Commit-ID: 682076ae1de0aba9c2da509f7b19dc03e30a6e1f
Gitweb: http://git.kernel.org/tip/682076ae1de0aba9c2da509f7b19dc03e30a6e1f
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Sat, 23 May 2009 18:28:57 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sat, 23 May 2009 19:37:46 +0200
perf_counter: Sanitize context locking
Ensure we're consistent with the context locks.
context->mutex
context->lock
list_{add,del}_counter();
so that either lock is sufficient to stabilize the context.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: John Kacur <jkacur@xxxxxxxxxx>
LKML-Reference: <20090523163012.618790733@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/perf_counter.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 679c3b5..d162d2f 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -597,6 +597,8 @@ static void add_counter_to_ctx(struct perf_counter *counter,
/*
* Cross CPU call to install and enable a performance counter
+ *
+ * Must be called with ctx->mutex held
*/
static void __perf_install_in_context(void *info)
{
@@ -1496,13 +1498,13 @@ static void perf_counter_for_each_sibling(struct perf_counter *counter,
struct perf_counter_context *ctx = counter->ctx;
struct perf_counter *sibling;
- spin_lock_irq(&ctx->lock);
+ mutex_lock(&ctx->mutex);
counter = counter->group_leader;
func(counter);
list_for_each_entry(sibling, &counter->sibling_list, list_entry)
func(sibling);
- spin_unlock_irq(&ctx->lock);
+ mutex_unlock(&ctx->mutex);
}
static void perf_counter_for_each_child(struct perf_counter *counter,
@@ -3414,7 +3416,10 @@ __perf_counter_exit_task(struct task_struct *child,
struct perf_counter *parent_counter;
update_counter_times(child_counter);
+
+ spin_lock_irq(&child_ctx->lock);
list_del_counter(child_counter, child_ctx);
+ spin_unlock_irq(&child_ctx->lock);
parent_counter = child_counter->parent;
/*
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|