From f4e2298e63d24bb7f5cf0f56f72867973cb7e652 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 13 Dec 2017 10:35:37 -0800 Subject: [PATCH] bpf/tracing: fix kernel/events/core.c compilation error Commit f371b304f12e ("bpf/tracing: allow user space to query prog array on the same tp") introduced a perf ioctl command to query prog array attached to the same perf tracepoint. The commit introduced a compilation error under certain config conditions, e.g., (1). CONFIG_BPF_SYSCALL is not defined, or (2). CONFIG_TRACING is defined but neither CONFIG_UPROBE_EVENTS nor CONFIG_KPROBE_EVENTS is defined. Error message: kernel/events/core.o: In function `perf_ioctl': core.c:(.text+0x98c4): undefined reference to `bpf_event_query_prog_array' This patch fixed this error by guarding the real definition under CONFIG_BPF_EVENTS and provided static inline dummy function if CONFIG_BPF_EVENTS was not defined. It renamed the function from bpf_event_query_prog_array to perf_event_query_prog_array and moved the definition from linux/bpf.h to linux/trace_events.h so the definition is in proximity to other prog_array related functions. Fixes: f371b304f12e ("bpf/tracing: allow user space to query prog array on the same tp") Reported-by: Stephen Rothwell Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann --- include/linux/bpf.h | 1 - include/linux/trace_events.h | 6 ++++++ kernel/events/core.c | 2 +- kernel/trace/bpf_trace.c | 2 +- 4 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 93e15b9d80c7..54dc7cae2949 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -254,7 +254,6 @@ typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src, u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy); -int bpf_event_query_prog_array(struct perf_event *event, void __user *info); int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, union bpf_attr __user *uattr); diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 5fea451f6e28..8a1442c4e513 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -467,6 +467,7 @@ trace_trigger_soft_disabled(struct trace_event_file *file) unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx); int perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog); void perf_event_detach_bpf_prog(struct perf_event *event); +int perf_event_query_prog_array(struct perf_event *event, void __user *info); #else static inline unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) { @@ -481,6 +482,11 @@ perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog) static inline void perf_event_detach_bpf_prog(struct perf_event *event) { } +static inline int +perf_event_query_prog_array(struct perf_event *event, void __user *info) +{ + return -EOPNOTSUPP; +} #endif enum { diff --git a/kernel/events/core.c b/kernel/events/core.c index 5857c500721b..34fda6aa4606 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4725,7 +4725,7 @@ static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned lon } case PERF_EVENT_IOC_QUERY_BPF: - return bpf_event_query_prog_array(event, (void __user *)arg); + return perf_event_query_prog_array(event, (void __user *)arg); default: return -ENOTTY; } diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e009b7ecf473..c5dd60cc0751 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -856,7 +856,7 @@ unlock: mutex_unlock(&bpf_event_mutex); } -int bpf_event_query_prog_array(struct perf_event *event, void __user *info) +int perf_event_query_prog_array(struct perf_event *event, void __user *info) { struct perf_event_query_bpf __user *uquery = info; struct perf_event_query_bpf query = {}; -- 2.11.0