This is a note to let you know that I've just added the patch titled
perf: Fix event group context move
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-fix-event-group-context-move.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 0231bb5336758426b44ccd798ccd3c5419c95d58 Mon Sep 17 00:00:00 2001
From: Jiri Olsa <[email protected]>
Date: Fri, 1 Feb 2013 11:23:45 +0100
Subject: perf: Fix event group context move
From: Jiri Olsa <[email protected]>
commit 0231bb5336758426b44ccd798ccd3c5419c95d58 upstream.
When we have group with mixed events (hw/sw) we want to end up
with group leader being in hw context. So if group leader is
initialy sw event, we move all the events under hw context.
The move is done for each event by removing it from its context
and adding it back into proper one. As a part of the removal the
event is automatically disabled, which is not what we want at
this stage of creating groups.
The fix is to initialize event state after removal from sw
context.
This fix resulted from the following discussion:
http://thread.gmane.org/gmane.linux.kernel.perf.user/1144
Reported-by: Andreas Hollmann <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Corey Ashford <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Vince Weaver <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Li Zefan <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/events/core.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -911,6 +911,15 @@ list_add_event(struct perf_event *event,
}
/*
+ * Initialize event state based on the perf_event_attr::disabled.
+ */
+static inline void perf_event__state_init(struct perf_event *event)
+{
+ event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
+ PERF_EVENT_STATE_INACTIVE;
+}
+
+/*
* Called at perf_event creation and when events are attached/detached from a
* group.
*/
@@ -6058,8 +6067,7 @@ perf_event_alloc(struct perf_event_attr
event->overflow_handler = overflow_handler;
event->overflow_handler_context = context;
- if (attr->disabled)
- event->state = PERF_EVENT_STATE_OFF;
+ perf_event__state_init(event);
pmu = NULL;
@@ -6481,9 +6489,17 @@ SYSCALL_DEFINE5(perf_event_open,
mutex_lock(&gctx->mutex);
perf_remove_from_context(group_leader);
+
+ /*
+ * Removing from the context ends up with disabled
+ * event. What we want here is event in the initial
+ * startup state, ready to be add into new context.
+ */
+ perf_event__state_init(group_leader);
list_for_each_entry(sibling, &group_leader->sibling_list,
group_entry) {
perf_remove_from_context(sibling);
+ perf_event__state_init(sibling);
put_ctx(gctx);
}
mutex_unlock(&gctx->mutex);
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/perf-fix-event-group-context-move.patch
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