[for-linus][PATCH 0/3] tracing: Last three patches (hopefully) before my pull request

[for-linus][PATCH 0/3] tracing: Last three patches (hopefully) before my pull request

[Steven Rostedt]

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: 37f9e8b51dbe7f69d9f80aec98f1514f0cd4085e


Masami Hiramatsu (1):
      bootconfig: Fix to find the initargs correctly

Muchun Song (1):
      kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE

Steven Rostedt (VMware) (1):
      tracing: Use trace_sched_process_free() instead of exit() for pid tracing

----
 init/main.c                 | 14 ++++++++------
 kernel/kprobes.c            | 17 ++++++++++++++---
 kernel/trace/ftrace.c       |  4 ++--
 kernel/trace/trace_events.c |  4 ++--
 4 files changed, 26 insertions(+), 13 deletions(-)

[for-linus][PATCH 1/3] bootconfig: Fix to find the initargs correctly

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Since the parse_args() stops parsing at '--', bootconfig_params()
will never get the '--' as param and initargs_found never be true.
In the result, if we pass some init arguments via the bootconfig,
those are always appended to the kernel command line with '--'
even if the kernel command line already has '--'.

To fix this correctly, check the return value of parse_args()
and set initargs_found true if the return value is not an error
but a valid address.

Link: https://lkml.kernel.org/r/159650953285.270383.14822353843556363851.stgit@devnote2

Fixes: f61872bb58a1 ("bootconfig: Use parse_args() to find bootconfig and '--'")
Cc: stable@vger.kernel.org
Reported-by: Arvind Sankar <nivedita@alum.mit.edu>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 init/main.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/init/main.c b/init/main.c
index 0ead83e86b5a..883ded3638e5 100644
--- a/init/main.c
+++ b/init/main.c
@@ -387,8 +387,6 @@ static int __init bootconfig_params(char *param, char *val,
 {
 	if (strcmp(param, "bootconfig") == 0) {
 		bootconfig_found = true;
-	} else if (strcmp(param, "--") == 0) {
-		initargs_found = true;
 	}
 	return 0;
 }
@@ -399,19 +397,23 @@ static void __init setup_boot_config(const char *cmdline)
 	const char *msg;
 	int pos;
 	u32 size, csum;
-	char *data, *copy;
+	char *data, *copy, *err;
 	int ret;
 
 	/* Cut out the bootconfig data even if we have no bootconfig option */
 	data = get_boot_config_from_initrd(&size, &csum);
 
 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
-	parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
-		   bootconfig_params);
+	err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
+			 bootconfig_params);
 
-	if (!bootconfig_found)
+	if (IS_ERR(err) || !bootconfig_found)
 		return;
 
+	/* parse_args() stops at '--' and returns an address */
+	if (err)
+		initargs_found = true;
+
 	if (!data) {
 		pr_err("'bootconfig' found on command line, but no bootconfig found\n");
 		return;
-- 
2.26.2

[for-linus][PATCH 2/3] tracing: Use trace_sched_process_free() instead of exit() for pid tracing

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

On exit, if a process is preempted after the trace_sched_process_exit()
tracepoint but before the process is done exiting, then when it gets
scheduled in, the function tracers will not filter it properly against the
function tracing pid filters.

That is because the function tracing pid filters hooks to the
sched_process_exit() tracepoint to remove the exiting task's pid from the
filter list. Because the filtering happens at the sched_switch tracepoint,
when the exiting task schedules back in to finish up the exit, it will no
longer be in the function pid filtering tables.

This was noticeable in the notrace self tests on a preemptable kernel, as
the tests would fail as it exits and preempted after being taken off the
notrace filter table and on scheduling back in it would not be in the
notrace list, and then the ending of the exit function would trace. The test
detected this and would fail.

Cc: stable@vger.kernel.org
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 1e10486ffee0a ("ftrace: Add 'function-fork' trace option")
Fixes: c37775d57830a ("tracing: Add infrastructure to allow set_event_pid to follow children"
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c       | 4 ++--
 kernel/trace/trace_events.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4e3a5d79c078..76f2dd6fd414 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6985,12 +6985,12 @@ void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
 	if (enable) {
 		register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
 						  tr);
-		register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
+		register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
 						  tr);
 	} else {
 		unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
 						    tr);
-		unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
+		unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
 						    tr);
 	}
 }
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f6f55682d3e2..a85effb2373b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -538,12 +538,12 @@ void trace_event_follow_fork(struct trace_array *tr, bool enable)
 	if (enable) {
 		register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
 						       tr, INT_MIN);
-		register_trace_prio_sched_process_exit(event_filter_pid_sched_process_exit,
+		register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
 						       tr, INT_MAX);
 	} else {
 		unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
 						    tr);
-		unregister_trace_sched_process_exit(event_filter_pid_sched_process_exit,
+		unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
 						    tr);
 	}
 }
-- 
2.26.2

[for-linus][PATCH 3/3] kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE

[Steven Rostedt]

From: Muchun Song <songmuchun@bytedance.com>

Fix compiler warning(as show below) for !CONFIG_KPROBES_ON_FTRACE.

kernel/kprobes.c: In function 'kill_kprobe':
kernel/kprobes.c:1116:33: warning: statement with no effect
[-Wunused-value]
 1116 | #define disarm_kprobe_ftrace(p) (-ENODEV)
      |                                 ^
kernel/kprobes.c:2154:3: note: in expansion of macro
'disarm_kprobe_ftrace'
 2154 |   disarm_kprobe_ftrace(p);

Link: https://lore.kernel.org/r/20200805142136.0331f7ea@canb.auug.org.au
Link: https://lkml.kernel.org/r/20200805172046.19066-1-songmuchun@bytedance.com

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/kprobes.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 07bf03fcf574..66d14107968d 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1079,9 +1079,20 @@ static int disarm_kprobe_ftrace(struct kprobe *p)
 		ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
 }
 #else	/* !CONFIG_KPROBES_ON_FTRACE */
-#define prepare_kprobe(p)	arch_prepare_kprobe(p)
-#define arm_kprobe_ftrace(p)	(-ENODEV)
-#define disarm_kprobe_ftrace(p)	(-ENODEV)
+static inline int prepare_kprobe(struct kprobe *p)
+{
+	return arch_prepare_kprobe(p);
+}
+
+static inline int arm_kprobe_ftrace(struct kprobe *p)
+{
+	return -ENODEV;
+}
+
+static inline int disarm_kprobe_ftrace(struct kprobe *p)
+{
+	return -ENODEV;
+}
 #endif
 
 /* Arm a kprobe with text_mutex */
-- 
2.26.2