From e03e7ee34fdd1c3ef494949a75cb8c61c7265fa9 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Mon, 25 Jan 2016 20:59:49 -0800 Subject: perf/bpf: Convert perf_event_array to use struct file Robustify refcounting. Signed-off-by: Alexei Starovoitov Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Daniel Borkmann Cc: David Ahern Cc: Jiri Olsa Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: Wang Nan Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160126045947.GA40151@ast-mbp.thefacebook.com Signed-off-by: Ingo Molnar --- kernel/trace/bpf_trace.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'kernel/trace') diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 45dd798bcd37..326a75e884db 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -191,14 +191,17 @@ static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5) struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; struct bpf_array *array = container_of(map, struct bpf_array, map); struct perf_event *event; + struct file *file; if (unlikely(index >= array->map.max_entries)) return -E2BIG; - event = (struct perf_event *)array->ptrs[index]; - if (!event) + file = (struct file *)array->ptrs[index]; + if (unlikely(!file)) return -ENOENT; + event = file->private_data; + /* make sure event is local and doesn't have pmu::count */ if (event->oncpu != smp_processor_id() || event->pmu->count) @@ -228,6 +231,7 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 index, u64 r4, u64 size) void *data = (void *) (long) r4; struct perf_sample_data sample_data; struct perf_event *event; + struct file *file; struct perf_raw_record raw = { .size = size, .data = data, @@ -236,10 +240,12 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 index, u64 r4, u64 size) if (unlikely(index >= array->map.max_entries)) return -E2BIG; - event = (struct perf_event *)array->ptrs[index]; - if (unlikely(!event)) + file = (struct file *)array->ptrs[index]; + if (unlikely(!file)) return -ENOENT; + event = file->private_data; + if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE || event->attr.config != PERF_COUNT_SW_BPF_OUTPUT)) return -EINVAL; -- cgit v1.2.3 From 6ccd83714a009ee301b50c15f6c3a5dc1f30164c Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 29 Jan 2016 10:22:41 -0500 Subject: tracing/stacktrace: Show entire trace if passed in function not found When a max stack trace is discovered, the stack dump is saved. In order to not record the overhead of the stack tracer, the ip of the traced function is looked for within the dump. The trace is started from the location of that function. But if for some reason the ip is not found, the entire stack trace is then truncated. That's not very useful. Instead, print everything if the ip of the traced function is not found within the trace. This issue showed up on s390. Link: http://lkml.kernel.org/r/20160129102241.1b3c9c04@gandalf.local.home Fixes: 72ac426a5bb0 ("tracing: Clean up stack tracing and fix fentry updates") Cc: stable@vger.kernel.org # v4.3+ Reported-by: Heiko Carstens Tested-by: Heiko Carstens Signed-off-by: Steven Rostedt --- kernel/trace/trace_stack.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel/trace') diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index dda9e6742950..202df6cffcca 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -125,6 +125,13 @@ check_stack(unsigned long ip, unsigned long *stack) break; } + /* + * Some archs may not have the passed in ip in the dump. + * If that happens, we need to show everything. + */ + if (i == stack_trace_max.nr_entries) + i = 0; + /* * Now find where in the stack these are. */ -- cgit v1.2.3