diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/ftrace_event.h | 9 | ||||
| -rw-r--r-- | include/trace/ftrace.h | 39 |
2 files changed, 37 insertions, 11 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index f7b47c336703..43360c1d8f70 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -137,8 +137,13 @@ struct ftrace_event_call { #define FTRACE_MAX_PROFILE_SIZE 2048 -extern char *trace_profile_buf; -extern char *trace_profile_buf_nmi; +struct perf_trace_buf { + char buf[FTRACE_MAX_PROFILE_SIZE]; + int recursion; +}; + +extern struct perf_trace_buf *perf_trace_buf; +extern struct perf_trace_buf *perf_trace_buf_nmi; #define MAX_FILTER_PRED 32 #define MAX_FILTER_STR_VAL 256 /* Should handle KSYM_SYMBOL_LEN */ diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index a7f946094128..4945d1c99864 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -649,6 +649,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ * struct ftrace_event_call *event_call = &event_<call>; * extern void perf_tp_event(int, u64, u64, void *, int); * struct ftrace_raw_##call *entry; + * struct perf_trace_buf *trace_buf; * u64 __addr = 0, __count = 1; * unsigned long irq_flags; * struct trace_entry *ent; @@ -673,14 +674,25 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ * __cpu = smp_processor_id(); * * if (in_nmi()) - * raw_data = rcu_dereference(trace_profile_buf_nmi); + * trace_buf = rcu_dereference(perf_trace_buf_nmi); * else - * raw_data = rcu_dereference(trace_profile_buf); + * trace_buf = rcu_dereference(perf_trace_buf); * - * if (!raw_data) + * if (!trace_buf) * goto end; * - * raw_data = per_cpu_ptr(raw_data, __cpu); + * trace_buf = per_cpu_ptr(trace_buf, __cpu); + * + * // Avoid recursion from perf that could mess up the buffer + * if (trace_buf->recursion++) + * goto end_recursion; + * + * raw_data = trace_buf->buf; + * + * // Make recursion update visible before entering perf_tp_event + * // so that we protect from perf recursions. + * + * barrier(); * * //zero dead bytes from alignment to avoid stack leak to userspace: * *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; @@ -713,8 +725,9 @@ static void ftrace_profile_##call(proto) \ { \ struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\ struct ftrace_event_call *event_call = &event_##call; \ - extern void perf_tp_event(int, u64, u64, void *, int); \ + extern void perf_tp_event(int, u64, u64, void *, int); \ struct ftrace_raw_##call *entry; \ + struct perf_trace_buf *trace_buf; \ u64 __addr = 0, __count = 1; \ unsigned long irq_flags; \ struct trace_entry *ent; \ @@ -739,14 +752,20 @@ static void ftrace_profile_##call(proto) \ __cpu = smp_processor_id(); \ \ if (in_nmi()) \ - raw_data = rcu_dereference(trace_profile_buf_nmi); \ + trace_buf = rcu_dereference(perf_trace_buf_nmi); \ else \ - raw_data = rcu_dereference(trace_profile_buf); \ + trace_buf = rcu_dereference(perf_trace_buf); \ \ - if (!raw_data) \ + if (!trace_buf) \ goto end; \ \ - raw_data = per_cpu_ptr(raw_data, __cpu); \ + trace_buf = per_cpu_ptr(trace_buf, __cpu); \ + if (trace_buf->recursion++) \ + goto end_recursion; \ + \ + barrier(); \ + \ + raw_data = trace_buf->buf; \ \ *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; \ entry = (struct ftrace_raw_##call *)raw_data; \ @@ -761,6 +780,8 @@ static void ftrace_profile_##call(proto) \ perf_tp_event(event_call->id, __addr, __count, entry, \ __entry_size); \ \ +end_recursion: \ + trace_buf->recursion--; \ end: \ local_irq_restore(irq_flags); \ \ |