[tip:perf/core] perf trace beauty kcmp: Beautify arguments

From: tip-bot for Arnaldo Carvalho de Melo
Date: Fri Nov 03 2017 - 10:25:37 EST

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Commit-ID: 1de3038d0082a1c2edd7a7b1b3381e38f42af0e7
Gitweb: https://git.kernel.org/tip/1de3038d0082a1c2edd7a7b1b3381e38f42af0e7
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 31 Oct 2017 11:32:23 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 31 Oct 2017 16:17:04 -0300

perf trace beauty kcmp: Beautify arguments

For some unknown reason there is no entry in tracefs's syscalls for
kcmp, i.e. no tracefs/events/syscalls/sys_{enter,exit}_kcmp, so we need
to provide a data dictionary for the fields.

To beautify the 'type' argument we automatically generate a strarray
from tools/include/uapi/kcmp.h, the idx1 and idx2 args, nowadays used
only if type == KCMP_FILE, are masked for all the other types and a
lookup is made for the thread and fd to show the path, if possible,
getting it from the probe:vfs_getname if in place or from procfs, races
allowing.

A system wide strace like tracing session, with callchains shows just
one user so far in this fedora 25 machine:

# perf trace --max-stack 5 -e kcmp
<SNIP>
1502914.400 ( 0.001 ms): systemd/1 kcmp(pid1: 1 (systemd), pid2: 1 (systemd), type: FILE, idx1: 271<socket:[4723475]>, idx2: 25<socket:[4788686]>) = -1 ENOSYS Function not implemented
syscall (/usr/lib64/libc-2.25.so)
same_fd (/usr/lib/systemd/libsystemd-shared-233.so)
service_add_fd_store (/usr/lib/systemd/systemd)
service_notify_message.lto_priv.127 (/usr/lib/systemd/systemd)
1502914.407 ( 0.001 ms): systemd/1 kcmp(pid1: 1 (systemd), pid2: 1 (systemd), type: FILE, idx1: 270<socket:[4726396]>, idx2: 25<socket:[4788686]>) = -1 ENOSYS Function not implemented
syscall (/usr/lib64/libc-2.25.so)
same_fd (/usr/lib/systemd/libsystemd-shared-233.so)
service_add_fd_store (/usr/lib/systemd/systemd)
service_notify_message.lto_priv.127 (/usr/lib/systemd/systemd)
<SNIP>

The backtraces seem to agree this is really kcmp(), but this system
doesn't have the sys_kcmp(), bummer:

# uname -a
Linux jouet 4.14.0-rc3+ #1 SMP Fri Oct 13 12:21:12 -03 2017 x86_64 x86_64 x86_64 GNU/Linux
# grep kcmp /proc/kallsyms
ffffffffb60b8890 W sys_kcmp
$ grep CONFIG_CHECKPOINT_RESTORE ../build/v4.14.0-rc3+/.config
# CONFIG_CHECKPOINT_RESTORE is not set
$

So systemd uses it, good fedora kernel config has it:

$ grep CONFIG_CHECKPOINT_RESTORE /boot/config-4.13.4-200.fc26.x86_64
CONFIG_CHECKPOINT_RESTORE=y
[acme@jouet linux]$

/me goes to rebuild a kernel...

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Andrey Vagin <avagin@xxxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-gz5fca968viw8m7hryjqvrln@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/Makefile.perf | 9 ++++++++
tools/perf/builtin-trace.c | 6 +++++
tools/perf/trace/beauty/Build | 1 +
tools/perf/trace/beauty/beauty.h | 6 +++++
tools/perf/trace/beauty/kcmp.c | 44 ++++++++++++++++++++++++++++++++++++
tools/perf/trace/beauty/kcmp_type.sh | 10 ++++++++
6 files changed, 76 insertions(+)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index c872ca6..68cf136 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -420,6 +420,13 @@ sndrv_pcm_ioctl_tbl := $(srctree)/tools/perf/trace/beauty/sndrv_pcm_ioctl.sh
$(sndrv_pcm_ioctl_array): $(sndrv_pcm_hdr_dir)/asound.h $(sndrv_pcm_ioctl_tbl)
$(Q)$(SHELL) '$(sndrv_pcm_ioctl_tbl)' $(sndrv_pcm_hdr_dir) > $@

+kcmp_type_array := $(beauty_outdir)/kcmp_type_array.c
+kcmp_hdr_dir := $(srctree)/tools/include/uapi/linux/
+kcmp_type_tbl := $(srctree)/tools/perf/trace/beauty/kcmp_type.sh
+
+$(kcmp_type_array): $(kcmp_hdr_dir)/kcmp.h $(kcmp_type_tbl)
+ $(Q)$(SHELL) '$(kcmp_type_tbl)' $(kcmp_hdr_dir) > $@
+
kvm_ioctl_array := $(beauty_ioctl_outdir)/kvm_ioctl_array.c
kvm_hdr_dir := $(srctree)/tools/include/uapi/linux
kvm_ioctl_tbl := $(srctree)/tools/perf/trace/beauty/kvm_ioctl.sh
@@ -553,6 +560,7 @@ prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h archheaders $(drm_ioc
$(pkey_alloc_access_rights_array) \
$(sndrv_pcm_ioctl_array) \
$(sndrv_ctl_ioctl_array) \
+ $(kcmp_type_array) \
$(kvm_ioctl_array) \
$(vhost_virtio_ioctl_array) \
$(madvise_behavior_array) \
@@ -836,6 +844,7 @@ clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clea
$(OUTPUT)$(sndrv_ctl_ioctl_array) \
$(OUTPUT)$(sndrv_pcm_ioctl_array) \
$(OUTPUT)$(kvm_ioctl_array) \
+ $(OUTPUT)$(kcmp_type_array) \
$(OUTPUT)$(vhost_virtio_ioctl_array) \
$(OUTPUT)$(perf_ioctl_array) \
$(OUTPUT)$(prctl_option_array)
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 0c14614..505b871 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -633,6 +633,12 @@ static struct syscall_fmt {
#else
[2] = { .scnprintf = SCA_HEX, /* arg */ }, }, },
#endif
+ { .name = "kcmp", .nr_args = 5,
+ .arg = { [0] = { .name = "pid1", .scnprintf = SCA_PID, },
+ [1] = { .name = "pid2", .scnprintf = SCA_PID, },
+ [2] = { .name = "type", .scnprintf = SCA_KCMP_TYPE, },
+ [3] = { .name = "idx1", .scnprintf = SCA_KCMP_IDX, },
+ [4] = { .name = "idx2", .scnprintf = SCA_KCMP_IDX, }, }, },
{ .name = "keyctl",
.arg = { [0] = STRARRAY(option, keyctl_options), }, },
{ .name = "kill",
diff --git a/tools/perf/trace/beauty/Build b/tools/perf/trace/beauty/Build
index 2f68b76..066bbf0 100644
--- a/tools/perf/trace/beauty/Build
+++ b/tools/perf/trace/beauty/Build
@@ -3,6 +3,7 @@ libperf-y += fcntl.o
ifeq ($(SRCARCH),$(filter $(SRCARCH),x86))
libperf-y += ioctl.o
endif
+libperf-y += kcmp.o
libperf-y += pkey_alloc.o
libperf-y += prctl.o
libperf-y += statx.o
diff --git a/tools/perf/trace/beauty/beauty.h b/tools/perf/trace/beauty/beauty.h
index 365bb6f..3f067bd 100644
--- a/tools/perf/trace/beauty/beauty.h
+++ b/tools/perf/trace/beauty/beauty.h
@@ -81,6 +81,12 @@ size_t syscall_arg__scnprintf_fcntl_arg(char *bf, size_t size, struct syscall_ar
size_t syscall_arg__scnprintf_ioctl_cmd(char *bf, size_t size, struct syscall_arg *arg);
#define SCA_IOCTL_CMD syscall_arg__scnprintf_ioctl_cmd

+size_t syscall_arg__scnprintf_kcmp_type(char *bf, size_t size, struct syscall_arg *arg);
+#define SCA_KCMP_TYPE syscall_arg__scnprintf_kcmp_type
+
+size_t syscall_arg__scnprintf_kcmp_idx(char *bf, size_t size, struct syscall_arg *arg);
+#define SCA_KCMP_IDX syscall_arg__scnprintf_kcmp_idx
+
size_t syscall_arg__scnprintf_pkey_alloc_access_rights(char *bf, size_t size, struct syscall_arg *arg);
#define SCA_PKEY_ALLOC_ACCESS_RIGHTS syscall_arg__scnprintf_pkey_alloc_access_rights

diff --git a/tools/perf/trace/beauty/kcmp.c b/tools/perf/trace/beauty/kcmp.c
new file mode 100644
index 0000000..f62040e
--- /dev/null
+++ b/tools/perf/trace/beauty/kcmp.c
@@ -0,0 +1,44 @@
+/*
+ * trace/beauty/kcmp.c
+ *
+ * Copyright (C) 2017, Red Hat Inc, Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
+ *
+ * Released under the GPL v2. (and only v2, not any later version)
+ */
+
+#include "trace/beauty/beauty.h"
+#include <linux/kernel.h>
+#include <sys/types.h>
+#include <machine.h>
+#include <uapi/linux/kcmp.h>
+
+#include "trace/beauty/generated/kcmp_type_array.c"
+
+size_t syscall_arg__scnprintf_kcmp_idx(char *bf, size_t size, struct syscall_arg *arg)
+{
+ unsigned long fd = arg->val;
+ int type = syscall_arg__val(arg, 2);
+ pid_t pid;
+
+ if (type != KCMP_FILE)
+ return syscall_arg__scnprintf_long(bf, size, arg);
+
+ pid = syscall_arg__val(arg, arg->idx == 3 ? 0 : 1); /* idx1 -> pid1, idx2 -> pid2 */
+ return pid__scnprintf_fd(arg->trace, pid, fd, bf, size);
+}
+
+static size_t kcmp__scnprintf_type(int type, char *bf, size_t size)
+{
+ static DEFINE_STRARRAY(kcmp_types);
+ return strarray__scnprintf(&strarray__kcmp_types, bf, size, "%d", type);
+}
+
+size_t syscall_arg__scnprintf_kcmp_type(char *bf, size_t size, struct syscall_arg *arg)
+{
+ unsigned long type = arg->val;
+
+ if (type != KCMP_FILE)
+ arg->mask |= (1 << 3) | (1 << 4); /* Ignore idx1 and idx2 */
+
+ return kcmp__scnprintf_type(type, bf, size);
+}
diff --git a/tools/perf/trace/beauty/kcmp_type.sh b/tools/perf/trace/beauty/kcmp_type.sh
new file mode 100755
index 0000000..40d063b8
--- /dev/null
+++ b/tools/perf/trace/beauty/kcmp_type.sh
@@ -0,0 +1,10 @@
+#!/bin/sh
+
+header_dir=$1
+
+printf "static const char *kcmp_types[] = {\n"
+regex='^[[:space:]]+(KCMP_(\w+)),'
+egrep $regex ${header_dir}/kcmp.h | grep -v KCMP_TYPES, | \
+ sed -r "s/$regex/\1 \2/g" | \
+ xargs printf "\t[%s]\t= \"%s\",\n"
+printf "};\n"

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Previous message: Herbert Xu: "Re: [PATCH] crypto: vmx - Use skcipher for ctr fallback"
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