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PCI: Prevent restoring assigned resources

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restore_dev_resource() copies saved addresses and flags from the struct
pci_dev_resource back to the struct resource, typically, during rollback
from a failure or in preparation for a retry attempt.

If the resource is within resource tree, the resource must not be
modified as the resource tree could be corrupted. Thus, it's a bug to
call restore_dev_resource() for assigned resources (which did happen
due to logic flaws in the BAR resize rollback).

Add WARN_ON_ONCE() into restore_dev_resource() to detect such bugs easily
and return without altering the resource to prevent corruption.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org> # AVA, AMD GPU
Link: https://patch.msgid.link/20251113162628.5946-12-ilpo.jarvinen@linux.intel.com
This commit is contained in:
Ilpo Järvinen
2025-11-13 18:26:28 +02:00
committed by Bjorn Helgaas
parent db92e3fef5
commit 7409c1b12c
1 changed files with 4 additions and 0 deletions
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4
drivers/pci/setup-bus.c
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@@ -15,6 +15,7 @@
*/
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -135,6 +136,9 @@ static void restore_dev_resource(struct pci_dev_resource *dev_res)
{
struct resource *res = dev_res->res;
if (WARN_ON_ONCE(res->parent))
return;
res->start = dev_res->start;
res->end = dev_res->end;
res->flags = dev_res->flags;