[GIT PULL] tracing: Minor fixes and clean ups for 5.19

From: Steven Rostedt
Date: Thu Jun 23 2022 - 14:22:08 EST




Linus,

Tracing fixes:

- Check for NULL in kretprobe_dispatcher()
NULL can now be passed in, make sure it can handle it

- Clean up unneeded #endif #ifdef of the same preprocessor check in the
middle of the block.

- Comment clean up

- Remove unneeded initialization of the "ret" variable in
__trace_uprobe_create()


Please pull the latest trace-v5.19-rc1 tree, which can be found at:


git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v5.19-rc1

Tag SHA1: 552669fd41f0f967ea7abb1e1b9138280b916208
Head SHA1: 12c3e0c92fd7cb3d3b698d84fdde7dccb6ba8822


Gautam Menghani (1):
tracing/uprobes: Remove unwanted initialization in __trace_uprobe_create()

Masami Hiramatsu (Google) (1):
tracing/kprobes: Check whether get_kretprobe() returns NULL in kretprobe_dispatcher()

Xiang wangx (1):
tracefs: Fix syntax errors in comments

sunliming (1):
tracing: Simplify conditional compilation code in tracing_set_tracer()

----
fs/tracefs/inode.c | 2 +-
kernel/trace/trace.c | 2 --
kernel/trace/trace_kprobe.c | 11 ++++++++++-
kernel/trace/trace_uprobe.c | 1 -
4 files changed, 11 insertions(+), 5 deletions(-)
---------------------------
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index de7252715b12..81d26abf486f 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -553,7 +553,7 @@ struct dentry *tracefs_create_dir(const char *name, struct dentry *parent)
*
* Only one instances directory is allowed.
*
- * The instances directory is special as it allows for mkdir and rmdir to
+ * The instances directory is special as it allows for mkdir and rmdir
* to be done by userspace. When a mkdir or rmdir is performed, the inode
* locks are released and the methods passed in (@mkdir and @rmdir) are
* called without locks and with the name of the directory being created
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2c95992e2c71..a8cfac0611bc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6424,9 +6424,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
synchronize_rcu();
free_snapshot(tr);
}
-#endif

-#ifdef CONFIG_TRACER_MAX_TRACE
if (t->use_max_tr && !had_max_tr) {
ret = tracing_alloc_snapshot_instance(tr);
if (ret < 0)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 93507330462c..a245ea673715 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1718,8 +1718,17 @@ static int
kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
{
struct kretprobe *rp = get_kretprobe(ri);
- struct trace_kprobe *tk = container_of(rp, struct trace_kprobe, rp);
+ struct trace_kprobe *tk;
+
+ /*
+ * There is a small chance that get_kretprobe(ri) returns NULL when
+ * the kretprobe is unregister on another CPU between kretprobe's
+ * trampoline_handler and this function.
+ */
+ if (unlikely(!rp))
+ return 0;

+ tk = container_of(rp, struct trace_kprobe, rp);
raw_cpu_inc(*tk->nhit);

if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 9711589273cd..c3dc4f859a6b 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -546,7 +546,6 @@ static int __trace_uprobe_create(int argc, const char **argv)
bool is_return = false;
int i, ret;

- ret = 0;
ref_ctr_offset = 0;

switch (argv[0][0]) {