static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data) { unsigned int devfn = PCI_DEVFN(data->prot_err.agent_addr.device, @@ -73,13 +71,12 @@ static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data) pci_get_domain_bus_and_slot(data->prot_err.agent_addr.segment, data->prot_err.agent_addr.bus, devfn); + struct cxl_memdev *cxlmd; int port_type; if (!pdev) return; - guard(device)(&pdev->dev); - port_type = pci_pcie_type(pdev); if (port_type == PCI_EXP_TYPE_ROOT_PORT || port_type == PCI_EXP_TYPE_DOWNSTREAM || @@ -92,10 +89,20 @@ static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data) return; } + guard(device)(&pdev->dev); + if (!pdev->dev.driver) + return; + + struct device *mem_dev __free(put_device) = bus_find_device( + &cxl_bus_type, NULL, pdev, match_memdev_by_parent); + if (!mem_dev) + return; + + cxlmd = to_cxl_memdev(mem_dev); if (data->severity == AER_CORRECTABLE) - cxl_cper_trace_corr_prot_err(pdev, data->ras_cap); + cxl_cper_trace_corr_prot_err(cxlmd, data->ras_cap); else - cxl_cper_trace_uncorr_prot_err(pdev, data->ras_cap); + cxl_cper_trace_uncorr_prot_err(cxlmd, data->ras_cap); } static void cxl_cper_prot_err_work_fn(struct work_struct *work) -- 2.50.1