* [Linux-kernel-mentees] [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: linux-kernel, rcu, Madhuparna Bhowmik, joel, linux-kernel-mentees
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
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu
2020-01-24 4:59 [Linux-kernel-mentees] [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
1 sibling, 1 reply; 10+ messages in thread
From: Christian Brauner @ 2020-01-25 21:41 UTC (permalink / raw)
To: madhuparnabhowmik10, mingo, peterz, juri.lelli, vincent.guittot,
ebiederm, oleg, paulmck
Cc: linux-kernel, rcu, Madhuparna Bhowmik, joel, linux-kernel-mentees
On January 24, 2020 5:59:08 AM GMT+01:00, madhuparnabhowmik10@gmail.com wrote:
>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);
> }
If Paul is happy with this and nobody wants to take it I'll pick this up.
Thanks!
Christian
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu
2020-01-25 21:41 ` Christian Brauner
@ 2020-01-26 1:23 ` Paul E. McKenney
0 siblings, 0 replies; 10+ messages in thread
From: Paul E. McKenney @ 2020-01-26 1:23 UTC (permalink / raw)
To: Christian Brauner
Cc: juri.lelli, vincent.guittot, peterz, oleg, linux-kernel, rcu,
madhuparnabhowmik10, mingo, ebiederm, joel, linux-kernel-mentees
On Sat, Jan 25, 2020 at 10:41:06PM +0100, Christian Brauner wrote:
> On January 24, 2020 5:59:08 AM GMT+01:00, madhuparnabhowmik10@gmail.com wrote:
> >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>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
> >---
> > 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);
> > }
>
> If Paul is happy with this and nobody wants to take it I'll pick this up.
Works for me!
Thanx, Paul
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu
2020-01-24 4:59 [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu madhuparnabhowmik10
2020-01-25 21:41 ` Christian Brauner
@ 2020-01-27 9:29 ` Oleg Nesterov
2020-01-27 12:23 ` Christian Brauner
2020-01-27 17:14 ` Madhuparna Bhowmik
1 sibling, 2 replies; 10+ messages in thread
From: Oleg Nesterov @ 2020-01-27 9:29 UTC (permalink / raw)
To: madhuparnabhowmik10
Cc: juri.lelli, vincent.guittot, paulmck, peterz, linux-kernel, rcu,
mingo, ebiederm, joel, christian.brauner, linux-kernel-mentees
On 01/24, madhuparnabhowmik10@gmail.com wrote:
>
> --- 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);
> }
ACK,
perhaps you can also cleanup copy_sighand(). rcu_assign_pointer() makes no
sense, we should either move it down or simply use RCU_INIT_POINTER().
Oleg.
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu
2020-01-27 9:29 ` Oleg Nesterov
@ 2020-01-27 12:23 ` Christian Brauner
2020-01-27 17:14 ` Madhuparna Bhowmik
1 sibling, 0 replies; 10+ messages in thread
From: Christian Brauner @ 2020-01-27 12:23 UTC (permalink / raw)
To: Oleg Nesterov
Cc: juri.lelli, vincent.guittot, paulmck, peterz, linux-kernel, rcu,
madhuparnabhowmik10, mingo, ebiederm, joel, linux-kernel-mentees
On Mon, Jan 27, 2020 at 10:29:52AM +0100, Oleg Nesterov wrote:
> On 01/24, madhuparnabhowmik10@gmail.com wrote:
> >
> > --- 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);
> > }
>
> ACK,
Applied.
Thanks Paul and Oleg!
Christian
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu
2020-01-27 9:29 ` Oleg Nesterov
2020-01-27 12:23 ` Christian Brauner
@ 2020-01-27 17:14 ` Madhuparna Bhowmik
1 sibling, 0 replies; 10+ messages in thread
From: Madhuparna Bhowmik @ 2020-01-27 17:14 UTC (permalink / raw)
To: Oleg Nesterov
Cc: juri.lelli, vincent.guittot, paulmck, peterz, linux-kernel, rcu,
madhuparnabhowmik10, mingo, ebiederm, joel, christian.brauner,
linux-kernel-mentees
On Mon, Jan 27, 2020 at 10:29:52AM +0100, Oleg Nesterov wrote:
> On 01/24, madhuparnabhowmik10@gmail.com wrote:
> >
> > --- 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);
> > }
>
> ACK,
>
> perhaps you can also cleanup copy_sighand(). rcu_assign_pointer() makes no
> sense, we should either move it down or simply use RCU_INIT_POINTER().
>
Sure, I will do it and send a patch soon.
Thank you,
Madhuparna
> Oleg.
>
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu
2020-01-23 16:41 ` Paul E. McKenney
@ 2020-01-24 4:28 ` Madhuparna Bhowmik
0 siblings, 0 replies; 10+ messages in thread
From: Madhuparna Bhowmik @ 2020-01-24 4:28 UTC (permalink / raw)
To: Paul E. McKenney
Cc: juri.lelli, vincent.guittot, peterz, oleg, linux-kernel, rcu,
madhuparnabhowmik10, mingo, ebiederm, joel, christian.brauner,
linux-kernel-mentees
On Thu, Jan 23, 2020 at 08:41:08AM -0800, Paul E. McKenney wrote:
> On Thu, Jan 23, 2020 at 08:23:05PM +0530, madhuparnabhowmik10@gmail.com wrote:
> > 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))))
>
> Given that the return value is never dereferenced, you can use
> rcu_access_pointer(), which may be used outside of an RCU read-side
> critical section, and thus does not need the lockdep_is_held(). So this
> change would save a line of code and would be a bit easier on the eyes.
>
Okay got it! I will send the updated patch soon.
Thank you,
Madhuparna
> Thanx, Paul
>
> > break;
> > spin_unlock_irqrestore(&sighand->siglock, *flags);
> > }
> > --
> > 2.17.1
> >
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu
2020-01-23 14:53 madhuparnabhowmik10
@ 2020-01-23 16:41 ` Paul E. McKenney
2020-01-24 4:28 ` Madhuparna Bhowmik
0 siblings, 1 reply; 10+ messages in thread
From: Paul E. McKenney @ 2020-01-23 16:41 UTC (permalink / raw)
To: madhuparnabhowmik10
Cc: juri.lelli, vincent.guittot, peterz, oleg, linux-kernel, rcu,
mingo, ebiederm, joel, christian.brauner, linux-kernel-mentees
On Thu, Jan 23, 2020 at 08:23:05PM +0530, madhuparnabhowmik10@gmail.com wrote:
> 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))))
Given that the return value is never dereferenced, you can use
rcu_access_pointer(), which may be used outside of an RCU read-side
critical section, and thus does not need the lockdep_is_held(). So this
change would save a line of code and would be a bit easier on the eyes.
Thanx, Paul
> break;
> spin_unlock_irqrestore(&sighand->siglock, *flags);
> }
> --
> 2.17.1
>
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Linux-kernel-mentees] [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: linux-kernel, rcu, Madhuparna Bhowmik, joel, linux-kernel-mentees
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
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [Linux-kernel-mentees] [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: paulmck, linux-kernel, rcu, Madhuparna Bhowmik, joel,
linux-kernel-mentees
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
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ 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 [Linux-kernel-mentees] [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).