Commit-ID: 098d2164e3441c252eaa28906d45e16b7bf1bd2b
Gitweb: http://git.kernel.org/tip/098d2164e3441c252eaa28906d45e16b7bf1bd2b
Author: Wang Nan <[email protected]>
AuthorDate: Wed, 1 Jul 2015 02:13:49 +0000
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Thu, 6 Aug 2015 15:27:37 -0300
bpf: Use correct #ifdef controller for trace_call_bpf()
Commit e1abf2cc8d5d80b41c4419368ec743ccadbb131e ("bpf: Fix the build on
BPF_SYSCALL=y && !CONFIG_TRACING kernels, make it more configurable")
updated the building condition of bpf_trace.o from CONFIG_BPF_SYSCALL
to CONFIG_BPF_EVENTS, but the corresponding #ifdef controller in
trace_events.h for trace_call_bpf() was not changed. Which, in theory,
is incorrect.
With current Kconfigs, we can create a .config with CONFIG_BPF_SYSCALL=y
and CONFIG_BPF_EVENTS=n by unselecting CONFIG_KPROBE_EVENT and
selecting CONFIG_BPF_SYSCALL. With these options, trace_call_bpf() will
be defined as an extern function, but if anyone calls it a symbol missing
error will be triggered since bpf_trace.o was not built.
This patch changes the #ifdef controller for trace_call_bpf() from
CONFIG_BPF_SYSCALL to CONFIG_BPF_EVENTS. I'll show its correctness:
Before this patch:
BPF_SYSCALL BPF_EVENTS trace_call_bpf bpf_trace.o
y y normal compiled
n n inline not compiled
y n normal not compiled (incorrect)
n y impossible (BPF_EVENTS depends on BPF_SYSCALL)
After this patch:
BPF_SYSCALL BPF_EVENTS trace_call_bpf bpf_trace.o
y y normal compiled
n n inline not compiled
y n inline not compiled (fixed)
n y impossible (BPF_EVENTS depends on BPF_SYSCALL)
So this patch doesn't break anything. QED.
Signed-off-by: Wang Nan <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David Ahern <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kaixu Xia <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
include/linux/trace_events.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 1063c85..180dbf8 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -542,7 +542,7 @@ event_trigger_unlock_commit_regs(struct trace_event_file
*file,
event_triggers_post_call(file, tt);
}
-#ifdef CONFIG_BPF_SYSCALL
+#ifdef CONFIG_BPF_EVENTS
unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx);
#else
static inline unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
