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Diffstat (limited to 'kernel/events/core.c')
-rw-r--r--kernel/events/core.c80
1 files changed, 55 insertions, 25 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8e1290340aaf..521d64b355ef 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1899,28 +1899,34 @@ static inline void perf_event__state_init(struct perf_event *event)
PERF_EVENT_STATE_INACTIVE;
}
-static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
+static int __perf_event_read_size(u64 read_format, int nr_siblings)
{
int entry = sizeof(u64); /* value */
int size = 0;
int nr = 1;
- if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
size += sizeof(u64);
- if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
size += sizeof(u64);
- if (event->attr.read_format & PERF_FORMAT_ID)
+ if (read_format & PERF_FORMAT_ID)
+ entry += sizeof(u64);
+
+ if (read_format & PERF_FORMAT_LOST)
entry += sizeof(u64);
- if (event->attr.read_format & PERF_FORMAT_GROUP) {
+ if (read_format & PERF_FORMAT_GROUP) {
nr += nr_siblings;
size += sizeof(u64);
}
- size += entry * nr;
- event->read_size = size;
+ /*
+ * Since perf_event_validate_size() limits this to 16k and inhibits
+ * adding more siblings, this will never overflow.
+ */
+ return size + nr * entry;
}
static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
@@ -1970,8 +1976,9 @@ static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
*/
static void perf_event__header_size(struct perf_event *event)
{
- __perf_event_read_size(event,
- event->group_leader->nr_siblings);
+ event->read_size =
+ __perf_event_read_size(event->attr.read_format,
+ event->group_leader->nr_siblings);
__perf_event_header_size(event, event->attr.sample_type);
}
@@ -2002,24 +2009,35 @@ static void perf_event__id_header_size(struct perf_event *event)
event->id_header_size = size;
}
+/*
+ * Check that adding an event to the group does not result in anybody
+ * overflowing the 64k event limit imposed by the output buffer.
+ *
+ * Specifically, check that the read_size for the event does not exceed 16k,
+ * read_size being the one term that grows with groups size. Since read_size
+ * depends on per-event read_format, also (re)check the existing events.
+ *
+ * This leaves 48k for the constant size fields and things like callchains,
+ * branch stacks and register sets.
+ */
static bool perf_event_validate_size(struct perf_event *event)
{
- /*
- * The values computed here will be over-written when we actually
- * attach the event.
- */
- __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
- __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
- perf_event__id_header_size(event);
+ struct perf_event *sibling, *group_leader = event->group_leader;
- /*
- * Sum the lot; should not exceed the 64k limit we have on records.
- * Conservative limit to allow for callchains and other variable fields.
- */
- if (event->read_size + event->header_size +
- event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
+ if (__perf_event_read_size(event->attr.read_format,
+ group_leader->nr_siblings + 1) > 16*1024)
+ return false;
+
+ if (__perf_event_read_size(group_leader->attr.read_format,
+ group_leader->nr_siblings + 1) > 16*1024)
return false;
+ for_each_sibling_event(sibling, group_leader) {
+ if (__perf_event_read_size(sibling->attr.read_format,
+ group_leader->nr_siblings + 1) > 16*1024)
+ return false;
+ }
+
return true;
}
@@ -5431,11 +5449,15 @@ static int __perf_read_group_add(struct perf_event *leader,
values[n++] += perf_event_count(leader);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
+ if (read_format & PERF_FORMAT_LOST)
+ values[n++] = atomic64_read(&leader->lost_samples);
for_each_sibling_event(sub, leader) {
values[n++] += perf_event_count(sub);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
+ if (read_format & PERF_FORMAT_LOST)
+ values[n++] = atomic64_read(&sub->lost_samples);
}
unlock:
@@ -5489,7 +5511,7 @@ static int perf_read_one(struct perf_event *event,
u64 read_format, char __user *buf)
{
u64 enabled, running;
- u64 values[4];
+ u64 values[5];
int n = 0;
values[n++] = __perf_event_read_value(event, &enabled, &running);
@@ -5499,6 +5521,8 @@ static int perf_read_one(struct perf_event *event,
values[n++] = running;
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(event);
+ if (read_format & PERF_FORMAT_LOST)
+ values[n++] = atomic64_read(&event->lost_samples);
if (copy_to_user(buf, values, n * sizeof(u64)))
return -EFAULT;
@@ -7059,7 +7083,7 @@ static void perf_output_read_one(struct perf_output_handle *handle,
u64 enabled, u64 running)
{
u64 read_format = event->attr.read_format;
- u64 values[4];
+ u64 values[5];
int n = 0;
values[n++] = perf_event_count(event);
@@ -7073,6 +7097,8 @@ static void perf_output_read_one(struct perf_output_handle *handle,
}
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(event);
+ if (read_format & PERF_FORMAT_LOST)
+ values[n++] = atomic64_read(&event->lost_samples);
__output_copy(handle, values, n * sizeof(u64));
}
@@ -7083,7 +7109,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
{
struct perf_event *leader = event->group_leader, *sub;
u64 read_format = event->attr.read_format;
- u64 values[5];
+ u64 values[6];
int n = 0;
values[n++] = 1 + leader->nr_siblings;
@@ -7101,6 +7127,8 @@ static void perf_output_read_group(struct perf_output_handle *handle,
values[n++] = perf_event_count(leader);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
+ if (read_format & PERF_FORMAT_LOST)
+ values[n++] = atomic64_read(&leader->lost_samples);
__output_copy(handle, values, n * sizeof(u64));
@@ -7114,6 +7142,8 @@ static void perf_output_read_group(struct perf_output_handle *handle,
values[n++] = perf_event_count(sub);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
+ if (read_format & PERF_FORMAT_LOST)
+ values[n++] = atomic64_read(&sub->lost_samples);
__output_copy(handle, values, n * sizeof(u64));
}
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-30 06:24:37 +0000