On Tue, 18 Aug 2020 at 12:11, Tingwei Zhang tingwei@codeaurora.org wrote:
Below BUG is triggered by call pm_runtime_get_sync() in cti_cpuhp_enable_hw(). It's in CPU hotplug callback with interrupt disabled. Pm_runtime_get_sync() calls clock driver to enable clock which could sleep. Remove pm_runtime_get_sync() in cti_cpuhp_enable_hw() since pm_runtime_get_sync() is called in cti_enabld and pm_runtime_put() is called in cti_disabled. No need to increase pm count when CPU gets online since it's not decreased when CPU is offline.
[ 105.800279] BUG: scheduling while atomic: swapper/1/0/0x00000002 [ 105.800290] Modules linked in: [ 105.800327] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 5.9.0-rc1-gff1304be0a05-dirty #21 [ 105.800337] Hardware name: Thundercomm Dragonboard 845c (DT) [ 105.800353] Call trace: [ 105.800414] dump_backtrace+0x0/0x1d4 [ 105.800439] show_stack+0x14/0x1c [ 105.800462] dump_stack+0xc0/0x100 [ 105.800490] __schedule_bug+0x58/0x74 [ 105.800523] __schedule+0x590/0x65c [ 105.800538] schedule+0x78/0x10c [ 105.800553] schedule_timeout+0x188/0x250 [ 105.800585] qmp_send.constprop.10+0x12c/0x1b0 [ 105.800599] qmp_qdss_clk_prepare+0x18/0x20 [ 105.800622] clk_core_prepare+0x48/0xd4 [ 105.800639] clk_prepare+0x20/0x34 [ 105.800663] amba_pm_runtime_resume+0x54/0x90 [ 105.800695] __rpm_callback+0xdc/0x138 [ 105.800709] rpm_callback+0x24/0x78 [ 105.800724] rpm_resume+0x328/0x47c [ 105.800739] __pm_runtime_resume+0x50/0x74 [ 105.800768] cti_starting_cpu+0x40/0xa4 [ 105.800795] cpuhp_invoke_callback+0x84/0x1e0 [ 105.800814] notify_cpu_starting+0x9c/0xb8 [ 105.800834] secondary_start_kernel+0xd8/0x164 [ 105.800933] CPU1: Booted secondary processor 0x0000000100 [0x517f803c]
Fixes: e9b880581d55 ("coresight: cti: Add CPU Hotplug handling to CTI driver") Signed-off-by: Tingwei Zhang tingwei@codeaurora.org
drivers/hwtracing/coresight/coresight-cti.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c index 869569eb8c7f..baba6af83440 100644 --- a/drivers/hwtracing/coresight/coresight-cti.c +++ b/drivers/hwtracing/coresight/coresight-cti.c @@ -126,9 +126,7 @@ static int cti_enable_hw(struct cti_drvdata *drvdata) static void cti_cpuhp_enable_hw(struct cti_drvdata *drvdata) { struct cti_config *config = &drvdata->config;
struct device *dev = &drvdata->csdev->dev;pm_runtime_get_sync(dev->parent); spin_lock(&drvdata->spinlock); config->hw_powered = true;@@ -148,7 +146,6 @@ static void cti_cpuhp_enable_hw(struct cti_drvdata *drvdata) /* did not re-enable due to no claim / no request */ cti_hp_not_enabled: spin_unlock(&drvdata->spinlock);
pm_runtime_put(dev->parent);}
/* disable hardware */
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Reviewed-by Mike Leach mike.leach@linaro.org