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Merge branch 'pci/aspm'

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- Delay pcie_link_state deallocation to avoid dangling pointers that cause
  invalid references during hot-unplug (Daniel Stodden)

* pci/aspm:
  PCI/ASPM: Fix link state exit during switch upstream function removal
This commit is contained in:
Bjorn Helgaas 2025-03-27 13:14:42 -05:00
commit 2cde6eb252
1 changed files with 9 additions and 8 deletions
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17
drivers/pci/pcie/aspm.c
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@ -1273,16 +1273,16 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
parent_link = link->parent;
/*
* link->downstream is a pointer to the pci_dev of function 0. If
* we remove that function, the pci_dev is about to be deallocated,
* so we can't use link->downstream again. Free the link state to
* avoid this.
* Free the parent link state, no later than function 0 (i.e.
* link->downstream) being removed.
*
* If we're removing a non-0 function, it's possible we could
* retain the link state, but PCIe r6.0, sec 7.5.3.7, recommends
* programming the same ASPM Control value for all functions of
* multi-function devices, so disable ASPM for all of them.
* Do not free the link state any earlier. If function 0 is a
* switch upstream port, this link state is parent_link to all
* subordinate ones.
*/
if (pdev != link->downstream)
goto out;
pcie_config_aspm_link(link, 0);
list_del(&link->sibling);
free_link_state(link);
@ -1293,6 +1293,7 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
pcie_config_aspm_path(parent_link);
}
out:
mutex_unlock(&aspm_lock);
up_read(&pci_bus_sem);
}