From: Mark Rutland <mark.rutland@arm.com>
To: linux-kernel@vger.kernel.org
Cc: benh@kernel.crashing.org, boqun.feng@gmail.com, bp@alien8.de,
catalin.marinas@arm.com, dvyukov@google.com, elver@google.com,
ink@jurassic.park.msu.ru, jonas@southpole.se,
juri.lelli@redhat.com, linux@armlinux.org.uk, luto@kernel.org,
mark.rutland@arm.com, mattst88@gmail.com, mingo@redhat.com,
monstr@monstr.eu, mpe@ellerman.id.au, paulmck@kernel.org,
paulus@samba.org, peterz@infradead.org, rth@twiddle.net,
shorne@gmail.com, stefan.kristiansson@saunalahti.fi,
tglx@linutronix.de, vincent.guittot@linaro.org, will@kernel.org
Subject: [PATCH v3 03/10] sched: snapshot thread flags
Date: Tue, 13 Jul 2021 12:38:35 +0100 [thread overview]
Message-ID: <20210713113842.2106-4-mark.rutland@arm.com> (raw)
In-Reply-To: <20210713113842.2106-1-mark.rutland@arm.com>
Some thread flags can be set remotely, and so even when IRQs are
disabled, the flags can change under our feet. Generally this is
unlikely to cause a problem in practice, but it is somewhat unsound, and
KCSAN will legitimately warn that there is a data race.
To avoid such issues, a snapshot of the flags has to be taken prior to
using them. Some places already use READ_ONCE() for that, others do not.
Convert them all to the new flag accessor helpers.
The READ_ONCE(ti->flags) .. cmpxchg(ti->flags) loop in
set_nr_if_polling() is left as-is for clarity.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d9ff40f4661..bbce979c513d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8157,7 +8157,7 @@ void sched_show_task(struct task_struct *p)
rcu_read_unlock();
pr_cont(" stack:%5lu pid:%5d ppid:%6d flags:0x%08lx\n",
free, task_pid_nr(p), ppid,
- (unsigned long)task_thread_info(p)->flags);
+ read_task_thread_flags(p));
print_worker_info(KERN_INFO, p);
print_stop_info(KERN_INFO, p);
--
2.11.0
next prev parent reply other threads:[~2021-07-13 11:39 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-13 11:38 [PATCH v3 00/10] thread_info: use helpers to snapshot thread flags Mark Rutland
2021-07-13 11:38 ` [PATCH v3 01/10] thread_info: add " Mark Rutland
2021-07-13 11:38 ` [PATCH v3 02/10] entry: " Mark Rutland
2021-07-13 11:38 ` Mark Rutland [this message]
2021-07-13 11:38 ` [PATCH v3 04/10] alpha: " Mark Rutland
2021-07-13 11:38 ` [PATCH v3 05/10] arm: " Mark Rutland
2021-07-13 11:38 ` [PATCH v3 06/10] arm64: " Mark Rutland
2021-07-13 11:38 ` [PATCH v3 07/10] microblaze: " Mark Rutland
2021-07-13 11:38 ` [PATCH v3 08/10] openrisc: " Mark Rutland
2021-07-13 11:38 ` [PATCH v3 09/10] powerpc: " Mark Rutland
2021-07-13 11:38 ` [PATCH v3 10/10] x86: " Mark Rutland
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