In pcie_aspm_init_link_state(), a number of checks are made to determine whether the function should proceed, before the result of the call to pcie_aspm_sanity_check() is actually used. The latter function doesn't change any state, it only reports a result, so calling it later doesn't make any difference to the state of the devices or the information we have about them. But having the call early reportedly can cause null-pointer dereferences; see https://unix.stackexchange.com/q/322337 for one example with pcie_aspm=off (this was reported in 2016, but the relevant code hasn't changed since then). This moves the call to pcie_aspm_sanity_check() just before the result is actually used, giving all the other checks a chance to run first. Signed-off-by: Stephen Kitt <steve@xxxxxxx> --- drivers/pci/pcie/aspm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index a8aec190986c..38df439568b7 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -889,7 +889,7 @@ static void pcie_aspm_update_sysfs_visibility(struct pci_dev *pdev) void pcie_aspm_init_link_state(struct pci_dev *pdev) { struct pcie_link_state *link; - int blacklist = !!pcie_aspm_sanity_check(pdev); + int blacklist; if (!aspm_support_enabled) return; @@ -923,6 +923,7 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) * upstream links also because capable state of them can be * update through pcie_aspm_cap_init(). */ + blacklist = !!pcie_aspm_sanity_check(pdev); pcie_aspm_cap_init(link, blacklist); /* Setup initial Clock PM state */ base-commit: 833477fce7a14d43ae4c07f8ddc32fa5119471a2 -- 2.30.2
