| Message ID | 20230201101559.15529-1-johan+linaro@kernel.org |
|---|---|
| Headers | show |
| Series | interconnect: fix racy provider registration | expand |
On 01/02/2023 11:15, Johan Hovold wrote: > The current interconnect provider interface is inherently racy as > providers are expected to be registered before being fully initialised. > > This can specifically cause racing DT lookups to fail as I recently > noticed when the Qualcomm cpufreq driver failed to probe: > > of_icc_xlate_onecell: invalid index 0 > cpu cpu0: error -EINVAL: error finding src node > cpu cpu0: dev_pm_opp_of_find_icc_paths: Unable to get path0: -22 > qcom-cpufreq-hw: probe of 18591000.cpufreq failed with error -22 > > This only happens very rarely, but the bug is easily reproduced by > increasing the race window by adding an msleep() after registering > osm-l3 interconnect provider. > > Note that the Qualcomm cpufreq driver is especially susceptible to this > race as the interconnect path is looked up from the CPU nodes so that > driver core does not guarantee the probe order even when device links > are enabled (which they not always are). > > This series adds a new interconnect provider registration API which is > used to fix up the interconnect drivers before removing the old racy > API. > So is there a dependency or not? Can you make it clear that I shouldn't take memory controller bits? Best regards, Krzysztof
On Thu, Feb 02, 2023 at 12:13:33PM +0100, Krzysztof Kozlowski wrote: > On 01/02/2023 11:15, Johan Hovold wrote: > > The current interconnect provider interface is inherently racy as > > providers are expected to be registered before being fully initialised. > > > > This can specifically cause racing DT lookups to fail as I recently > > noticed when the Qualcomm cpufreq driver failed to probe: > > > > of_icc_xlate_onecell: invalid index 0 > > cpu cpu0: error -EINVAL: error finding src node > > cpu cpu0: dev_pm_opp_of_find_icc_paths: Unable to get path0: -22 > > qcom-cpufreq-hw: probe of 18591000.cpufreq failed with error -22 > > > > This only happens very rarely, but the bug is easily reproduced by > > increasing the race window by adding an msleep() after registering > > osm-l3 interconnect provider. > > > > Note that the Qualcomm cpufreq driver is especially susceptible to this > > race as the interconnect path is looked up from the CPU nodes so that > > driver core does not guarantee the probe order even when device links > > are enabled (which they not always are). > > > > This series adds a new interconnect provider registration API which is > > used to fix up the interconnect drivers before removing the old racy > > API. > > > > So is there a dependency or not? Can you make it clear that I shouldn't > take memory controller bits? As the fixes depend on the new API it is best if these could all go through Georgi's tree. Johan
The current interconnect provider interface is inherently racy as providers are expected to be registered before being fully initialised. This can specifically cause racing DT lookups to fail as I recently noticed when the Qualcomm cpufreq driver failed to probe: of_icc_xlate_onecell: invalid index 0 cpu cpu0: error -EINVAL: error finding src node cpu cpu0: dev_pm_opp_of_find_icc_paths: Unable to get path0: -22 qcom-cpufreq-hw: probe of 18591000.cpufreq failed with error -22 This only happens very rarely, but the bug is easily reproduced by increasing the race window by adding an msleep() after registering osm-l3 interconnect provider. Note that the Qualcomm cpufreq driver is especially susceptible to this race as the interconnect path is looked up from the CPU nodes so that driver core does not guarantee the probe order even when device links are enabled (which they not always are). This series adds a new interconnect provider registration API which is used to fix up the interconnect drivers before removing the old racy API. Included are also a number of fixes for other bugs found while preparing the series. Johan Johan Hovold (23): interconnect: fix mem leak when freeing nodes interconnect: fix icc_provider_del() error handling interconnect: fix provider registration API interconnect: imx: fix registration race interconnect: qcom: osm-l3: fix registration race interconnect: qcom: rpm: fix probe child-node error handling interconnect: qcom: rpm: fix probe PM domain error handling interconnect: qcom: rpm: fix registration race interconnect: qcom: rpmh: fix probe child-node error handling interconnect: qcom: rpmh: fix registration race interconnect: qcom: msm8974: fix registration race interconnect: qcom: sm8450: fix registration race interconnect: qcom: sm8550: fix registration race interconnect: exynos: fix node leak in probe PM QoS error path interconnect: exynos: fix registration race interconnect: exynos: drop redundant link destroy memory: tegra: fix interconnect registration race memory: tegra124-emc: fix interconnect registration race memory: tegra20-emc: fix interconnect registration race memory: tegra30-emc: fix interconnect registration race interconnect: drop racy registration API interconnect: drop unused icc_get() interface interconnect: drop unused icc_link_destroy() interface drivers/interconnect/core.c | 149 +++++--------------------- drivers/interconnect/imx/imx.c | 20 ++-- drivers/interconnect/qcom/icc-rpm.c | 33 +++--- drivers/interconnect/qcom/icc-rpmh.c | 30 ++++-- drivers/interconnect/qcom/msm8974.c | 20 ++-- drivers/interconnect/qcom/osm-l3.c | 14 ++- drivers/interconnect/qcom/sm8450.c | 22 ++-- drivers/interconnect/qcom/sm8550.c | 22 ++-- drivers/interconnect/samsung/exynos.c | 30 +++--- drivers/memory/tegra/mc.c | 16 ++- drivers/memory/tegra/tegra124-emc.c | 12 +-- drivers/memory/tegra/tegra20-emc.c | 12 +-- drivers/memory/tegra/tegra30-emc.c | 12 +-- include/linux/interconnect-provider.h | 19 ++-- include/linux/interconnect.h | 8 -- 15 files changed, 154 insertions(+), 265 deletions(-)