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    Subject[PATCH 5.4 092/260] staging: board: Fix uninitialized spinlock when attaching genpd
    Date
    From: Geert Uytterhoeven <geert+renesas@glider.be>

    [ Upstream commit df00609821bf17f50a75a446266d19adb8339d84 ]

    On Armadillo-800-EVA with CONFIG_DEBUG_SPINLOCK=y:

    BUG: spinlock bad magic on CPU#0, swapper/1
    lock: lcdc0_device+0x10c/0x308, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
    CPU: 0 PID: 1 Comm: swapper Not tainted 5.11.0-rc5-armadillo-00036-gbbca04be7a80-dirty #287
    Hardware name: Generic R8A7740 (Flattened Device Tree)
    [<c010c3c8>] (unwind_backtrace) from [<c010a49c>] (show_stack+0x10/0x14)
    [<c010a49c>] (show_stack) from [<c0159534>] (do_raw_spin_lock+0x20/0x94)
    [<c0159534>] (do_raw_spin_lock) from [<c040858c>] (dev_pm_get_subsys_data+0x8c/0x11c)
    [<c040858c>] (dev_pm_get_subsys_data) from [<c05fbcac>] (genpd_add_device+0x78/0x2b8)
    [<c05fbcac>] (genpd_add_device) from [<c0412db4>] (of_genpd_add_device+0x34/0x4c)
    [<c0412db4>] (of_genpd_add_device) from [<c0a1ea74>] (board_staging_register_device+0x11c/0x148)
    [<c0a1ea74>] (board_staging_register_device) from [<c0a1eac4>] (board_staging_register_devices+0x24/0x28)

    of_genpd_add_device() is called before platform_device_register(), as it
    needs to attach the genpd before the device is probed. But the spinlock
    is only initialized when the device is registered.

    Fix this by open-coding the spinlock initialization, cfr.
    device_pm_init_common() in the internal drivers/base code, and in the
    SuperH early platform code.

    Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
    Link: https://lore.kernel.org/r/57783ece7ddae55f2bda2f59f452180bff744ea0.1626257398.git.geert+renesas@glider.be
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/staging/board/board.c | 7 ++++++-
    1 file changed, 6 insertions(+), 1 deletion(-)

    diff --git a/drivers/staging/board/board.c b/drivers/staging/board/board.c
    index cb6feb34dd40..f980af037345 100644
    --- a/drivers/staging/board/board.c
    +++ b/drivers/staging/board/board.c
    @@ -136,6 +136,7 @@ int __init board_staging_register_clock(const struct board_staging_clk *bsc)
    static int board_staging_add_dev_domain(struct platform_device *pdev,
    const char *domain)
    {
    + struct device *dev = &pdev->dev;
    struct of_phandle_args pd_args;
    struct device_node *np;

    @@ -148,7 +149,11 @@ static int board_staging_add_dev_domain(struct platform_device *pdev,
    pd_args.np = np;
    pd_args.args_count = 0;

    - return of_genpd_add_device(&pd_args, &pdev->dev);
    + /* Initialization similar to device_pm_init_common() */
    + spin_lock_init(&dev->power.lock);
    + dev->power.early_init = true;
    +
    + return of_genpd_add_device(&pd_args, dev);
    }
    #else
    static inline int board_staging_add_dev_domain(struct platform_device *pdev,
    --
    2.30.2


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