linux/tools/memory-model/linux-kernel.bell
Luc Maranget 9393998e9e tools/memory-model: Dynamically check SRCU lock-to-unlock matching
This commit checks that the return value of srcu_read_lock() is passed
to the matching srcu_read_unlock(), where "matching" is determined by
nesting.  This check operates as follows:

   1. srcu_read_lock() creates an integer token, which is stored into
      the generated events.
   2. srcu_read_unlock() records its second (token) argument into the
      generated event.
   3. A new herd primitive 'different-values' filters out pairs of events
      with identical values from the relation passed as its argument.
   4. The bell file applies the above primitive to the (srcu)
      read-side-critical-section relation 'srcu-rscs' and flags non-empty
      results.

BEWARE: Works only with herd version 7.51+6 and onwards.

Signed-off-by: Luc Maranget <Luc.Maranget@inria.fr>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
[ paulmck: Apply Andrea Parri's off-list feedback. ]
Acked-by: Alan Stern <stern@rowland.harvard.edu>
2019-03-18 10:27:52 -07:00

79 lines
2.9 KiB
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// SPDX-License-Identifier: GPL-2.0+
(*
* Copyright (C) 2015 Jade Alglave <j.alglave@ucl.ac.uk>,
* Copyright (C) 2016 Luc Maranget <luc.maranget@inria.fr> for Inria
* Copyright (C) 2017 Alan Stern <stern@rowland.harvard.edu>,
* Andrea Parri <parri.andrea@gmail.com>
*
* An earlier version of this file appeared in the companion webpage for
* "Frightening small children and disconcerting grown-ups: Concurrency
* in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern,
* which appeared in ASPLOS 2018.
*)
"Linux-kernel memory consistency model"
enum Accesses = 'once (*READ_ONCE,WRITE_ONCE*) ||
'release (*smp_store_release*) ||
'acquire (*smp_load_acquire*) ||
'noreturn (* R of non-return RMW *)
instructions R[{'once,'acquire,'noreturn}]
instructions W[{'once,'release}]
instructions RMW[{'once,'acquire,'release}]
enum Barriers = 'wmb (*smp_wmb*) ||
'rmb (*smp_rmb*) ||
'mb (*smp_mb*) ||
'rcu-lock (*rcu_read_lock*) ||
'rcu-unlock (*rcu_read_unlock*) ||
'sync-rcu (*synchronize_rcu*) ||
'before-atomic (*smp_mb__before_atomic*) ||
'after-atomic (*smp_mb__after_atomic*) ||
'after-spinlock (*smp_mb__after_spinlock*) ||
'after-unlock-lock (*smp_mb__after_unlock_lock*)
instructions F[Barriers]
(* SRCU *)
enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu
instructions SRCU[SRCU]
(* All srcu events *)
let Srcu = Srcu-lock | Srcu-unlock | Sync-srcu
(* Compute matching pairs of nested Rcu-lock and Rcu-unlock *)
let rcu-rscs = let rec
unmatched-locks = Rcu-lock \ domain(matched)
and unmatched-unlocks = Rcu-unlock \ range(matched)
and unmatched = unmatched-locks | unmatched-unlocks
and unmatched-po = [unmatched] ; po ; [unmatched]
and unmatched-locks-to-unlocks =
[unmatched-locks] ; po ; [unmatched-unlocks]
and matched = matched | (unmatched-locks-to-unlocks \
(unmatched-po ; unmatched-po))
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
(* Compute matching pairs of nested Srcu-lock and Srcu-unlock *)
let srcu-rscs = let rec
unmatched-locks = Srcu-lock \ domain(matched)
and unmatched-unlocks = Srcu-unlock \ range(matched)
and unmatched = unmatched-locks | unmatched-unlocks
and unmatched-po = ([unmatched] ; po ; [unmatched]) & loc
and unmatched-locks-to-unlocks =
([unmatched-locks] ; po ; [unmatched-unlocks]) & loc
and matched = matched | (unmatched-locks-to-unlocks \
(unmatched-po ; unmatched-po))
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
(* 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