lkml.org 
[lkml]   [2013]   [Jan]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[ 002/123] firmware loader: Fix the race FW_STATUS_DONE is followed by class_timeout
    Date
    3.7-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Chuansheng Liu <chuansheng.liu@intel.com>

    commit ce2fcbd99cef580623116bb33531dbc3e6f690b0 upstream.

    There is a race as below when calling request_firmware():
    CPU1 CPU2
    write 0 > loading
    mutex_lock(&fw_lock)
    ...
    set_bit FW_STATUS_DONE class_timeout is coming
    set_bit FW_STATUS_ABORT
    complete_all &completion
    ...
    mutex_unlock(&fw_lock)

    In this time, the bit FW_STATUS_DONE and FW_STATUS_ABORT are set,
    and request_firmware() will return failure due to condition in
    _request_firmware_load():
    if (!buf->size || test_bit(FW_STATUS_ABORT, &buf->status))
    retval = -ENOENT;

    But from the above scenerio, it should be a successful requesting.
    So we need judge if the bit FW_STATUS_DONE is already set before
    calling fw_load_abort() in timeout function.

    As Ming's proposal, we need change the timer into sched_work to
    benefit from using &fw_lock mutex also.

    Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
    Acked-by: Ming Lei <ming.lei@canonical.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/base/firmware_class.c | 24 ++++++++++++++++--------
    1 file changed, 16 insertions(+), 8 deletions(-)

    --- a/drivers/base/firmware_class.c
    +++ b/drivers/base/firmware_class.c
    @@ -143,7 +143,7 @@ struct fw_cache_entry {
    };

    struct firmware_priv {
    - struct timer_list timeout;
    + struct delayed_work timeout_work;
    bool nowait;
    struct device dev;
    struct firmware_buf *buf;
    @@ -667,11 +667,18 @@ static struct bin_attribute firmware_att
    .write = firmware_data_write,
    };

    -static void firmware_class_timeout(u_long data)
    +static void firmware_class_timeout_work(struct work_struct *work)
    {
    - struct firmware_priv *fw_priv = (struct firmware_priv *) data;
    + struct firmware_priv *fw_priv = container_of(work,
    + struct firmware_priv, timeout_work.work);

    + mutex_lock(&fw_lock);
    + if (test_bit(FW_STATUS_DONE, &(fw_priv->buf->status))) {
    + mutex_unlock(&fw_lock);
    + return;
    + }
    fw_load_abort(fw_priv);
    + mutex_unlock(&fw_lock);
    }

    static struct firmware_priv *
    @@ -690,8 +697,8 @@ fw_create_instance(struct firmware *firm

    fw_priv->nowait = nowait;
    fw_priv->fw = firmware;
    - setup_timer(&fw_priv->timeout,
    - firmware_class_timeout, (u_long) fw_priv);
    + INIT_DELAYED_WORK(&fw_priv->timeout_work,
    + firmware_class_timeout_work);

    f_dev = &fw_priv->dev;

    @@ -858,7 +865,9 @@ static int _request_firmware_load(struct
    dev_dbg(f_dev->parent, "firmware: direct-loading"
    " firmware %s\n", buf->fw_id);

    + mutex_lock(&fw_lock);
    set_bit(FW_STATUS_DONE, &buf->status);
    + mutex_unlock(&fw_lock);
    complete_all(&buf->completion);
    direct_load = 1;
    goto handle_fw;
    @@ -894,15 +903,14 @@ static int _request_firmware_load(struct
    dev_set_uevent_suppress(f_dev, false);
    dev_dbg(f_dev, "firmware: requesting %s\n", buf->fw_id);
    if (timeout != MAX_SCHEDULE_TIMEOUT)
    - mod_timer(&fw_priv->timeout,
    - round_jiffies_up(jiffies + timeout));
    + schedule_delayed_work(&fw_priv->timeout_work, timeout);

    kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
    }

    wait_for_completion(&buf->completion);

    - del_timer_sync(&fw_priv->timeout);
    + cancel_delayed_work_sync(&fw_priv->timeout_work);

    handle_fw:
    mutex_lock(&fw_lock);



    \
     
     \ /
      Last update: 2013-01-09 22:01    [W:4.035 / U:0.048 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site