| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20210721202127.2129660-14-paulmck@kernel.org>
Date: Wed, 21 Jul 2021 13:21:22 -0700
From: "Paul E. McKenney" <paulmck@...nel.org>
To: rcu@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, kernel-team@...com, mingo@...nel.org,
jiangshanlai@...il.com, akpm@...ux-foundation.org,
mathieu.desnoyers@...icios.com, josh@...htriplett.org,
tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
dhowells@...hat.com, edumazet@...gle.com, fweisbec@...il.com,
oleg@...hat.com, joel@...lfernandes.org,
"Paul E. McKenney" <paulmck@...nel.org>
Subject: [PATCH rcu 14/18] rcu: Mark accesses in tree_stall.h
This commit marks the accesses in tree_stall.h so as to both avoid
undesirable compiler optimizations and to keep KCSAN focused on the
accesses of the core algorithm.
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
kernel/rcu/tree_stall.h | 63 +++++++++++++++++++++--------------------
1 file changed, 33 insertions(+), 30 deletions(-)
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index 6dd6c9aa3f757..a8d0fcf0826f4 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -465,9 +465,10 @@ static void rcu_check_gp_kthread_starvation(void)
pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#x ->cpu=%d\n",
rcu_state.name, j,
(long)rcu_seq_current(&rcu_state.gp_seq),
- data_race(rcu_state.gp_flags),
- gp_state_getname(rcu_state.gp_state), rcu_state.gp_state,
- gpk ? gpk->__state : ~0, cpu);
+ data_race(READ_ONCE(rcu_state.gp_flags)),
+ gp_state_getname(rcu_state.gp_state),
+ data_race(READ_ONCE(rcu_state.gp_state)),
+ gpk ? data_race(READ_ONCE(gpk->__state)) : ~0, cpu);
if (gpk) {
pr_err("\tUnless %s kthread gets sufficient CPU time, OOM is now expected behavior.\n", rcu_state.name);
pr_err("RCU grace-period kthread stack dump:\n");
@@ -510,7 +511,7 @@ static void rcu_check_gp_kthread_expired_fqs_timer(void)
(long)rcu_seq_current(&rcu_state.gp_seq),
data_race(rcu_state.gp_flags),
gp_state_getname(RCU_GP_WAIT_FQS), RCU_GP_WAIT_FQS,
- gpk->__state);
+ data_race(READ_ONCE(gpk->__state)));
pr_err("\tPossible timer handling issue on cpu=%d timer-softirq=%u\n",
cpu, kstat_softirqs_cpu(TIMER_SOFTIRQ, cpu));
}
@@ -569,11 +570,11 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
pr_err("INFO: Stall ended before state dump start\n");
} else {
j = jiffies;
- gpa = data_race(rcu_state.gp_activity);
+ gpa = data_race(READ_ONCE(rcu_state.gp_activity));
pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx\n",
rcu_state.name, j - gpa, j, gpa,
- data_race(jiffies_till_next_fqs),
- rcu_get_root()->qsmask);
+ data_race(READ_ONCE(jiffies_till_next_fqs)),
+ data_race(READ_ONCE(rcu_get_root()->qsmask)));
}
}
/* Rewrite if needed in case of slow consoles. */
@@ -815,32 +816,34 @@ void show_rcu_gp_kthreads(void)
struct task_struct *t = READ_ONCE(rcu_state.gp_kthread);
j = jiffies;
- ja = j - data_race(rcu_state.gp_activity);
- jr = j - data_race(rcu_state.gp_req_activity);
- js = j - data_race(rcu_state.gp_start);
- jw = j - data_race(rcu_state.gp_wake_time);
+ ja = j - data_race(READ_ONCE(rcu_state.gp_activity));
+ jr = j - data_race(READ_ONCE(rcu_state.gp_req_activity));
+ js = j - data_race(READ_ONCE(rcu_state.gp_start));
+ jw = j - data_race(READ_ONCE(rcu_state.gp_wake_time));
pr_info("%s: wait state: %s(%d) ->state: %#x ->rt_priority %u delta ->gp_start %lu ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_max %lu ->gp_flags %#x\n",
rcu_state.name, gp_state_getname(rcu_state.gp_state),
- rcu_state.gp_state, t ? t->__state : 0x1ffff, t ? t->rt_priority : 0xffU,
- js, ja, jr, jw, (long)data_race(rcu_state.gp_wake_seq),
- (long)data_race(rcu_state.gp_seq),
- (long)data_race(rcu_get_root()->gp_seq_needed),
- data_race(rcu_state.gp_max),
- data_race(rcu_state.gp_flags));
+ data_race(READ_ONCE(rcu_state.gp_state)),
+ t ? data_race(READ_ONCE(t->__state)) : 0x1ffff, t ? t->rt_priority : 0xffU,
+ js, ja, jr, jw, (long)data_race(READ_ONCE(rcu_state.gp_wake_seq)),
+ (long)data_race(READ_ONCE(rcu_state.gp_seq)),
+ (long)data_race(READ_ONCE(rcu_get_root()->gp_seq_needed)),
+ data_race(READ_ONCE(rcu_state.gp_max)),
+ data_race(READ_ONCE(rcu_state.gp_flags)));
rcu_for_each_node_breadth_first(rnp) {
if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq), READ_ONCE(rnp->gp_seq_needed)) &&
- !data_race(rnp->qsmask) && !data_race(rnp->boost_tasks) &&
- !data_race(rnp->exp_tasks) && !data_race(rnp->gp_tasks))
+ !data_race(READ_ONCE(rnp->qsmask)) && !data_race(READ_ONCE(rnp->boost_tasks)) &&
+ !data_race(READ_ONCE(rnp->exp_tasks)) && !data_race(READ_ONCE(rnp->gp_tasks)))
continue;
pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld ->qsmask %#lx %c%c%c%c ->n_boosts %ld\n",
rnp->grplo, rnp->grphi,
- (long)data_race(rnp->gp_seq), (long)data_race(rnp->gp_seq_needed),
- data_race(rnp->qsmask),
- ".b"[!!data_race(rnp->boost_kthread_task)],
- ".B"[!!data_race(rnp->boost_tasks)],
- ".E"[!!data_race(rnp->exp_tasks)],
- ".G"[!!data_race(rnp->gp_tasks)],
- data_race(rnp->n_boosts));
+ (long)data_race(READ_ONCE(rnp->gp_seq)),
+ (long)data_race(READ_ONCE(rnp->gp_seq_needed)),
+ data_race(READ_ONCE(rnp->qsmask)),
+ ".b"[!!data_race(READ_ONCE(rnp->boost_kthread_task))],
+ ".B"[!!data_race(READ_ONCE(rnp->boost_tasks))],
+ ".E"[!!data_race(READ_ONCE(rnp->exp_tasks))],
+ ".G"[!!data_race(READ_ONCE(rnp->gp_tasks))],
+ data_race(READ_ONCE(rnp->n_boosts)));
if (!rcu_is_leaf_node(rnp))
continue;
for_each_leaf_node_possible_cpu(rnp, cpu) {
@@ -850,12 +853,12 @@ void show_rcu_gp_kthreads(void)
READ_ONCE(rdp->gp_seq_needed)))
continue;
pr_info("\tcpu %d ->gp_seq_needed %ld\n",
- cpu, (long)data_race(rdp->gp_seq_needed));
+ cpu, (long)data_race(READ_ONCE(rdp->gp_seq_needed)));
}
}
for_each_possible_cpu(cpu) {
rdp = per_cpu_ptr(&rcu_data, cpu);
- cbs += data_race(rdp->n_cbs_invoked);
+ cbs += data_race(READ_ONCE(rdp->n_cbs_invoked));
if (rcu_segcblist_is_offloaded(&rdp->cblist))
show_rcu_nocb_state(rdp);
}
@@ -937,11 +940,11 @@ void rcu_fwd_progress_check(unsigned long j)
if (rcu_gp_in_progress()) {
pr_info("%s: GP age %lu jiffies\n",
- __func__, jiffies - rcu_state.gp_start);
+ __func__, jiffies - data_race(READ_ONCE(rcu_state.gp_start)));
show_rcu_gp_kthreads();
} else {
pr_info("%s: Last GP end %lu jiffies ago\n",
- __func__, jiffies - rcu_state.gp_end);
+ __func__, jiffies - data_race(READ_ONCE(rcu_state.gp_end)));
preempt_disable();
rdp = this_cpu_ptr(&rcu_data);
rcu_check_gp_start_stall(rdp->mynode, rdp, j);
--
2.31.1.189.g2e36527f23
Powered by blists - more mailing lists