From 682076ae1de0aba9c2da509f7b19dc03e30a6e1f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 23 May 2009 18:28:57 +0200 Subject: [PATCH] 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 Cc: Paul Mackerras Cc: Corey Ashford Cc: Arnaldo Carvalho de Melo Cc: John Kacur LKML-Reference: <20090523163012.618790733@chello.nl> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 679c3b5bb7d4..d162d2f0b270 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; /* -- 2.39.5