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9393998e9e
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>
78 lines
2.9 KiB
Text
78 lines
2.9 KiB
Text
// SPDX-License-Identifier: GPL-2.0+
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(*
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* Copyright (C) 2015 Jade Alglave <j.alglave@ucl.ac.uk>,
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* Copyright (C) 2016 Luc Maranget <luc.maranget@inria.fr> for Inria
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* Copyright (C) 2017 Alan Stern <stern@rowland.harvard.edu>,
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* Andrea Parri <parri.andrea@gmail.com>
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*
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* An earlier version of this file appeared in the companion webpage for
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* "Frightening small children and disconcerting grown-ups: Concurrency
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* in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern,
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* which appeared in ASPLOS 2018.
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*)
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"Linux-kernel memory consistency model"
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enum Accesses = 'once (*READ_ONCE,WRITE_ONCE*) ||
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'release (*smp_store_release*) ||
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'acquire (*smp_load_acquire*) ||
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'noreturn (* R of non-return RMW *)
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instructions R[{'once,'acquire,'noreturn}]
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instructions W[{'once,'release}]
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instructions RMW[{'once,'acquire,'release}]
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enum Barriers = 'wmb (*smp_wmb*) ||
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'rmb (*smp_rmb*) ||
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'mb (*smp_mb*) ||
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'rcu-lock (*rcu_read_lock*) ||
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'rcu-unlock (*rcu_read_unlock*) ||
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'sync-rcu (*synchronize_rcu*) ||
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'before-atomic (*smp_mb__before_atomic*) ||
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'after-atomic (*smp_mb__after_atomic*) ||
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'after-spinlock (*smp_mb__after_spinlock*) ||
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'after-unlock-lock (*smp_mb__after_unlock_lock*)
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instructions F[Barriers]
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(* SRCU *)
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enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu
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instructions SRCU[SRCU]
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(* All srcu events *)
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let Srcu = Srcu-lock | Srcu-unlock | Sync-srcu
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(* Compute matching pairs of nested Rcu-lock and Rcu-unlock *)
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let rcu-rscs = let rec
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unmatched-locks = Rcu-lock \ domain(matched)
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and unmatched-unlocks = Rcu-unlock \ range(matched)
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and unmatched = unmatched-locks | unmatched-unlocks
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and unmatched-po = [unmatched] ; po ; [unmatched]
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and unmatched-locks-to-unlocks =
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[unmatched-locks] ; po ; [unmatched-unlocks]
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and matched = matched | (unmatched-locks-to-unlocks \
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(unmatched-po ; unmatched-po))
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in matched
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(* Validate nesting *)
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flag ~empty Rcu-lock \ domain(rcu-rscs) as unbalanced-rcu-locking
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flag ~empty Rcu-unlock \ range(rcu-rscs) as unbalanced-rcu-locking
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(* Compute matching pairs of nested Srcu-lock and Srcu-unlock *)
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let srcu-rscs = let rec
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unmatched-locks = Srcu-lock \ domain(matched)
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and unmatched-unlocks = Srcu-unlock \ range(matched)
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and unmatched = unmatched-locks | unmatched-unlocks
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and unmatched-po = ([unmatched] ; po ; [unmatched]) & loc
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and unmatched-locks-to-unlocks =
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([unmatched-locks] ; po ; [unmatched-unlocks]) & loc
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and matched = matched | (unmatched-locks-to-unlocks \
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(unmatched-po ; unmatched-po))
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in matched
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(* Validate nesting *)
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flag ~empty Srcu-lock \ domain(srcu-rscs) as unbalanced-srcu-locking
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flag ~empty Srcu-unlock \ range(srcu-rscs) as unbalanced-srcu-locking
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(* Check for use of synchronize_srcu() inside an RCU critical section *)
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flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep
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(* Validate SRCU dynamic match *)
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flag ~empty different-values(srcu-rscs) as srcu-bad-nesting
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