On Fri, 12 Dec 2008, Eric Dumazet wrote: > > a truly allocated file. At this point the file is > > a truly allocated file but not anymore ours. Its a valid file. Does ownership matter here? > Reading again this mail I realise we call put_filp(file), while this should > be fput(file) or put_filp(file), we dont know. > > Damned, this patch is wrong as is. > > Christoph, Paul, do you see the problem ? Yes. > In fget()/fget_light() we dont know if the other thread (the one who re-allocated the file, > and tried to close it while we got a reference on file) had to call put_filp() or fput() > to release its own reference. So we call atomic_long_dec_and_test() and cannot > take the appropriate action (calling the full __fput() version or the small one, > that some systems use to 'close' an not really opened file. The difference is mainly that fput() does full processing whereas put_filp() is used when we know that the file was not fully operational. If the checks in __fput are able to handle the put_filp() situation by not releasing resources that were not allocated then we should be fine. > I believe put_filp() is only called on slowpath (error cases). Looks like it. It seems to assume that no dentry is associated. > Should we just zap it and always call fput() ? Only if fput() can handle partially setup files. -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
