Re: [Patch 1/2] tools/memory-model: Update some warning labels

From: Paul E. McKenney
Date: Wed Jan 25 2023 - 17:01:51 EST


On Wed, Jan 25, 2023 at 09:35:44PM +0100, Jonas Oberhauser wrote:
>
>
> On 1/25/2023 9:20 PM, Alan Stern wrote:
> > Some of the warning labels used in the LKMM are unfortunately
> > ambiguous. In particular, the same warning is used for both an
> > unmatched rcu_read_lock() call and for an unmatched rcu_read_unlock()
> > call. Likewise for the srcu_* equivalents. Also, the warning about
> > passing a wrong value to srcu_read_unlock() -- i.e., a value different
> > from the one returned by the matching srcu_read_lock() -- talks about
> > bad nesting rather than non-matching values.
> >
> > Let's update the warning labels to make their meanings more clear.
> >
> > Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
>
> Reviewed-by: Jonas Oberhauser <jonas.oberhauser@xxxxxxxxxxxxxxx>

Applied for further review and testing. I am thinking in terms of v6.4,
that is, the merge window after the upcoming one. Or does someone need
it earlier?

Thanx, Paul

> > ---
> >
> > tools/memory-model/linux-kernel.bell | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > Index: usb-devel/tools/memory-model/linux-kernel.bell
> > ===================================================================
> > --- usb-devel.orig/tools/memory-model/linux-kernel.bell
> > +++ usb-devel/tools/memory-model/linux-kernel.bell
> > @@ -53,8 +53,8 @@ let rcu-rscs = let rec
> > in matched
> > (* Validate nesting *)
> > -flag ~empty Rcu-lock \ domain(rcu-rscs) as unbalanced-rcu-locking
> > -flag ~empty Rcu-unlock \ range(rcu-rscs) as unbalanced-rcu-locking
> > +flag ~empty Rcu-lock \ domain(rcu-rscs) as unmatched-rcu-lock
> > +flag ~empty Rcu-unlock \ range(rcu-rscs) as unmatched-rcu-unlock
> > (* Compute matching pairs of nested Srcu-lock and Srcu-unlock *)
> > let srcu-rscs = let rec
> > @@ -69,14 +69,14 @@ let srcu-rscs = let rec
> > in matched
> > (* Validate nesting *)
> > -flag ~empty Srcu-lock \ domain(srcu-rscs) as unbalanced-srcu-locking
> > -flag ~empty Srcu-unlock \ range(srcu-rscs) as unbalanced-srcu-locking
> > +flag ~empty Srcu-lock \ domain(srcu-rscs) as unmatched-srcu-lock
> > +flag ~empty Srcu-unlock \ range(srcu-rscs) as unmatched-srcu-unlock
> > (* Check for use of synchronize_srcu() inside an RCU critical section *)
> > flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep
> > (* Validate SRCU dynamic match *)
> > -flag ~empty different-values(srcu-rscs) as srcu-bad-nesting
> > +flag ~empty different-values(srcu-rscs) as srcu-bad-value-match
> > (* Compute marked and plain memory accesses *)
> > let Marked = (~M) | IW | Once | Release | Acquire | domain(rmw) | range(rmw) |
>