49 lines
1.8 KiB
Diff
49 lines
1.8 KiB
Diff
Subject: sched/rt: Fix wait_task_interactive() to test rt_spin_lock state
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From: Steven Rostedt <rostedt@goodmis.org>
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Date: Thu, 01 Mar 2012 13:55:33 -0500
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The wait_task_interactive() will have a task sleep waiting for another
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task to have a certain state. But it ignores the rt_spin_locks state
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and can return with an incorrect result if the task it is waiting
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for is blocked on a rt_spin_lock() and is waking up.
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The rt_spin_locks save the tasks state in the saved_state field
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and the wait_task_interactive() must also test that state.
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Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Cc: Carsten Emde <C.Emde@osadl.org>
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Cc: John Kacur <jkacur@redhat.com>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Clark Williams <clark.williams@gmail.com>
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Cc: stable-rt@vger.kernel.org
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Link: http://lkml.kernel.org/r/20120301190345.979435764@goodmis.org
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/sched/core.c | 6 ++++--
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1 file changed, 4 insertions(+), 2 deletions(-)
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Index: linux-3.4/kernel/sched/core.c
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===================================================================
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--- linux-3.4.orig/kernel/sched/core.c
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+++ linux-3.4/kernel/sched/core.c
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@@ -1174,7 +1174,8 @@ unsigned long wait_task_inactive(struct
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* is actually now running somewhere else!
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*/
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while (task_running(rq, p)) {
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- if (match_state && unlikely(p->state != match_state))
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+ if (match_state && unlikely(p->state != match_state)
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+ && unlikely(p->saved_state != match_state))
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return 0;
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cpu_relax();
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}
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@@ -1189,7 +1190,8 @@ unsigned long wait_task_inactive(struct
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running = task_running(rq, p);
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on_rq = p->on_rq;
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ncsw = 0;
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- if (!match_state || p->state == match_state)
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+ if (!match_state || p->state == match_state
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+ || p->saved_state == match_state)
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ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
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task_rq_unlock(rq, p, &flags);
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