[PATCH 0/4] [GIT PULL] tracing, kprobes: Fix kprobe symbol offset (for minus)

[PATCH 0/4] [GIT PULL] tracing, kprobes: Fix kprobe symbol offset (for minus)

[Steven Rostedt]

Linus,

The documentation for kprobe events says that symbol offets can
take both a + and - sign to get to before and after the symbol address.
But in actuality, the code does not support the minus. This fixes
that issue, and adds a few more selftests to kprobe events.

Please pull the latest trace-v4.16-rc4 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v4.16-rc4

Tag SHA1: d92df88947baacdf2ebfe80871fb1c6f9211aa80
Head SHA1: dfa453bc90eca0febff33c8d292a656e53702158


Masami Hiramatsu (4):
      tracing: probeevent: Fix to support minus offset from symbol
      selftests: ftrace: Add probe event argument syntax testcase
      selftests: ftrace: Add a testcase for string type with kprobe_event
      selftests: ftrace: Add a testcase for probepoint

----
 kernel/trace/trace_kprobe.c                        |  4 +-
 kernel/trace/trace_probe.c                         |  8 +-
 kernel/trace/trace_probe.h                         |  2 +-
 .../ftrace/test.d/kprobe/kprobe_args_string.tc     | 46 ++++++++++
 .../ftrace/test.d/kprobe/kprobe_args_syntax.tc     | 97 ++++++++++++++++++++++
 .../selftests/ftrace/test.d/kprobe/probepoint.tc   | 43 ++++++++++
 6 files changed, 192 insertions(+), 8 deletions(-)
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc

[PATCH 1/4] tracing: probeevent: Fix to support minus offset from symbol

[Steven Rostedt]

[-- Attachment #1: 0001-tracing-probeevent-Fix-to-support-minus-offset-from-.patch --]
[-- Type: text/plain, Size: 3539 bytes --]

From: Masami Hiramatsu <mhiramat@kernel.org>

In Documentation/trace/kprobetrace.txt, it says

 @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)

However, the parser doesn't parse minus offset correctly, since
commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
unsigned") drops minus ("-") offset support for kprobe probe
address usage.

This fixes the traceprobe_split_symbol_offset() to parse minus
offset again with checking the offset range, and add a minus
offset check in kprobe probe address usage.

Link: http://lkml.kernel.org/r/152129028983.31874.13419301530285775521.stgit@devbox

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned")
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 4 ++--
 kernel/trace/trace_probe.c  | 8 +++-----
 kernel/trace/trace_probe.h  | 2 +-
 3 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 1fad24acd444..ae4147eaebd4 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -659,7 +659,7 @@ static int create_trace_kprobe(int argc, char **argv)
 	char *symbol = NULL, *event = NULL, *group = NULL;
 	int maxactive = 0;
 	char *arg;
-	unsigned long offset = 0;
+	long offset = 0;
 	void *addr = NULL;
 	char buf[MAX_EVENT_NAME_LEN];
 
@@ -747,7 +747,7 @@ static int create_trace_kprobe(int argc, char **argv)
 		symbol = argv[1];
 		/* TODO: support .init module functions */
 		ret = traceprobe_split_symbol_offset(symbol, &offset);
-		if (ret) {
+		if (ret || offset < 0 || offset > UINT_MAX) {
 			pr_info("Failed to parse either an address or a symbol.\n");
 			return ret;
 		}
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index d59357308677..daf54bda4dc8 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -320,7 +320,7 @@ static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
 }
 
 /* Split symbol and offset. */
-int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
+int traceprobe_split_symbol_offset(char *symbol, long *offset)
 {
 	char *tmp;
 	int ret;
@@ -328,13 +328,11 @@ int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
 	if (!offset)
 		return -EINVAL;
 
-	tmp = strchr(symbol, '+');
+	tmp = strpbrk(symbol, "+-");
 	if (tmp) {
-		/* skip sign because kstrtoul doesn't accept '+' */
-		ret = kstrtoul(tmp + 1, 0, offset);
+		ret = kstrtol(tmp, 0, offset);
 		if (ret)
 			return ret;
-
 		*tmp = '\0';
 	} else
 		*offset = 0;
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index e101c5bb9eda..6a4d3fa94042 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -365,7 +365,7 @@ extern int traceprobe_conflict_field_name(const char *name,
 extern void traceprobe_update_arg(struct probe_arg *arg);
 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 
-extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);
+extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
 
 /* Sum up total data length for dynamic arraies (strings) */
 static nokprobe_inline int
-- 
2.15.1

[PATCH 2/4] selftests: ftrace: Add probe event argument syntax testcase

[Steven Rostedt]

[-- Attachment #1: 0002-selftests-ftrace-Add-probe-event-argument-syntax-tes.patch --]
[-- Type: text/plain, Size: 3135 bytes --]

From: Masami Hiramatsu <mhiramat@kernel.org>

Add a testcase for probe event argument syntax which
ensures the kprobe_events interface correctly parses
given event arguments.

Link: http://lkml.kernel.org/r/152129033679.31874.12705519603869152799.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../ftrace/test.d/kprobe/kprobe_args_syntax.tc     | 97 ++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc
new file mode 100644
index 000000000000..231bcd2c4eb5
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc
@@ -0,0 +1,97 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Kprobe event argument syntax
+
+[ -f kprobe_events ] || exit_unsupported # this is configurable
+
+grep "x8/16/32/64" README > /dev/null || exit_unsupported # version issue
+
+echo 0 > events/enable
+echo > kprobe_events
+
+PROBEFUNC="vfs_read"
+GOODREG=
+BADREG=
+GOODSYM="_sdata"
+if ! grep -qw ${GOODSYM} /proc/kallsyms ; then
+  GOODSYM=$PROBEFUNC
+fi
+BADSYM="deaqswdefr"
+SYMADDR=0x`grep -w ${GOODSYM} /proc/kallsyms | cut -f 1 -d " "`
+GOODTYPE="x16"
+BADTYPE="y16"
+
+case `uname -m` in
+x86_64|i[3456]86)
+  GOODREG=%ax
+  BADREG=%ex
+;;
+aarch64)
+  GOODREG=%x0
+  BADREG=%ax
+;;
+arm*)
+  GOODREG=%r0
+  BADREG=%ax
+;;
+esac
+
+test_goodarg() # Good-args
+{
+  while [ "$1" ]; do
+    echo "p ${PROBEFUNC} $1" > kprobe_events
+    shift 1
+  done;
+}
+
+test_badarg() # Bad-args
+{
+  while [ "$1" ]; do
+    ! echo "p ${PROBEFUNC} $1" > kprobe_events
+    shift 1
+  done;
+}
+
+echo > kprobe_events
+
+: "Register access"
+test_goodarg ${GOODREG}
+test_badarg ${BADREG}
+
+: "Symbol access"
+test_goodarg "@${GOODSYM}" "@${SYMADDR}" "@${GOODSYM}+10" "@${GOODSYM}-10"
+test_badarg "@" "@${BADSYM}" "@${GOODSYM}*10" "@${GOODSYM}/10" \
+	    "@${GOODSYM}%10" "@${GOODSYM}&10" "@${GOODSYM}|10"
+
+: "Stack access"
+test_goodarg "\$stack" "\$stack0" "\$stack1"
+test_badarg "\$stackp" "\$stack0+10" "\$stack1-10"
+
+: "Retval access"
+echo "r ${PROBEFUNC} \$retval" > kprobe_events
+! echo "p ${PROBEFUNC} \$retval" > kprobe_events
+
+: "Comm access"
+test_goodarg "\$comm"
+
+: "Indirect memory access"
+test_goodarg "+0(${GOODREG})" "-0(${GOODREG})" "+10(\$stack)" \
+	"+0(\$stack1)" "+10(@${GOODSYM}-10)" "+0(+10(+20(\$stack)))"
+test_badarg "+(${GOODREG})" "(${GOODREG}+10)" "-(${GOODREG})" "(${GOODREG})" \
+	"+10(\$comm)" "+0(${GOODREG})+10"
+
+: "Name assignment"
+test_goodarg "varname=${GOODREG}"
+test_badarg "varname=varname2=${GOODREG}"
+
+: "Type syntax"
+test_goodarg "${GOODREG}:${GOODTYPE}"
+test_badarg "${GOODREG}::${GOODTYPE}" "${GOODREG}:${BADTYPE}" \
+	"${GOODTYPE}:${GOODREG}"
+
+: "Combination check"
+
+test_goodarg "\$comm:string" "+0(\$stack):string"
+test_badarg "\$comm:x64" "\$stack:string" "${GOODREG}:string"
+
+echo > kprobe_events
-- 
2.15.1

[PATCH 3/4] selftests: ftrace: Add a testcase for string type with kprobe_event

[Steven Rostedt]

[-- Attachment #1: 0003-selftests-ftrace-Add-a-testcase-for-string-type-with.patch --]
[-- Type: text/plain, Size: 1995 bytes --]

From: Masami Hiramatsu <mhiramat@kernel.org>

Add a testcase for string type with kprobe event.
This tests good/bad syntax combinations and also
the traced data is correct in several way.

Link: http://lkml.kernel.org/r/152129038381.31874.9201387794548737554.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../ftrace/test.d/kprobe/kprobe_args_string.tc     | 46 ++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
new file mode 100644
index 000000000000..5ba73035e1d9
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
@@ -0,0 +1,46 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Kprobe event string type argument
+
+[ -f kprobe_events ] || exit_unsupported # this is configurable
+
+echo 0 > events/enable
+echo > kprobe_events
+
+case `uname -m` in
+x86_64)
+  ARG2=%si
+  OFFS=8
+;;
+i[3456]86)
+  ARG2=%cx
+  OFFS=4
+;;
+aarch64)
+  ARG2=%x1
+  OFFS=8
+;;
+arm*)
+  ARG2=%r1
+  OFFS=4
+;;
+*)
+  echo "Please implement other architecture here"
+  exit_untested
+esac
+
+: "Test get argument (1)"
+echo "p:testprobe create_trace_kprobe arg1=+0(+0(${ARG2})):string" > kprobe_events
+echo 1 > events/kprobes/testprobe/enable
+! echo test >> kprobe_events
+tail -n 1 trace | grep -qe "testprobe.* arg1=\"test\""
+
+echo 0 > events/kprobes/testprobe/enable
+: "Test get argument (2)"
+echo "p:testprobe create_trace_kprobe arg1=+0(+0(${ARG2})):string arg2=+0(+${OFFS}(${ARG2})):string" > kprobe_events
+echo 1 > events/kprobes/testprobe/enable
+! echo test1 test2 >> kprobe_events
+tail -n 1 trace | grep -qe "testprobe.* arg1=\"test1\" arg2=\"test2\""
+
+echo 0 > events/enable
+echo > kprobe_events
-- 
2.15.1

[PATCH 4/4] selftests: ftrace: Add a testcase for probepoint

[Steven Rostedt]

[-- Attachment #1: 0004-selftests-ftrace-Add-a-testcase-for-probepoint.patch --]
[-- Type: text/plain, Size: 2198 bytes --]

From: Masami Hiramatsu <mhiramat@kernel.org>

Add a testcase for probe point definition. This tests
symbol, address and symbol+offset syntax. The offset
must be positive and smaller than UINT_MAX.

Link: http://lkml.kernel.org/r/152129043097.31874.14273580606301767394.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../selftests/ftrace/test.d/kprobe/probepoint.tc   | 43 ++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc b/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc
new file mode 100644
index 000000000000..4fda01a08da4
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc
@@ -0,0 +1,43 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Kprobe events - probe points
+
+[ -f kprobe_events ] || exit_unsupported # this is configurable
+
+TARGET_FUNC=create_trace_kprobe
+
+dec_addr() { # hexaddr
+  printf "%d" "0x"`echo $1 | tail -c 8`
+}
+
+set_offs() { # prev target next
+  A1=`dec_addr $1`
+  A2=`dec_addr $2`
+  A3=`dec_addr $3`
+  TARGET="0x$2" # an address
+  PREV=`expr $A1 - $A2` # offset to previous symbol
+  NEXT=+`expr $A3 - $A2` # offset to next symbol
+  OVERFLOW=+`printf "0x%x" ${PREV}` # overflow offset to previous symbol
+}
+
+# We have to decode symbol addresses to get correct offsets.
+# If the offset is not an instruction boundary, it cause -EILSEQ.
+set_offs `grep -A1 -B1 ${TARGET_FUNC} /proc/kallsyms | cut -f 1 -d " " | xargs`
+
+UINT_TEST=no
+# printf "%x" -1 returns (unsigned long)-1.
+if [ `printf "%x" -1 | wc -c` != 9 ]; then
+  UINT_TEST=yes
+fi
+
+echo 0 > events/enable
+echo > kprobe_events
+echo "p:testprobe ${TARGET_FUNC}" > kprobe_events
+echo "p:testprobe ${TARGET}" > kprobe_events
+echo "p:testprobe ${TARGET_FUNC}${NEXT}" > kprobe_events
+! echo "p:testprobe ${TARGET_FUNC}${PREV}" > kprobe_events
+if [ "${UINT_TEST}" = yes ]; then
+! echo "p:testprobe ${TARGET_FUNC}${OVERFLOW}" > kprobe_events
+fi
+echo > kprobe_events
+clear_trace
-- 
2.15.1