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    SubjectRe: [PATCH v5 09/13] PCI: Introduce /sys/bus/pci/devices/.../remove
    * Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>:
    >
    > I still have the following kernel error messages in testing with your
    > latest set of patches (Jesse's linux-next). The test case is removing
    > e1000e device or its parent bridge by "echo 1 > /sys/bus/pci/devices/
    > .../remove".
    >
    > [ 537.379995] =============================================
    > [ 537.380124] [ INFO: possible recursive locking detected ]
    > [ 537.380128] 2.6.29-rc8-kk #1
    > [ 537.380128] ---------------------------------------------
    > [ 537.380128] events/4/56 is trying to acquire lock:
    > [ 537.380128] (events){--..}, at: [<ffffffff80257fc0>] flush_workqueue+0x0/0xa0
    > [ 537.380128]
    > [ 537.380128] but task is already holding lock:
    > [ 537.380128] (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
    > [ 537.380128]
    > [ 537.380128] other info that might help us debug this:
    > [ 537.380128] 3 locks held by events/4/56:
    > [ 537.380128] #0: (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
    > [ 537.380128] #1: (&ss->work){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
    > [ 537.380128] #2: (pci_remove_rescan_mutex){--..}, at: [<ffffffff803c10d1>] remove_callback+0x21/0x40

    I still cannot reproduce this lockdep issue, even using your
    .config with an e1000e device on an x86_64 kernel. :(

    I tried removing the endpoint, an intermediate bridge device, and
    the parent bus. I don't know what I'm doing wrong...

    Can you please try this patch though, and see if it fixes the
    warning? It applies on top of my other sysfs patch that
    introduces a mutex in sysfs_schedule_callback.

    Thanks.

    /ac

    diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
    index 289c43a..7cc4dc0 100644
    --- a/fs/sysfs/file.c
    +++ b/fs/sysfs/file.c
    @@ -667,6 +667,7 @@ struct sysfs_schedule_callback_struct {
    struct work_struct work;
    };

    +static struct workqueue_struct *sysfs_workqueue;
    static DEFINE_MUTEX(sysfs_workq_mutex);
    static LIST_HEAD(sysfs_workq);
    static void sysfs_schedule_callback_work(struct work_struct *work)
    @@ -720,6 +721,12 @@ int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
    }
    mutex_unlock(&sysfs_workq_mutex);

    + if (sysfs_workqueue == NULL) {
    + sysfs_workqueue = create_workqueue("sysfsqueue");
    + if (sysfs_workqueue == NULL)
    + return -ENOMEM;
    + }
    +
    ss = kmalloc(sizeof(*ss), GFP_KERNEL);
    if (!ss) {
    module_put(owner);
    @@ -735,7 +742,7 @@ int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
    mutex_lock(&sysfs_workq_mutex);
    list_add_tail(&ss->workq_list, &sysfs_workq);
    mutex_unlock(&sysfs_workq_mutex);
    - schedule_work(&ss->work);
    + queue_work(sysfs_workqueue, &ss->work);
    return 0;
    }
    EXPORT_SYMBOL_GPL(sysfs_schedule_callback);

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      Last update: 2009-03-24 20:33    [W:0.054 / U:1.192 seconds]
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