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-rw-r--r--kernel/perf_event.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 3472bb1a070c..8e81a9860a0d 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -145,7 +145,8 @@ static struct srcu_struct pmus_srcu;
*/
int sysctl_perf_event_paranoid __read_mostly = 1;
-int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
+/* Minimum for 512 kiB + 1 user control page */
+int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
/*
* max perf event sample rate
@@ -363,6 +364,7 @@ void perf_cgroup_switch(struct task_struct *task, int mode)
}
if (mode & PERF_CGROUP_SWIN) {
+ WARN_ON_ONCE(cpuctx->cgrp);
/* set cgrp before ctxsw in to
* allow event_filter_match() to not
* have to pass task around
@@ -941,6 +943,7 @@ static void perf_group_attach(struct perf_event *event)
static void
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
{
+ struct perf_cpu_context *cpuctx;
/*
* We can have double detach due to exit/hot-unplug + close.
*/
@@ -949,8 +952,17 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
event->attach_state &= ~PERF_ATTACH_CONTEXT;
- if (is_cgroup_event(event))
+ if (is_cgroup_event(event)) {
ctx->nr_cgroups--;
+ cpuctx = __get_cpu_context(ctx);
+ /*
+ * if there are no more cgroup events
+ * then cler cgrp to avoid stale pointer
+ * in update_cgrp_time_from_cpuctx()
+ */
+ if (!ctx->nr_cgroups)
+ cpuctx->cgrp = NULL;
+ }
ctx->nr_events--;
if (event->attr.inherit_stat)
@@ -2412,6 +2424,14 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx)
if (!ctx || !ctx->nr_events)
goto out;
+ /*
+ * We must ctxsw out cgroup events to avoid conflict
+ * when invoking perf_task_event_sched_in() later on
+ * in this function. Otherwise we end up trying to
+ * ctxswin cgroup events which are already scheduled
+ * in.
+ */
+ perf_cgroup_sched_out(current);
task_ctx_sched_out(ctx, EVENT_ALL);
raw_spin_lock(&ctx->lock);
@@ -2436,6 +2456,9 @@ static void perf_event_enable_on_exec(struct perf_event_context *ctx)
raw_spin_unlock(&ctx->lock);
+ /*
+ * Also calls ctxswin for cgroup events, if any:
+ */
perf_event_context_sched_in(ctx, ctx->task);
out:
local_irq_restore(flags);
@@ -6520,6 +6543,11 @@ SYSCALL_DEFINE5(perf_event_open,
goto err_alloc;
}
+ if (task) {
+ put_task_struct(task);
+ task = NULL;
+ }
+
/*
* Look up the group leader (we will attach this event to it):
*/