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authorQuentin Monnet <quentin@isovalent.com>2020-03-11 05:12:05 +0300
committerAlexei Starovoitov <ast@kernel.org>2020-03-13 22:49:51 +0300
commit6ae32b29c09ba9b99c4c7317eed029587bd2706d (patch)
tree416d031bf3a6a30aa91782505b8716b2aae55fb0 /tools/bpf
parentd831ee84bfc9173eecf30dbbc2553ae81b996c60 (diff)
downloadlinux-6ae32b29c09ba9b99c4c7317eed029587bd2706d.tar.xz
tools: bpftool: Restore message on failure to guess program type
In commit 4a3d6c6a6e4d ("libbpf: Reduce log level for custom section names"), log level for messages for libbpf_attach_type_by_name() and libbpf_prog_type_by_name() was downgraded from "info" to "debug". The latter function, in particular, is used by bpftool when attempting to load programs, and this change caused bpftool to exit with no hint or error message when it fails to detect the type of the program to load (unless "-d" option was provided). To help users understand why bpftool fails to load the program, let's do a second run of the function with log level in "debug" mode in case of failure. Before: # bpftool prog load sample_ret0.o /sys/fs/bpf/sample_ret0 # echo $? 255 Or really verbose with -d flag: # bpftool -d prog load sample_ret0.o /sys/fs/bpf/sample_ret0 libbpf: loading sample_ret0.o libbpf: section(1) .strtab, size 134, link 0, flags 0, type=3 libbpf: skip section(1) .strtab libbpf: section(2) .text, size 16, link 0, flags 6, type=1 libbpf: found program .text libbpf: section(3) .debug_abbrev, size 55, link 0, flags 0, type=1 libbpf: skip section(3) .debug_abbrev libbpf: section(4) .debug_info, size 75, link 0, flags 0, type=1 libbpf: skip section(4) .debug_info libbpf: section(5) .rel.debug_info, size 32, link 14, flags 0, type=9 libbpf: skip relo .rel.debug_info(5) for section(4) libbpf: section(6) .debug_str, size 150, link 0, flags 30, type=1 libbpf: skip section(6) .debug_str libbpf: section(7) .BTF, size 155, link 0, flags 0, type=1 libbpf: section(8) .BTF.ext, size 80, link 0, flags 0, type=1 libbpf: section(9) .rel.BTF.ext, size 32, link 14, flags 0, type=9 libbpf: skip relo .rel.BTF.ext(9) for section(8) libbpf: section(10) .debug_frame, size 40, link 0, flags 0, type=1 libbpf: skip section(10) .debug_frame libbpf: section(11) .rel.debug_frame, size 16, link 14, flags 0, type=9 libbpf: skip relo .rel.debug_frame(11) for section(10) libbpf: section(12) .debug_line, size 74, link 0, flags 0, type=1 libbpf: skip section(12) .debug_line libbpf: section(13) .rel.debug_line, size 16, link 14, flags 0, type=9 libbpf: skip relo .rel.debug_line(13) for section(12) libbpf: section(14) .symtab, size 96, link 1, flags 0, type=2 libbpf: looking for externs among 4 symbols... libbpf: collected 0 externs total libbpf: failed to guess program type from ELF section '.text' libbpf: supported section(type) names are: socket sk_reuseport kprobe/ [...] After: # bpftool prog load sample_ret0.o /sys/fs/bpf/sample_ret0 libbpf: failed to guess program type from ELF section '.text' libbpf: supported section(type) names are: socket sk_reuseport kprobe/ [...] Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200311021205.9755-1-quentin@isovalent.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/bpf')
-rw-r--r--tools/bpf/bpftool/common.c7
-rw-r--r--tools/bpf/bpftool/main.c7
-rw-r--r--tools/bpf/bpftool/main.h5
-rw-r--r--tools/bpf/bpftool/prog.c27
4 files changed, 35 insertions, 11 deletions
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index ad634516ba80..f2223dbdfb0a 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -572,3 +572,10 @@ int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what)
return 0;
}
+
+int __printf(2, 0)
+print_all_levels(__maybe_unused enum libbpf_print_level level,
+ const char *format, va_list args)
+{
+ return vfprintf(stderr, format, args);
+}
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 6d41bbfc6459..06449e846e4b 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -79,13 +79,6 @@ static int do_version(int argc, char **argv)
return 0;
}
-static int __printf(2, 0)
-print_all_levels(__maybe_unused enum libbpf_print_level level,
- const char *format, va_list args)
-{
- return vfprintf(stderr, format, args);
-}
-
int cmd_select(const struct cmd *cmds, int argc, char **argv,
int (*help)(int argc, char **argv))
{
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index d57972dd0f2b..5f6dccd43622 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -14,6 +14,8 @@
#include <linux/hashtable.h>
#include <tools/libc_compat.h>
+#include <bpf/libbpf.h>
+
#include "json_writer.h"
#define ptr_to_u64(ptr) ((__u64)(unsigned long)(ptr))
@@ -229,4 +231,7 @@ struct tcmsg;
int do_xdp_dump(struct ifinfomsg *ifinfo, struct nlattr **tb);
int do_filter_dump(struct tcmsg *ifinfo, struct nlattr **tb, const char *kind,
const char *devname, int ifindex);
+
+int print_all_levels(__maybe_unused enum libbpf_print_level level,
+ const char *format, va_list args);
#endif
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index d0966380ad0e..f6a5974a7b0a 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1247,6 +1247,25 @@ free_data_in:
return err;
}
+static int
+get_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
+ enum bpf_attach_type *expected_attach_type)
+{
+ libbpf_print_fn_t print_backup;
+ int ret;
+
+ ret = libbpf_prog_type_by_name(name, prog_type, expected_attach_type);
+ if (!ret)
+ return ret;
+
+ /* libbpf_prog_type_by_name() failed, let's re-run with debug level */
+ print_backup = libbpf_set_print(print_all_levels);
+ ret = libbpf_prog_type_by_name(name, prog_type, expected_attach_type);
+ libbpf_set_print(print_backup);
+
+ return ret;
+}
+
static int load_with_options(int argc, char **argv, bool first_prog_only)
{
enum bpf_prog_type common_prog_type = BPF_PROG_TYPE_UNSPEC;
@@ -1296,8 +1315,8 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
strcat(type, *argv);
strcat(type, "/");
- err = libbpf_prog_type_by_name(type, &common_prog_type,
- &expected_attach_type);
+ err = get_prog_type_by_name(type, &common_prog_type,
+ &expected_attach_type);
free(type);
if (err < 0)
goto err_free_reuse_maps;
@@ -1396,8 +1415,8 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
if (prog_type == BPF_PROG_TYPE_UNSPEC) {
const char *sec_name = bpf_program__title(pos, false);
- err = libbpf_prog_type_by_name(sec_name, &prog_type,
- &expected_attach_type);
+ err = get_prog_type_by_name(sec_name, &prog_type,
+ &expected_attach_type);
if (err < 0)
goto err_close_obj;
}