From: Shiju Jose <shiju.jose@xxxxxxxxxx> ghes_handle_aer() lacks synchronization with aer_recover_work_func(), so when error status data have multiple sections, aer_recover_work_func() may use estatus data for aer_capability_regs after it has been overwritten. The problem statement is here, https://lore.kernel.org/all/20230901225755.GA90053@bhelgaas/ In ghes_handle_aer() allocates memory for aer_capability_regs from the ghes_estatus_pool and copy data for aer_capability_regs from the estatus buffer. Free the memory in aer_recover_work_func() after processing the data using the ghes_estatus_pool_region_free() added. Reported-by: Bjorn Helgaas <helgaas@xxxxxxxxxx> Signed-off-by: Shiju Jose <shiju.jose@xxxxxxxxxx> --- drivers/acpi/apei/ghes.c | 23 ++++++++++++++++++++++- drivers/pci/pcie/aer.c | 10 ++++++++++ include/acpi/ghes.h | 1 + 3 files changed, 33 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index ef59d6ea16da..63ad0541db38 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -209,6 +209,20 @@ int ghes_estatus_pool_init(unsigned int num_ghes) return -ENOMEM; } +/** + * ghes_estatus_pool_region_free - free previously allocated memory + * from the ghes_estatus_pool. + * @addr: address of memory to free. + * @size: size of memory to free. + * + * Returns none. + */ +void ghes_estatus_pool_region_free(unsigned long addr, u32 size) +{ + gen_pool_free(ghes_estatus_pool, addr, size); +} +EXPORT_SYMBOL_GPL(ghes_estatus_pool_region_free); + static int map_gen_v2(struct ghes *ghes) { return apei_map_generic_address(&ghes->generic_v2->read_ack_register); @@ -564,6 +578,7 @@ static void ghes_handle_aer(struct acpi_hest_generic_data *gdata) pcie_err->validation_bits & CPER_PCIE_VALID_AER_INFO) { unsigned int devfn; int aer_severity; + u8 *aer_info; devfn = PCI_DEVFN(pcie_err->device_id.device, pcie_err->device_id.function); @@ -577,11 +592,17 @@ static void ghes_handle_aer(struct acpi_hest_generic_data *gdata) if (gdata->flags & CPER_SEC_RESET) aer_severity = AER_FATAL; + aer_info = (void *)gen_pool_alloc(ghes_estatus_pool, + sizeof(struct aer_capability_regs)); + if (!aer_info) + return; + memcpy(aer_info, pcie_err->aer_info, sizeof(struct aer_capability_regs)); + aer_recover_queue(pcie_err->device_id.segment, pcie_err->device_id.bus, devfn, aer_severity, (struct aer_capability_regs *) - pcie_err->aer_info); + aer_info); } #endif } diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c index e85ff946e8c8..388b614c11fd 100644 --- a/drivers/pci/pcie/aer.c +++ b/drivers/pci/pcie/aer.c @@ -29,6 +29,7 @@ #include <linux/kfifo.h> #include <linux/slab.h> #include <acpi/apei.h> +#include <acpi/ghes.h> #include <ras/ras_event.h> #include "../pci.h" @@ -996,6 +997,15 @@ static void aer_recover_work_func(struct work_struct *work) continue; } cper_print_aer(pdev, entry.severity, entry.regs); + /* + * Memory for aer_capability_regs(entry.regs) is being allocated from the + * ghes_estatus_pool to protect it from overwriting when multiple sections + * are present in the error status. Thus free the same after processing + * the data. + */ + ghes_estatus_pool_region_free((unsigned long)entry.regs, + sizeof(struct aer_capability_regs)); + if (entry.severity == AER_NONFATAL) pcie_do_recovery(pdev, pci_channel_io_normal, aer_root_reset); diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h index 3c8bba9f1114..40d89e161076 100644 --- a/include/acpi/ghes.h +++ b/include/acpi/ghes.h @@ -78,6 +78,7 @@ static inline struct list_head *ghes_get_devices(void) { return NULL; } #endif int ghes_estatus_pool_init(unsigned int num_ghes); +void ghes_estatus_pool_region_free(unsigned long addr, u32 size); static inline int acpi_hest_get_version(struct acpi_hest_generic_data *gdata) { -- 2.34.1
