> > The current state is that both question are to be answered with "no", > i.e. debugfs file removal is racy. >
Ouch! :-(. Thanks for confirming! Somewhat related, is my understanding correct that the behaviour of character device layer w.r.t. the two questions that I asked the answer to my questions would be "yes"? i.e. cdev_del() would wait >> (1) until all the currently executing file operation methods >> (read/write/map etc) have returned? AND >> (2) until the user has given up all references (descriptors) to the >> files (i.e. until release() method has been >> called)? Thanks, Rajat On Mon, Dec 28, 2015 at 12:42 PM, Nicolai Stange <[email protected]> wrote: > Hi Rajat, > > Rajat Jain <[email protected]> writes: > >> Hi, >> >> I wanted to understand the behavior taken when a module calls >> debugfs_remove_recursive() on a directory, while files under that >> directory may still be in use by the userspace (for instance an >> ongoing read / write operation). >> >> Does the function wait >> >> (1) until all the currently executing file operation methods >> (read/write/map etc) have returned? >> OR >> (2) until the user has given up all references (descriptors) to the >> files under the directory (i.e. until release() method has been >> called)? > > The current state is that both question are to be answered with "no", > i.e. debugfs file removal is racy. > > I've recently sent a patch addressing this issue: > https://lkml.kernel.org/g/[email protected] > > Basically, it turns the answer to your first question into "yes". > Subsequent reads/writes will return a -EIO. > > That patch (series) is still under review though. > > Further reference can be found in the *sub*-thread rooted at > http://thread.gmane.org/gmane.linux.kernel/1452470/focus=1467314 > > Best, > > Nicolai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
