From 7b6586562708d2b3a04fe49f217ddbadbbbb0546 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Mon, 5 Feb 2018 22:05:31 -0500 Subject: [PATCH 1/6] ftrace: Remove incorrect setting of glob search field __unregister_ftrace_function_probe() will incorrectly parse the glob filter because it resets the search variable that was setup by filter_parse_regex(). Al Viro reported this: After that call of filter_parse_regex() we could have func_g.search not equal to glob only if glob started with '!' or '*'. In the former case we would've buggered off with -EINVAL (not = 1). In the latter we would've set func_g.search equal to glob + 1, calculated the length of that thing in func_g.len and proceeded to reset func_g.search back to glob. Suppose the glob is e.g. *foo*. We end up with func_g.type = MATCH_MIDDLE_ONLY; func_g.len = 3; func_g.search = "*foo"; Feeding that to ftrace_match_record() will not do anything sane - we will be looking for names containing "*foo" (->len is ignored for that one). Link: http://lkml.kernel.org/r/20180127031706.GE13338@ZenIV.linux.org.uk Cc: stable@vger.kernel.org Fixes: 3ba009297149f ("ftrace: Introduce ftrace_glob structure") Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Reviewed-by: Masami Hiramatsu Reported-by: Al Viro Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 1 - 1 file changed, 1 deletion(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index dabd9d167d42..eac9ce2c57a2 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4456,7 +4456,6 @@ unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr, func_g.type = filter_parse_regex(glob, strlen(glob), &func_g.search, ¬); func_g.len = strlen(func_g.search); - func_g.search = glob; /* we do not support '!' for function probes */ if (WARN_ON(not)) From 07234021410bbc27b7c86c18de98616c29fbe667 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Mon, 5 Feb 2018 22:18:11 -0500 Subject: [PATCH 2/6] tracing: Fix parsing of globs with a wildcard at the beginning Al Viro reported: For substring - sure, but what about something like "*a*b" and "a*b"? AFAICS, filter_parse_regex() ends up with identical results in both cases - MATCH_GLOB and *search = "a*b". And no way for the caller to tell one from another. Testing this with the following: # cd /sys/kernel/tracing # echo '*raw*lock' > set_ftrace_filter bash: echo: write error: Invalid argument With this patch: # echo '*raw*lock' > set_ftrace_filter # cat set_ftrace_filter _raw_read_trylock _raw_write_trylock _raw_read_unlock _raw_spin_unlock _raw_write_unlock _raw_spin_trylock _raw_spin_lock _raw_write_lock _raw_read_lock Al recommended not setting the search buffer to skip the first '*' unless we know we are not using MATCH_GLOB. This implements his suggested logic. Link: http://lkml.kernel.org/r/20180127170748.GF13338@ZenIV.linux.org.uk Cc: stable@vger.kernel.org Fixes: 60f1d5e3bac44 ("ftrace: Support full glob matching") Reviewed-by: Masami Hiramatsu Reported-by: Al Viro Suggsted-by: Al Viro Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_filter.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 61e7f0678d33..a764aec3c9a1 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -400,7 +400,6 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not) for (i = 0; i < len; i++) { if (buff[i] == '*') { if (!i) { - *search = buff + 1; type = MATCH_END_ONLY; } else if (i == len - 1) { if (type == MATCH_END_ONLY) @@ -410,14 +409,14 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not) buff[i] = 0; break; } else { /* pattern continues, use full glob */ - type = MATCH_GLOB; - break; + return MATCH_GLOB; } } else if (strchr("[?\\", buff[i])) { - type = MATCH_GLOB; - break; + return MATCH_GLOB; } } + if (buff[0] == '*') + *search = buff + 1; return type; } From df9d36d9e8adefe0975c7b5888967651b3db3af3 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 6 Feb 2018 17:10:12 -0500 Subject: [PATCH 3/6] selftests/ftrace: Have reset_ftrace_filter handle modules If a function probe in set_ftrace_filter belongs to a module, it will contain the module name. Like: wmi_query_block [wmi]:traceoff:unlimited But writing: '!wmi_query_block [wmi]:traceoff' > set_ftrace_filter will cause an error. We still need to write: '!wmi_query_block:traceoff' > set_ftrace_filter Cc: Shuah Khan Signed-off-by: Steven Rostedt (VMware) --- tools/testing/selftests/ftrace/test.d/functions | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions index f2019b37370d..e7c4c7b752a2 100644 --- a/tools/testing/selftests/ftrace/test.d/functions +++ b/tools/testing/selftests/ftrace/test.d/functions @@ -37,17 +37,18 @@ reset_ftrace_filter() { # reset all triggers in set_ftrace_filter if [ "$tr" = "" ]; then continue fi + name=`echo $t | cut -d: -f1 | cut -d' ' -f1` if [ $tr = "enable_event" -o $tr = "disable_event" ]; then - tr=`echo $t | cut -d: -f1-4` + tr=`echo $t | cut -d: -f2-4` limit=`echo $t | cut -d: -f5` else - tr=`echo $t | cut -d: -f1-2` + tr=`echo $t | cut -d: -f2` limit=`echo $t | cut -d: -f3` fi if [ "$limit" != "unlimited" ]; then tr="$tr:$limit" fi - echo "!$tr" > set_ftrace_filter + echo "!$name:$tr" > set_ftrace_filter done } From 0787ce336075ac0fa2d356de4e3c2a2488e851a6 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 6 Feb 2018 17:15:02 -0500 Subject: [PATCH 4/6] selftests/ftrace: Have reset_ftrace_filter handle multiple instances If a probe is attached to a static function that is in multiple files with the same name, removing it by name will remove all instances: # grep jump_label_unlock set_ftrace_filter jump_label_unlock:traceoff:unlimited jump_label_unlock:traceoff:unlimited # echo '!jump_label_unlock:traceoff' >> set_ftrace_filter # grep jump_label_unlock set_ftrace_filter # But the loop in reset_ftrace_filter will try to remove multiple instances multiple times. If this happens the second time will error and cause the test to fail. At each iteration of the loop, check to see if the probe being removed still exists. Cc: Shuah Khan Signed-off-by: Steven Rostedt (VMware) --- tools/testing/selftests/ftrace/test.d/functions | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions index e7c4c7b752a2..df3dd7fe5f9b 100644 --- a/tools/testing/selftests/ftrace/test.d/functions +++ b/tools/testing/selftests/ftrace/test.d/functions @@ -37,6 +37,9 @@ reset_ftrace_filter() { # reset all triggers in set_ftrace_filter if [ "$tr" = "" ]; then continue fi + if ! grep -q "$t" set_ftrace_filter; then + continue; + fi name=`echo $t | cut -d: -f1 | cut -d' ' -f1` if [ $tr = "enable_event" -o $tr = "disable_event" ]; then tr=`echo $t | cut -d: -f2-4` From 97fe22adf33f06519bfdf7dad33bcd562e366c8f Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 6 Feb 2018 17:19:03 -0500 Subject: [PATCH 5/6] selftests/ftrace: Add some missing glob checks Al Viro discovered a bug in the glob ftrace filtering code where "*a*b" is treated the same as "a*b", and functions that would be selected by "*a*b" but not "a*b" are not selected with "*a*b". Add tests for patterns "*a*b" and "a*b*" to the glob selftest. Link: http://lkml.kernel.org/r/20180127170748.GF13338@ZenIV.linux.org.uk Cc: Shuah Khan Acked-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- .../selftests/ftrace/test.d/ftrace/func-filter-glob.tc | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-glob.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-glob.tc index 589d52b211b7..27a54a17da65 100644 --- a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-glob.tc +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-glob.tc @@ -29,6 +29,12 @@ ftrace_filter_check '*schedule*' '^.*schedule.*$' # filter by *, end match ftrace_filter_check 'schedule*' '^schedule.*$' +# filter by *mid*end +ftrace_filter_check '*aw*lock' '.*aw.*lock$' + +# filter by start*mid* +ftrace_filter_check 'mutex*try*' '^mutex.*try.*' + # Advanced full-glob matching feature is recently supported. # Skip the tests if we are sure the kernel does not support it. if grep -q 'accepts: .* glob-matching-pattern' README ; then From 878cb3fb06c67e8f1a452346e0bc6bb85f29b0a0 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 6 Feb 2018 17:28:36 -0500 Subject: [PATCH 6/6] selftests/ftrace: Add more tests for removing of function probes Al Viro discovered a bug in the removing of function probes where if it had a '*' at the beginning, it would fail to find any matches. That is, because it reset the glob search string to the the initial string with a "MATCH_END" type, instead of skipping the wildcard "*" it included it, where it would not match any functions because "*" was being treated as a normal character and not a wildcard one. Link: http://lkml.kernel.org/r/20180127031706.GE13338@ZenIV.linux.org.uk Cc: Shuah Khan Signed-off-by: Steven Rostedt (VMware) --- .../test.d/ftrace/func_set_ftrace_file.tc | 37 +++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc index 0f3f92622e33..68e7a48f5828 100644 --- a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc @@ -128,6 +128,43 @@ if check_set_ftrace_filter "$FUNC1" "$FUNC2" ; then fail "Expected $FUNC1 and $FUNC2" fi +test_actual() { # Compares $TMPDIR/expected with set_ftrace_filter + cat set_ftrace_filter | grep -v '#' | cut -d' ' -f1 | cut -d':' -f1 | sort -u > $TMPDIR/actual + DIFF=`diff $TMPDIR/actual $TMPDIR/expected` + test -z "$DIFF" +} + +# Set traceoff trigger for all fuctions with "lock" in their name +cat available_filter_functions | cut -d' ' -f1 | grep 'lock' | sort -u > $TMPDIR/expected +echo '*lock*:traceoff' > set_ftrace_filter +test_actual + +# now remove all with 'try' in it, and end with lock +grep -v 'try.*lock$' $TMPDIR/expected > $TMPDIR/expected2 +mv $TMPDIR/expected2 $TMPDIR/expected +echo '!*try*lock:traceoff' >> set_ftrace_filter +test_actual + +# remove all that start with "m" and end with "lock" +grep -v '^m.*lock$' $TMPDIR/expected > $TMPDIR/expected2 +mv $TMPDIR/expected2 $TMPDIR/expected +echo '!m*lock:traceoff' >> set_ftrace_filter +test_actual + +# remove all that start with "c" and have "unlock" +grep -v '^c.*unlock' $TMPDIR/expected > $TMPDIR/expected2 +mv $TMPDIR/expected2 $TMPDIR/expected +echo '!c*unlock*:traceoff' >> set_ftrace_filter +test_actual + +# clear all the rest +> $TMPDIR/expected +echo '!*:traceoff' >> set_ftrace_filter +test_actual + +rm $TMPDIR/expected +rm $TMPDIR/actual + do_reset exit 0