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| author |   Paul E. McKenney <paulmck@kernel.org> | 2020-01-07 15:48:39 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-02-20 15:58:22 -0800 |
| commit | a5b8950180f8e5acb802d1672e0b4d0ceee6126e (patch) | |
| tree | fa0f8d7e3bd76c2db2df2c59d818c6b2f8def89c /kernel/rcu/tree_stall.h | |
| parent | rcu: Fix typos in file-header comments (diff) | |
| download | linux-dev-a5b8950180f8e5acb802d1672e0b4d0ceee6126e.tar.xz linux-dev-a5b8950180f8e5acb802d1672e0b4d0ceee6126e.zip | |
rcu: Add READ_ONCE() to rcu_data ->gpwrap
The rcu_data structure's ->gpwrap field is read locklessly, and so
this commit adds the required READ_ONCE() to a pair of laods in order
to avoid destructive compiler optimizations.
This data race was reported by KCSAN.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/tree_stall.h')
| -rw-r--r-- | kernel/rcu/tree_stall.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 43dc688c3785..bca637b274fb 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -602,7 +602,7 @@ void show_rcu_gp_kthreads(void) continue; for_each_leaf_node_possible_cpu(rnp, cpu) { rdp = per_cpu_ptr(&rcu_data, cpu); - if (rdp->gpwrap || + if (READ_ONCE(rdp->gpwrap) || ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq), READ_ONCE(rdp->gp_seq_needed))) continue; |