2015-02-23 17:38:31

by Fabian Frédérick

Subject: [PATCH 1/1 net-next] irda: replace current->state by set_current_state()

Use helper functions to access current->state.
Direct assignments are prone to races and therefore buggy.

current->state = TASK_RUNNING can be replaced by __set_current_state()

Thanks to Peter Zijlstra for the exact definition of the problem.

Suggested-By: Peter Zijlstra <[email protected]>
Signed-off-by: Fabian Frederick <[email protected]>
---
net/irda/ircomm/ircomm_tty.c | 2 +-
net/irda/irnet/irnet_ppp.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index 40695b9..9940a41 100644
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -811,7 +811,7 @@ static void ircomm_tty_wait_until_sent(struct tty_struct *tty, int timeout)
break;
}
spin_unlock_irqrestore(&self->spinlock, flags);
- current->state = TASK_RUNNING;
+ __set_current_state(TASK_RUNNING);
}

/*
diff --git a/net/irda/irnet/irnet_ppp.c b/net/irda/irnet/irnet_ppp.c
index 3c83a1e..1215693 100644
--- a/net/irda/irnet/irnet_ppp.c
+++ b/net/irda/irnet/irnet_ppp.c
@@ -305,7 +305,7 @@ irnet_ctrl_read(irnet_socket * ap,

/* Put ourselves on the wait queue to be woken up */
add_wait_queue(&irnet_events.rwait, &wait);
- current->state = TASK_INTERRUPTIBLE;
+ set_current_state(TASK_INTERRUPTIBLE);
for(;;)
{
/* If there is unread events */
@@ -321,7 +321,7 @@ irnet_ctrl_read(irnet_socket * ap,
/* Yield and wait to be woken up */
schedule();
}
- current->state = TASK_RUNNING;
+ __set_current_state(TASK_RUNNING);
remove_wait_queue(&irnet_events.rwait, &wait);

/* Did we got it ? */
--
2.1.0

2015-02-23 22:21:29

by David Miller

Subject: Re: [PATCH 1/1 net-next] irda: replace current->state by set_current_state()

From: Fabian Frederick <[email protected]>
Date: Mon, 23 Feb 2015 18:38:24 +0100

> Use helper functions to access current->state.
> Direct assignments are prone to races and therefore buggy.
>
> current->state = TASK_RUNNING can be replaced by __set_current_state()
>
> Thanks to Peter Zijlstra for the exact definition of the problem.
>
> Suggested-By: Peter Zijlstra <[email protected]>
> Signed-off-by: Fabian Frederick <[email protected]>

Applied.