On Wed, Apr 29, 2020 at 09:42:39PM +1000, Michael Ellerman wrote: > Christoph Hellwig <h...@lst.de> writes: > > On Tue, Apr 28, 2020 at 09:48:11PM +1000, Michael Ellerman wrote: > >> > >> This comes from fcheck_files() via fcheck(). > >> > >> It's pretty clearly documented that fcheck() must be wrapped with > >> rcu_read_lock(), so fix it. > > > > But for this to actually be useful you'd need the rcu read lock until > > your are done with the file (or got a reference). > > Hmm OK. My reasoning was that we were done with the struct file, because > we return the ctx that's hanging off the inode. > > + ctx = SPUFS_I(file_inode(file))->i_ctx; > > But I guess the lifetime of the ctx is not guaranteed if the file goes > away. > > It looks like the only long lived reference on the ctx is the one > taken in spufs_new_file() and dropped in spufs_evict_inode(). > > So if we take a reference to the ctx with the RCU lock held we should be > safe, I think. But I've definitely exhausted my spufs/vfs knowledge at > this point. > > Something like below.
Looks reasonable.