Linux PCI subsystem development
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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Bjorn Helgaas <bhelgaas@google.com>, Hans de Goede <hdegoede@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	linux-pci@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] x86/PCI: Fix use after free in pci_acpi_root_prepare_resources()
Date: Tue, 1 Mar 2022 11:10:10 +0300	[thread overview]
Message-ID: <20220301081010.GA17375@kili> (raw)

The resource_list_destroy_entry() function frees "entry", so move the
dereferences before the free.

Fixes: 62fabd56faaf ("x86/PCI: Disable exclusion of E820 reserved addresses in some cases")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 arch/x86/pci/acpi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index e4617df661a9..fa89ffba2e51 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -357,14 +357,14 @@ static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
 	status = acpi_pci_probe_root_resources(ci);
 	if (pci_use_crs) {
 		resource_list_for_each_entry_safe(entry, tmp, &ci->resources) {
-			if (resource_is_pcicfg_ioport(entry->res))
-				resource_list_destroy_entry(entry);
 			if (resource_is_efi_mmio_region(entry->res)) {
 				dev_info(&device->dev,
 					"host bridge window %pR is marked by EFI as MMIO\n",
 					entry->res);
 				pci_use_e820 = false;
 			}
+			if (resource_is_pcicfg_ioport(entry->res))
+				resource_list_destroy_entry(entry);
 		}
 		return status;
 	}
-- 
2.20.1


             reply	other threads:[~2022-03-01  8:10 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-01  8:10 Dan Carpenter [this message]
2022-03-01 11:22 ` [PATCH] x86/PCI: Fix use after free in pci_acpi_root_prepare_resources() Hans de Goede

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