Messages in this thread | | | Date | Mon, 13 Jan 2003 13:42:33 +0530 | From | Dipankar Sarma <> | Subject | Re: Fixing the tty layer was Re: any chance of 2.6.0-test*? |
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On Mon, Jan 13, 2003 at 08:25:39AM +0100, Andi Kleen wrote: > > Oh, yes, I have spent hours and hours trying to untangle tty locking > > and it isn't simple. > > Oops. Could you quickly summarize your findings so far ?
I only found more confusions - I can't figure how tty_files list is locked - sure files_lock is supposed to protect it but there are deletions done without any lock. Another thing that needs looking into is to avoid or reduce use of the tasklist_lock there.
> > What does that BKL protect ? I can't seem to ever figure our if > > all the races are plugged or not. > > Well, one has to start somewhere. Just starting by plugging most of the > obvious races, then the more subtle ones can be attacked later. > > The idea of the BKL was to protect the protect context code against > itself (code lock) and also the few global data structures that > are only accessed from process context (like the tty drivers list)
In that case would it not be better to replace all BKLs by a single tty lock ?
> > I attached my current patch, it isn't too well tested however and needs > more work. > > Mostly just adds lock_kernel()s to the high level code so far and a few comments.
Cool, I will start off by testing this stuff.
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