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    Subject[PATCH 1/2] of: fix race when matching drivers
    From: Milton Miller <>

    If two drivers are probing devices at the same time, both will write
    their match table result to the dev->of_match cache at the same time.

    Only write the result if the device matches.

    In a thread titled "SBus devices sometimes detected, sometimes not",
    Meelis reported his SBus hme was not detected about 50% of the time.
    >From the debug suggested by Grant it was obvious another driver matched
    some devices between the call to match the hme and the hme discovery

    Reported-by: Meelis Roos <>
    Signed-off-by: Milton Miller <>
    [grant.likely: modified to only call of_match_device() once]
    Signed-off-by: Grant Likely <>
    include/linux/of_device.h | 8 ++++++--
    1 files changed, 6 insertions(+), 2 deletions(-)

    diff --git a/include/linux/of_device.h b/include/linux/of_device.h
    index 8bfe6c1..b33d688 100644
    --- a/include/linux/of_device.h
    +++ b/include/linux/of_device.h
    @@ -21,8 +21,12 @@ extern void of_device_make_bus_id(struct device *dev);
    static inline int of_driver_match_device(struct device *dev,
    const struct device_driver *drv)
    - dev->of_match = of_match_device(drv->of_match_table, dev);
    - return dev->of_match != NULL;
    + const struct of_device_id *match;
    + match = of_match_device(drv->of_match_table, dev);
    + if (match)
    + dev->of_match = match;
    + return match != NULL;

    extern struct platform_device *of_dev_get(struct platform_device *dev);

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      Last update: 2011-05-18 21:23    [W:0.019 / U:57.424 seconds]
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