Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / kernel / events / core.c

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 5d8f4031f8d589cac999d4e09161be159ef754d0..d99fe3fdec8adb18845d42da4d2a75dbcbba6016 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5824,19 +5824,11 @@ void perf_output_sample(struct perf_output_handle *handle,
                perf_output_read(handle, event);
 
        if (sample_type & PERF_SAMPLE_CALLCHAIN) {
-               if (data->callchain) {
-                       int size = 1;
-
-                       if (data->callchain)
-                               size += data->callchain->nr;
-
-                       size *= sizeof(u64);
+               int size = 1;
 
-                       __output_copy(handle, data->callchain, size);
-               } else {
-                       u64 nr = 0;
-                       perf_output_put(handle, nr);
-               }
+               size += data->callchain->nr;
+               size *= sizeof(u64);
+               __output_copy(handle, data->callchain, size);
        }
 
        if (sample_type & PERF_SAMPLE_RAW) {
@@ -5989,6 +5981,26 @@ static u64 perf_virt_to_phys(u64 virt)
        return phys_addr;
 }
 
+static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
+
+static struct perf_callchain_entry *
+perf_callchain(struct perf_event *event, struct pt_regs *regs)
+{
+       bool kernel = !event->attr.exclude_callchain_kernel;
+       bool user   = !event->attr.exclude_callchain_user;
+       /* Disallow cross-task user callchains. */
+       bool crosstask = event->ctx->task && event->ctx->task != current;
+       const u32 max_stack = event->attr.sample_max_stack;
+       struct perf_callchain_entry *callchain;
+
+       if (!kernel && !user)
+               return &__empty_callchain;
+
+       callchain = get_perf_callchain(regs, 0, kernel, user,
+                                      max_stack, crosstask, true);
+       return callchain ?: &__empty_callchain;
+}
+
 void perf_prepare_sample(struct perf_event_header *header,
                         struct perf_sample_data *data,
                         struct perf_event *event,
@@ -6011,9 +6023,7 @@ void perf_prepare_sample(struct perf_event_header *header,
                int size = 1;
 
                data->callchain = perf_callchain(event, regs);
-
-               if (data->callchain)
-                       size += data->callchain->nr;
+               size += data->callchain->nr;
 
                header->size += size * sizeof(u64);
        }
@@ -10740,6 +10750,19 @@ inherit_event(struct perf_event *parent_event,
        if (IS_ERR(child_event))
                return child_event;
 
+
+       if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
+           !child_ctx->task_ctx_data) {
+               struct pmu *pmu = child_event->pmu;
+
+               child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
+                                                  GFP_KERNEL);
+               if (!child_ctx->task_ctx_data) {
+                       free_event(child_event);
+                       return NULL;
+               }
+       }
+
        /*
         * is_orphaned_event() and list_add_tail(&parent_event->child_list)
         * must be under the same lock in order to serialize against
@@ -10750,6 +10773,7 @@ inherit_event(struct perf_event *parent_event,
        if (is_orphaned_event(parent_event) ||
            !atomic_long_inc_not_zero(&parent_event->refcount)) {
                mutex_unlock(&parent_event->child_mutex);
+               /* task_ctx_data is freed with child_ctx */
                free_event(child_event);
                return NULL;
        }