On 2020-04-17 01:59, Jan Kara wrote: > On Thu 16-04-20 18:54:48, Christoph Hellwig wrote: >> @@ -938,7 +938,8 @@ int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args) >> if (bdi->dev) /* The driver needs to use separate queues per device */ >> return 0; >> >> - dev = device_create_vargs(bdi_class, NULL, MKDEV(0, 0), bdi, fmt, args); >> + vsnprintf(bdi->dev_name, sizeof(bdi->dev_name), fmt, args); >> + dev = device_create(bdi_class, NULL, MKDEV(0, 0), bdi, bdi->dev_name); >> if (IS_ERR(dev)) >> return PTR_ERR(dev); >> > > This can have a sideeffect not only bdi->dev_name will be truncated to 64 > chars (which generally doesn't matter) but possibly also kobject name will > be truncated in the same way. Which may have user visible effects. E.g. > for fs/vboxsf 64 chars need not be enough. So shouldn't we rather do it the > other way around - i.e., let device_create_vargs() create the device name > and then copy to bdi->dev_name whatever fits? How about using kvasprintf() instead of vsnprintf()? Thanks, Bart.
