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Date: Mon, 4 Feb 2019 16:20:55 -0800
From: Stanislav Fomichev <sdf@...gle.com>
To: netdev@...r.kernel.org
Cc: yhs@...com, davem@...emloft.net, ast@...nel.org,
daniel@...earbox.net, Stanislav Fomichev <sdf@...gle.com>
Subject: [PATCH bpf-next] libbpf: fix libbpf_print
With the recent print rework we now have the following problem:
pr_{warning,info,debug} expand to __pr which calls libbpf_print.
libbpf_print does va_start and calls __libbpf_pr with va_list argument.
In __base_pr we again do va_start. Because the next argument is a
va_list, we don't get correct pointer to the argument (and print noting
in my case, I don't know why it doesn't crash tbh).
Fix this by changing libbpf_print_fn_t signature to accept va_list and
remove unneeded calls to va_start in the existing users.
Alternatively, this can we solved by exporting __libbpf_pr and
changing __pr macro to (and killing libbpf_print):
{
if (__libbpf_pr)
__libbpf_pr(level, "libbpf: " fmt, ##__VA_ARGS__)
}
Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
---
tools/lib/bpf/libbpf.c | 14 ++++----------
tools/lib/bpf/libbpf.h | 3 +--
tools/perf/util/bpf-loader.c | 10 ++--------
tools/testing/selftests/bpf/test_btf.c | 13 ++-----------
tools/testing/selftests/bpf/test_libbpf_open.c | 10 ++--------
tools/testing/selftests/bpf/test_progs.c | 10 ++--------
6 files changed, 13 insertions(+), 47 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 84ca6c2bea91..47969aa0faf8 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -54,22 +54,16 @@
#define __printf(a, b) __attribute__((format(printf, a, b)))
-__printf(2, 3)
-static int __base_pr(enum libbpf_print_level level, const char *format, ...)
+static int __base_pr(enum libbpf_print_level level, const char *format,
+ va_list args)
{
- va_list args;
- int err;
-
if (level == LIBBPF_DEBUG)
return 0;
- va_start(args, format);
- err = vfprintf(stderr, format, args);
- va_end(args);
- return err;
+ return vfprintf(stderr, format, args);
}
-static __printf(2, 3) libbpf_print_fn_t __libbpf_pr = __base_pr;
+static libbpf_print_fn_t __libbpf_pr = __base_pr;
void libbpf_set_print(libbpf_print_fn_t fn)
{
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 19dbc1bed960..69a7c25eaccc 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -54,8 +54,7 @@ enum libbpf_print_level {
};
typedef int (*libbpf_print_fn_t)(enum libbpf_print_level level,
- const char *, ...)
- __attribute__((format(printf, 2, 3)));
+ const char *, va_list ap);
LIBBPF_API void libbpf_set_print(libbpf_print_fn_t fn);
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 38afdbe6a9e0..037d8ff6a634 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -25,15 +25,9 @@
#include "c++/clang-c.h"
static int libbpf_perf_print(enum libbpf_print_level level __attribute__((unused)),
- const char *fmt, ...)
+ const char *fmt, va_list args)
{
- va_list args;
- int ret;
-
- va_start(args, fmt);
- ret = veprintf(1, verbose, pr_fmt(fmt), args);
- va_end(args);
- return ret;
+ return veprintf(1, verbose, pr_fmt(fmt), args);
}
struct bpf_prog_priv {
diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index aebaeff5a5a0..5afab823ffbe 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -52,19 +52,10 @@ static int count_result(int err)
return err;
}
-#define __printf(a, b) __attribute__((format(printf, a, b)))
-
-__printf(2, 3)
static int __base_pr(enum libbpf_print_level level __attribute__((unused)),
- const char *format, ...)
+ const char *format, va_list args)
{
- va_list args;
- int err;
-
- va_start(args, format);
- err = vfprintf(stderr, format, args);
- va_end(args);
- return err;
+ return vfprintf(stderr, format, args);
}
#define BTF_INFO_ENC(kind, kind_flag, vlen) \
diff --git a/tools/testing/selftests/bpf/test_libbpf_open.c b/tools/testing/selftests/bpf/test_libbpf_open.c
index b9ff3bf76544..1909ecf4d999 100644
--- a/tools/testing/selftests/bpf/test_libbpf_open.c
+++ b/tools/testing/selftests/bpf/test_libbpf_open.c
@@ -36,19 +36,13 @@ static void usage(char *argv[])
static bool debug = 0;
static int libbpf_debug_print(enum libbpf_print_level level,
- const char *fmt, ...)
+ const char *fmt, va_list args)
{
- va_list args;
- int ret;
-
if (level == LIBBPF_DEBUG && !debug)
return 0;
- va_start(args, fmt);
fprintf(stderr, "[%d] ", level);
- ret = vfprintf(stderr, fmt, args);
- va_end(args);
- return ret;
+ return vfprintf(stderr, fmt, args);
}
#define EXIT_FAIL_LIBBPF EXIT_FAILURE
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index 55d05102e7bf..c52bd90fbb34 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -1785,18 +1785,12 @@ static void test_task_fd_query_tp(void)
}
static int libbpf_debug_print(enum libbpf_print_level level,
- const char *format, ...)
+ const char *format, va_list args)
{
- va_list args;
- int ret;
-
if (level == LIBBPF_DEBUG)
return 0;
- va_start(args, format);
- ret = vfprintf(stderr, format, args);
- va_end(args);
- return ret;
+ return vfprintf(stderr, format, args);
}
static void test_reference_tracking()
--
2.20.1.611.gfbb209baf1-goog
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