From: madhuparnabhowmik10@gmail.com
To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, ebiederm@xmission.com,
christian.brauner@ubuntu.com, oleg@redhat.com,
paulmck@kernel.org
Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
joel@joelfernandes.org,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu
Date: Thu, 23 Jan 2020 20:23:05 +0530 [thread overview]
Message-ID: <20200123145305.10652-1-madhuparnabhowmik10@gmail.com> (raw)
From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
This patch fixes the following sparse errors by annotating the
sighand_struct with __rcu
kernel/fork.c:1511:9: error: incompatible types in comparison expression
kernel/exit.c:100:19: error: incompatible types in comparison expression
kernel/signal.c:1370:27: error: incompatible types in comparison expression
This fix introduces the following sparse error in signal.c due to
checking the sighand pointer without rcu primitives:
kernel/signal.c:1386:21: error: incompatible types in comparison expression
This new sparse error is also addressed in this patch.
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
---
include/linux/sched.h | 2 +-
kernel/signal.c | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b511e178a89f..7a351360ad54 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -918,7 +918,7 @@ struct task_struct {
/* Signal handlers: */
struct signal_struct *signal;
- struct sighand_struct *sighand;
+ struct sighand_struct __rcu *sighand;
sigset_t blocked;
sigset_t real_blocked;
/* Restored if set_restore_sigmask() was used: */
diff --git a/kernel/signal.c b/kernel/signal.c
index bcd46f547db3..1272def37462 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1383,7 +1383,8 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
* must see ->sighand == NULL.
*/
spin_lock_irqsave(&sighand->siglock, *flags);
- if (likely(sighand == tsk->sighand))
+ if (likely(sighand == rcu_dereference_protected(tsk->sighand,
+ lockdep_is_held(&sighand->siglock))))
break;
spin_unlock_irqrestore(&sighand->siglock, *flags);
}
--
2.17.1
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next reply other threads:[~2020-01-23 14:53 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 14:53 madhuparnabhowmik10 [this message]
2020-01-23 16:41 ` [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu Paul E. McKenney
2020-01-24 4:28 ` Madhuparna Bhowmik
-- strict thread matches above, loose matches on Subject: below --
2020-01-24 4:59 madhuparnabhowmik10
2020-01-25 21:41 ` Christian Brauner
2020-01-26 1:23 ` Paul E. McKenney
2020-01-27 9:29 ` Oleg Nesterov
2020-01-27 12:23 ` Christian Brauner
2020-01-27 17:14 ` Madhuparna Bhowmik
2020-01-22 18:11 madhuparnabhowmik10
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