torvalds/linux
3
0
Fork 0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-03-22 07:27:12 +08:00
Code Issues Packages Projects Releases Wiki Activity

ACPI: processor: Fix previous acpi_processor_errata_piix4() fix

Browse Source 
After commi f132e089fe ("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: f132e089fe ("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@roeck-us.net/
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
This commit is contained in:
Rafael J. Wysocki
2026-03-17 21:39:05 +01:00
parent f338e77383
commit bf504b229c
1 changed files with 8 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/acpi/acpi_processor.c
View File

@@ -113,6 +113,10 @@ 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);
}
@@ -131,20 +135,17 @@ 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;
}