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authorLinus Torvalds <torvalds@linux-foundation.org>2016-05-22 19:40:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-22 19:40:39 -0700
commit7639dad93a5564579987abded4ec05e3db13659d (patch)
treed786a45e79672ee3ea04e93d60ec1da02cb17940
parent77ed402b7f53cbe50ae8384a172a5b9713020400 (diff)
parent8329e818f14926a6040df86b2668568bde342ebf (diff)
Merge tag 'trace-v4.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull motr tracing updates from Steven Rostedt: "Three more changes. - I forgot that I had another selftest to stress test the ftrace instance creation. It was actually suppose to go into the 4.6 merge window, but I never committed it. I almost forgot about it again, but noticed it was missing from your tree. - Soumya PN sent me a clean up patch to not disable interrupts when taking the tasklist_lock for read, as it's unnecessary because that lock is never taken for write in irq context. - Newer gcc's can cause the jump in the function_graph code to the global ftrace_stub label to be a short jump instead of a long one. As that jump is dynamically converted to jump to the trace code to do function graph tracing, and that conversion expects a long jump it can corrupt the ftrace_stub itself (it's directly after that call). One way to prevent gcc from using a short jump is to declare the ftrace_stub as a weak function, which we do here to keep gcc from optimizing too much" * tag 'trace-v4.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace/x86: Set ftrace_stub to weak to prevent gcc from using short jumps to it ftrace: Don't disable irqs when taking the tasklist_lock read_lock ftracetest: Add instance created, delete, read and enable event test
-rw-r--r--arch/x86/kernel/mcount_64.S3
-rw-r--r--kernel/trace/ftrace.c5
-rw-r--r--tools/testing/selftests/ftrace/test.d/instances/instance-event.tc143
3 files changed, 147 insertions, 4 deletions
diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S
index ed48a9f465f8..61924222a9e1 100644
--- a/arch/x86/kernel/mcount_64.S
+++ b/arch/x86/kernel/mcount_64.S
@@ -182,7 +182,8 @@ GLOBAL(ftrace_graph_call)
jmp ftrace_stub
#endif
-GLOBAL(ftrace_stub)
+/* This is weak to keep gas from relaxing the jumps */
+WEAK(ftrace_stub)
retq
END(ftrace_caller)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index a6c8252d7776..900dbb1efff2 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5737,7 +5737,6 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
{
int i;
int ret = 0;
- unsigned long flags;
int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
struct task_struct *g, *t;
@@ -5753,7 +5752,7 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
}
}
- read_lock_irqsave(&tasklist_lock, flags);
+ read_lock(&tasklist_lock);
do_each_thread(g, t) {
if (start == end) {
ret = -EAGAIN;
@@ -5771,7 +5770,7 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
} while_each_thread(g, t);
unlock:
- read_unlock_irqrestore(&tasklist_lock, flags);
+ read_unlock(&tasklist_lock);
free:
for (i = start; i < end; i++)
kfree(ret_stack_list[i]);
diff --git a/tools/testing/selftests/ftrace/test.d/instances/instance-event.tc b/tools/testing/selftests/ftrace/test.d/instances/instance-event.tc
new file mode 100644
index 000000000000..5f2abd03f16b
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/instances/instance-event.tc
@@ -0,0 +1,143 @@
+#!/bin/sh
+# description: Test creation and deletion of trace instances while setting an event
+
+if [ ! -d instances ] ; then
+ echo "no instance directory with this kernel"
+ exit_unsupported;
+fi
+
+fail() { # mesg
+ rmdir foo 2>/dev/null
+ echo $1
+ set -e
+ exit $FAIL
+}
+
+cd instances
+
+# we don't want to fail on error
+set +e
+
+mkdir x
+rmdir x
+result=$?
+
+if [ $result -ne 0 ]; then
+ echo "instance rmdir not supported"
+ exit_unsupported
+fi
+
+instance_slam() {
+ while :; do
+ mkdir foo 2> /dev/null
+ rmdir foo 2> /dev/null
+ done
+}
+
+instance_read() {
+ while :; do
+ cat foo/trace 1> /dev/null 2>&1
+ done
+}
+
+instance_set() {
+ while :; do
+ echo 1 > foo/events/sched/sched_switch
+ done 2> /dev/null
+}
+
+instance_slam &
+p1=$!
+echo $p1
+
+instance_set &
+p2=$!
+echo $p2
+
+instance_read &
+p3=$!
+echo $p3
+
+sleep 1
+
+kill -1 $p3
+kill -1 $p2
+kill -1 $p1
+
+echo "Wait for processes to finish"
+wait $p1 $p2 $p3
+echo "all processes finished, wait for cleanup"
+sleep 1
+
+mkdir foo
+ls foo > /dev/null
+rmdir foo
+if [ -d foo ]; then
+ fail "foo still exists"
+fi
+exit 0
+
+
+
+
+instance_slam() {
+ while :; do
+ mkdir x
+ mkdir y
+ mkdir z
+ rmdir x
+ rmdir y
+ rmdir z
+ done 2>/dev/null
+}
+
+instance_slam &
+x=`jobs -l`
+p1=`echo $x | cut -d' ' -f2`
+echo $p1
+
+instance_slam &
+x=`jobs -l | tail -1`
+p2=`echo $x | cut -d' ' -f2`
+echo $p2
+
+instance_slam &
+x=`jobs -l | tail -1`
+p3=`echo $x | cut -d' ' -f2`
+echo $p3
+
+instance_slam &
+x=`jobs -l | tail -1`
+p4=`echo $x | cut -d' ' -f2`
+echo $p4
+
+instance_slam &
+x=`jobs -l | tail -1`
+p5=`echo $x | cut -d' ' -f2`
+echo $p5
+
+ls -lR >/dev/null
+sleep 1
+
+kill -1 $p1
+kill -1 $p2
+kill -1 $p3
+kill -1 $p4
+kill -1 $p5
+
+echo "Wait for processes to finish"
+wait $p1 $p2 $p3 $p4 $p5
+echo "all processes finished, wait for cleanup"
+
+mkdir x y z
+ls x y z
+rmdir x y z
+for d in x y z; do
+ if [ -d $d ]; then
+ fail "instance $d still exists"
+ fi
+done
+
+set -e
+
+exit 0