diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2019-12-23 06:32:54 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-02-21 03:01:11 +0300 |
| commit | 7ff8b4502bc0f576450d4ecbda97fa30e8002ed1 (patch) | |
| tree | 9f86c585fad2a69e0085e77448dbecbdc896e6be /kernel/rcu/srcutree.c | |
| parent | bb6d3fb354c5ee8d6bde2d576eb7220ea09862b9 (diff) | |
srcu: Fix __call_srcu()/process_srcu() datarace
The srcu_node structure's ->srcu_gp_seq_needed_exp field is accessed
locklessly, so updates must use WRITE_ONCE(). This commit therefore
adds the needed WRITE_ONCE() invocations.
This data race was reported by KCSAN. Not appropriate for backporting
due to failure being unlikely.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/srcutree.c')
| -rw-r--r-- | kernel/rcu/srcutree.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 657e6a7d1c03..b1edac93e403 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -550,7 +550,7 @@ static void srcu_gp_end(struct srcu_struct *ssp) snp->srcu_have_cbs[idx] = gpseq; rcu_seq_set_state(&snp->srcu_have_cbs[idx], 1); if (ULONG_CMP_LT(snp->srcu_gp_seq_needed_exp, gpseq)) - snp->srcu_gp_seq_needed_exp = gpseq; + WRITE_ONCE(snp->srcu_gp_seq_needed_exp, gpseq); mask = snp->srcu_data_have_cbs[idx]; snp->srcu_data_have_cbs[idx] = 0; spin_unlock_irq_rcu_node(snp); @@ -660,7 +660,7 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp, if (snp == sdp->mynode) snp->srcu_data_have_cbs[idx] |= sdp->grpmask; if (!do_norm && ULONG_CMP_LT(snp->srcu_gp_seq_needed_exp, s)) - snp->srcu_gp_seq_needed_exp = s; + WRITE_ONCE(snp->srcu_gp_seq_needed_exp, s); spin_unlock_irqrestore_rcu_node(snp, flags); } |