Hello Dan Williams,
The patch b522adcde9c4: "md: 'array_size' sysfs attribute" from Mar
31, 2009, leads to the following static checker warning:
drivers/md/md.c:5069 md_run()
error: we previously assumed 'mddev->pers' could be null (see line 4936)
This code is really old. I don't know why my stupid scripts are marking
it as a new warning. We don't set "mddev->pers" to non-NULL until the
end of the function so it looks like a real bug and that "pers->size"
was intended. When I fix that bug then it un-silences this warning:
drivers/md/md.c:5080 md_run()
error: we previously assumed 'mddev->pers' could be null (see line 4936)
And that also is a real bug, but I'm not sure the right fix for that.
Basically, it's bugs all the way down from the code, to the fix, to the
static checker. *sigh*.
drivers/md/md.c
5060 err = pers->run(mddev);
5061 if (err)
5062 printk(KERN_ERR "md: pers->run() failed ...\n");
5063 else if (pers->size(mddev, 0, 0) < mddev->array_sectors) {
5064 WARN_ONCE(!mddev->external_size, "%s: default size too small,"
5065 " but 'external_size' not in effect?\n", __func__);
5066 printk(KERN_ERR
5067 "md: invalid array_size %llu > default size %llu\n",
5068 (unsigned long long)mddev->array_sectors / 2,
5069 (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
^^^^^^^^^^^^^^^^^^
This should be "pers->size()".
5070 err = -EINVAL;
5071 }
5072 if (err == 0 && pers->sync_request &&
5073 (mddev->bitmap_info.file || mddev->bitmap_info.offset)) {
5074 err = bitmap_create(mddev);
5075 if (err)
5076 printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
5077 mdname(mddev), err);
5078 }
5079 if (err) {
5080 mddev_detach(mddev);
^^^^^^^^^^^^^^^^^^^
mddev_detach() will oops if mddev->pers() is not set. We could set
mdev->pers earlier, I suppose.
5081 pers->free(mddev, mddev->private);
5082 module_put(pers->owner);
5083 bitmap_destroy(mddev);
5084 return err;
5085 }
5086 if (mddev->queue) {
5087 mddev->queue->backing_dev_info.congested_data = mddev;
5088 mddev->queue->backing_dev_info.congested_fn = md_congested;
5089 blk_queue_merge_bvec(mddev->queue, md_mergeable_bvec);
5090 }
regards,
dan carpenter
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