mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 11:49:32 +00:00
rcu: Add READ_ONCE() to rcu_node ->gp_seq
The rcu_node structure's ->gp_seq field is read locklessly, so this commit adds the READ_ONCE() to several loads in order to avoid destructive compiler optimizations. This data race was reported by KCSAN. Not appropriate for backporting because this affects only tracing and warnings. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
parent
b0c18c8773
commit
0937d04573
1 changed files with 5 additions and 4 deletions
|
@ -1126,8 +1126,9 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
|
|||
static void trace_rcu_this_gp(struct rcu_node *rnp, struct rcu_data *rdp,
|
||||
unsigned long gp_seq_req, const char *s)
|
||||
{
|
||||
trace_rcu_future_grace_period(rcu_state.name, rnp->gp_seq, gp_seq_req,
|
||||
rnp->level, rnp->grplo, rnp->grphi, s);
|
||||
trace_rcu_future_grace_period(rcu_state.name, READ_ONCE(rnp->gp_seq),
|
||||
gp_seq_req, rnp->level,
|
||||
rnp->grplo, rnp->grphi, s);
|
||||
}
|
||||
|
||||
/*
|
||||
|
@ -1904,7 +1905,7 @@ static void rcu_report_qs_rnp(unsigned long mask, struct rcu_node *rnp,
|
|||
rnp_c = rnp;
|
||||
rnp = rnp->parent;
|
||||
raw_spin_lock_irqsave_rcu_node(rnp, flags);
|
||||
oldmask = rnp_c->qsmask;
|
||||
oldmask = READ_ONCE(rnp_c->qsmask);
|
||||
}
|
||||
|
||||
/*
|
||||
|
@ -2052,7 +2053,7 @@ int rcutree_dying_cpu(unsigned int cpu)
|
|||
return 0;
|
||||
|
||||
blkd = !!(rnp->qsmask & rdp->grpmask);
|
||||
trace_rcu_grace_period(rcu_state.name, rnp->gp_seq,
|
||||
trace_rcu_grace_period(rcu_state.name, READ_ONCE(rnp->gp_seq),
|
||||
blkd ? TPS("cpuofl") : TPS("cpuofl-bgp"));
|
||||
return 0;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue