From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> mainline inclusion from mainline-v7.0-rc5 commit bf504b229cb8d534eccbaeaa23eba34c05131e25 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14870 CVE: CVE-2026-43313 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------- After commi f132e089fe89 ("ACPI: processor: Fix NULL-pointer dereference in acpi_processor_errata_piix4()"), device pointers may be dereferenced after dropping references to the device objects pointed to by them, which may cause a use-after-free to occur. Moreover, debug messages about enabling the errata may be printed if the errata flags corresponding to them are unset. Address all of these issues by moving message printing to the points in the code where the errata flags are set. Fixes: f132e089fe89 ("ACPI: processor: Fix NULL-pointer dereference in acpi_processor_errata_piix4()") Reported-by: Guenter Roeck <linux@roeck-us.net> Closes: https://lore.kernel.org/linux-acpi/938e2206-def5-4b7a-9b2c-d1fd37681d8a@roec... Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://patch.msgid.link/5975693.DvuYhMxLoT@rafael.j.wysocki Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- drivers/acpi/acpi_processor.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index 700f32e78ffd..1774850e5c45 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -102,6 +102,10 @@ static int acpi_processor_errata_piix4(struct pci_dev *dev) PCI_ANY_ID, PCI_ANY_ID, NULL); if (ide_dev) { errata.piix4.bmisx = pci_resource_start(ide_dev, 4); + if (errata.piix4.bmisx) + dev_dbg(&ide_dev->dev, + "Bus master activity detection (BM-IDE) erratum enabled\n"); + pci_dev_put(ide_dev); } @@ -120,20 +124,17 @@ static int acpi_processor_errata_piix4(struct pci_dev *dev) if (isa_dev) { pci_read_config_byte(isa_dev, 0x76, &value1); pci_read_config_byte(isa_dev, 0x77, &value2); - if ((value1 & 0x80) || (value2 & 0x80)) + if ((value1 & 0x80) || (value2 & 0x80)) { errata.piix4.fdma = 1; + dev_dbg(&isa_dev->dev, + "Type-F DMA livelock erratum (C3 disabled)\n"); + } pci_dev_put(isa_dev); } break; } - if (ide_dev) - dev_dbg(&ide_dev->dev, "Bus master activity detection (BM-IDE) erratum enabled\n"); - - if (isa_dev) - dev_dbg(&isa_dev->dev, "Type-F DMA livelock erratum (C3 disabled)\n"); - return 0; } -- 2.34.1