CVE-2024-43876

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> PCI: rcar: Demote WARN() to dev_warn_ratelimited() in rcar_pcie_wakeup()<br /> <br /> Avoid large backtrace, it is sufficient to warn the user that there has<br /> been a link problem. Either the link has failed and the system is in need<br /> of maintenance, or the link continues to work and user has been informed.<br /> The message from the warning can be looked up in the sources.<br /> <br /> This makes an actual link issue less verbose.<br /> <br /> First of all, this controller has a limitation in that the controller<br /> driver has to assist the hardware with transition to L1 link state by<br /> writing L1IATN to PMCTRL register, the L1 and L0 link state switching<br /> is not fully automatic on this controller.<br /> <br /> In case of an ASMedia ASM1062 PCIe SATA controller which does not support<br /> ASPM, on entry to suspend or during platform pm_test, the SATA controller<br /> enters D3hot state and the link enters L1 state. If the SATA controller<br /> wakes up before rcar_pcie_wakeup() was called and returns to D0, the link<br /> returns to L0 before the controller driver even started its transition to<br /> L1 link state. At this point, the SATA controller did send an PM_ENTER_L1<br /> DLLP to the PCIe controller and the PCIe controller received it, and the<br /> PCIe controller did set PMSR PMEL1RX bit.<br /> <br /> Once rcar_pcie_wakeup() is called, if the link is already back in L0 state<br /> and PMEL1RX bit is set, the controller driver has no way to determine if<br /> it should perform the link transition to L1 state, or treat the link as if<br /> it is in L0 state. Currently the driver attempts to perform the transition<br /> to L1 link state unconditionally, which in this specific case fails with a<br /> PMSR L1FAEG poll timeout, however the link still works as it is already<br /> back in L0 state.<br /> <br /> Reduce this warning verbosity. In case the link is really broken, the<br /> rcar_pcie_config_access() would fail, otherwise it will succeed and any<br /> system with this controller and ASM1062 can suspend without generating<br /> a backtrace.