Messages in this thread Patch in this message | | | From | Joel Fernandes <> | Subject | [PATCH v3 4/4] rcu: Unlock non-start node only after accessing its gp_seq_needed | Date | Sun, 20 May 2018 21:42:20 -0700 |
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We acquire gp_seq_needed locklessly. To be safe, lets do the unlocking after the access.
Signed-off-by: Joel Fernandes <joel@joelfernandes.org> --- kernel/rcu/tree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 879c67a31116..efbd21b2a1a6 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1603,13 +1603,13 @@ static bool rcu_start_this_gp(struct rcu_node *rnp_start, struct rcu_data *rdp, trace_rcu_grace_period(rsp->name, READ_ONCE(rsp->gp_seq), TPS("newreq")); ret = true; /* Caller must wake GP kthread. */ unlock_out: - if (rnp != rnp_start) - raw_spin_unlock_rcu_node(rnp); /* Push furthest requested GP to leaf node and rcu_data structure. */ if (ULONG_CMP_GE(rnp->gp_seq_needed, gp_seq_req)) { rnp_start->gp_seq_needed = gp_seq_req; rdp->gp_seq_needed = gp_seq_req; } + if (rnp != rnp_start) + raw_spin_unlock_rcu_node(rnp); return ret; } -- 2.17.0.441.gb46fe60e1d-goog
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