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0031e38adf
This patch adds data-race detection to the Linux-Kernel Memory Model. As part of this effort, support is added for: compiler barriers (the barrier() function), and a new Preserved Program Order term: (addr ; [Plain] ; wmb) Data races are marked with a special Flag warning in herd. It is not guaranteed that the model will provide accurate predictions when a data race is present. The patch does not include documentation for the data-race detection facility. The basic design has been explained in various emails, and a separate documentation patch will be submitted later. This work is based on an earlier formulation of data races for the LKMM by Andrea Parri. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
85 lines
3.1 KiB
Plaintext
85 lines
3.1 KiB
Plaintext
// 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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'barrier (*barrier*) ||
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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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(* Compute marked and plain memory accesses *)
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let Marked = (~M) | IW | Once | Release | Acquire | domain(rmw) | range(rmw) |
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LKR | LKW | UL | LF | RL | RU
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let Plain = M \ Marked
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