rcu.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] sched.h: Annotate sighand_struct with __rcu
@ 2020-01-24  4:59 madhuparnabhowmik10
  2020-01-25 21:41 ` Christian Brauner
  2020-01-27  9:29 ` Oleg Nesterov
  0 siblings, 2 replies; 10+ messages in thread
From: madhuparnabhowmik10 @ 2020-01-24  4:59 UTC (permalink / raw)
  To: mingo, peterz, juri.lelli, vincent.guittot, ebiederm,
	christian.brauner, oleg, paulmck
  Cc: joel, linux-kernel, linux-kernel-mentees, frextrite, rcu,
	Madhuparna Bhowmik

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 fixed in this patch.

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
---
 include/linux/sched.h | 2 +-
 kernel/signal.c       | 2 +-
 2 files changed, 2 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..9ad8dea93dbb 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1383,7 +1383,7 @@ 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_access_pointer(tsk->sighand)))
 			break;
 		spin_unlock_irqrestore(&sighand->siglock, *flags);
 	}
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH] sched.h: Annotate sighand_struct with __rcu
@ 2020-01-23 14:53 madhuparnabhowmik10
  2020-01-23 16:41 ` Paul E. McKenney
  0 siblings, 1 reply; 10+ messages in thread
From: madhuparnabhowmik10 @ 2020-01-23 14:53 UTC (permalink / raw)
  To: mingo, peterz, juri.lelli, vincent.guittot, ebiederm,
	christian.brauner, oleg, paulmck
  Cc: joel, linux-kernel, linux-kernel-mentees, frextrite, rcu,
	Madhuparna Bhowmik

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


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH] sched.h: Annotate sighand_struct with __rcu
@ 2020-01-22 18:11 madhuparnabhowmik10
  0 siblings, 0 replies; 10+ messages in thread
From: madhuparnabhowmik10 @ 2020-01-22 18:11 UTC (permalink / raw)
  To: mingo, peterz
  Cc: linux-kernel, joel, frextrite, rcu, paulmck,
	linux-kernel-mentees, Madhuparna Bhowmik

From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

This patch fixes the following sparse errors:

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

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
---
 include/linux/sched.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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: */
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2020-01-27 17:15 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-24  4:59 [PATCH] sched.h: Annotate sighand_struct with __rcu 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
  -- strict thread matches above, loose matches on Subject: below --
2020-01-23 14:53 madhuparnabhowmik10
2020-01-23 16:41 ` Paul E. McKenney
2020-01-24  4:28   ` Madhuparna Bhowmik
2020-01-22 18:11 madhuparnabhowmik10

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).