From 652884fe0c7bd57f534c5fe68d6def0dc8c4b7ed Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 23 Jan 2015 11:20:10 +0100 Subject: [PATCH] perf: Add a bit of paranoia Add a few WARN()s to catch things that should never happen. Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20150123125834.150481799@infradead.org Signed-off-by: Ingo Molnar --- kernel/events/core.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index b4a696c4dc76..b358cb38e4a5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1275,6 +1275,8 @@ static void perf_group_attach(struct perf_event *event) if (group_leader == event) return; + WARN_ON_ONCE(group_leader->ctx != event->ctx); + if (group_leader->group_flags & PERF_GROUP_SOFTWARE && !is_software_event(event)) group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; @@ -1296,6 +1298,10 @@ static void list_del_event(struct perf_event *event, struct perf_event_context *ctx) { struct perf_cpu_context *cpuctx; + + WARN_ON_ONCE(event->ctx != ctx); + lockdep_assert_held(&ctx->lock); + /* * We can have double detach due to exit/hot-unplug + close. */ @@ -1380,6 +1386,8 @@ static void perf_group_detach(struct perf_event *event) /* Inherit group flags from the previous leader */ sibling->group_flags = event->group_flags; + + WARN_ON_ONCE(sibling->ctx != event->ctx); } out: @@ -1442,6 +1450,10 @@ event_sched_out(struct perf_event *event, { u64 tstamp = perf_event_time(event); u64 delta; + + WARN_ON_ONCE(event->ctx != ctx); + lockdep_assert_held(&ctx->lock); + /* * An event which could not be activated because of * filter mismatch still needs to have its timings @@ -7822,14 +7834,19 @@ static void perf_free_event(struct perf_event *event, put_event(parent); + raw_spin_lock_irq(&ctx->lock); perf_group_detach(event); list_del_event(event, ctx); + raw_spin_unlock_irq(&ctx->lock); free_event(event); } /* - * free an unexposed, unused context as created by inheritance by + * Free an unexposed, unused context as created by inheritance by * perf_event_init_task below, used by fork() in case of fail. + * + * Not all locks are strictly required, but take them anyway to be nice and + * help out with the lockdep assertions. */ void perf_event_free_task(struct task_struct *task) { -- 2.20.1