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    Subject[PATCH 5.8 231/633] coresight: cti: remove pm_runtime_get_sync() from CPU hotplug
    Date
    From: Tingwei Zhang <tingwei@codeaurora.org>

    [ Upstream commit 6e8836c6df5327bdb24211424f1ad1411d1ed64a ]

    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")
    Reviewed-by: Mike Leach <mike.leach@linaro.org>
    Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
    Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
    Link: https://lore.kernel.org/r/20200916191737.4001561-7-mathieu.poirier@linaro.org
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.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 d6fea6efec71f..c4e9cc7034ab7 100644
    --- a/drivers/hwtracing/coresight/coresight-cti.c
    +++ b/drivers/hwtracing/coresight/coresight-cti.c
    @@ -141,9 +141,7 @@ 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;

    @@ -163,7 +161,6 @@ 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 */
    --
    2.25.1


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