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Date:   Fri, 9 Jul 2021 09:22:56 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Baokun Li <libaokun1@huawei.com>,
        Tom Zanussi <zanussi@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>
Subject: [GIT PULL] tracing: Fix for histogram and clean up in ftrace
Message-ID: <20210709092256.567f77a1@oasis.local.home>
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Linus,

Tracing fix for histograms and a clean up in ftrace

 - Fixed a bug that broke the .sym-offset modifier and added a test to make
   sure nothing breaks it again.

 - Replace a list_del/list_add() with a list_move()


Please pull the latest trace-v5.14-2 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v5.14-2

Tag SHA1: 153d0ceb33c062166324b79cde4ab67e534a0678
Head SHA1: 3ecda64475bccdfdcbfd5b9b7e4bf639d8b233da


Baokun Li (1):
      ftrace: Use list_move instead of list_del/list_add

Steven Rostedt (VMware) (2):
      tracing/histograms: Fix parsing of "sym-offset" modifier
      tracing/selftests: Add tests to test histogram sym and sym-offset modifiers

----
 kernel/trace/ftrace.c                                  |  3 +--
 kernel/trace/trace_events_hist.c                       |  7 +++++++
 .../selftests/ftrace/test.d/trigger/trigger-hist.tc    | 18 ++++++++++++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)
---------------------------
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 72ef4dccbcc4..e6fb3e6e1ffc 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4212,8 +4212,7 @@ static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
 		if (!func) /* warn? */
 			continue;
 
-		list_del(&ftrace_mod->list);
-		list_add(&ftrace_mod->list, &process_mods);
+		list_move(&ftrace_mod->list, &process_mods);
 
 		/* Use the newly allocated func, as it may be "*" */
 		kfree(ftrace_mod->func);
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index ba03b7d84fc2..0207aeed31e6 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1555,6 +1555,13 @@ static int contains_operator(char *str)
 
 	switch (*op) {
 	case '-':
+		/*
+		 * Unfortunately, the modifier ".sym-offset"
+		 * can confuse things.
+		 */
+		if (op - str >= 4 && !strncmp(op - 4, ".sym-offset", 11))
+			return FIELD_OP_NONE;
+
 		if (*str == '-')
 			field_op = FIELD_OP_UNARY_MINUS;
 		else
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc
index 2950bfbc6fce..adae72665500 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc
@@ -39,6 +39,24 @@ grep "parent_comm: $COMM" events/sched/sched_process_fork/hist > /dev/null || \
 
 reset_trigger
 
+echo "Test histogram with sym modifier"
+
+echo 'hist:keys=call_site.sym' > events/kmem/kmalloc/trigger
+for i in `seq 1 10` ; do ( echo "forked" > /dev/null); done
+grep '{ call_site: \[[0-9a-f][0-9a-f]*\] [_a-zA-Z][_a-zA-Z]* *}' events/kmem/kmalloc/hist > /dev/null || \
+    fail "sym modifier on kmalloc call_site did not work"
+
+reset_trigger
+
+echo "Test histogram with sym-offset modifier"
+
+echo 'hist:keys=call_site.sym-offset' > events/kmem/kmalloc/trigger
+for i in `seq 1 10` ; do ( echo "forked" > /dev/null); done
+grep '{ call_site: \[[0-9a-f][0-9a-f]*\] [_a-zA-Z][_a-zA-Z]*+0x[0-9a-f][0-9a-f]*' events/kmem/kmalloc/hist > /dev/null || \
+    fail "sym-offset modifier on kmalloc call_site did not work"
+
+reset_trigger
+
 echo "Test histogram with sort key"
 
 echo 'hist:keys=parent_pid,child_pid:sort=child_pid.ascending' > events/sched/sched_process_fork/trigger