From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
stable@vger.kernel.org,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.ibm.com>,
syzbot+774fddf07b7ab29a1e55@syzkaller.appspotmail.com,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: [for-next][PATCH 03/21] tracing: Fix sched switch start/stop refcount racy updates
Date: Thu, 30 Jan 2020 09:47:46 -0500 [thread overview]
Message-ID: <20200130144810.669688514@goodmis.org> (raw)
In-Reply-To: 20200130144743.527378179@goodmis.org
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reading the sched_cmdline_ref and sched_tgid_ref initial state within
tracing_start_sched_switch without holding the sched_register_mutex is
racy against concurrent updates, which can lead to tracepoint probes
being registered more than once (and thus trigger warnings within
tracepoint.c).
[ May be the fix for this bug ]
Link: https://lore.kernel.org/r/000000000000ab6f84056c786b93@google.com
Link: http://lkml.kernel.org/r/20190817141208.15226-1-mathieu.desnoyers@efficios.com
Cc: stable@vger.kernel.org
CC: Steven Rostedt (VMware) <rostedt@goodmis.org>
CC: Joel Fernandes (Google) <joel@joelfernandes.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul E. McKenney <paulmck@linux.ibm.com>
Reported-by: syzbot+774fddf07b7ab29a1e55@syzkaller.appspotmail.com
Fixes: d914ba37d7145 ("tracing: Add support for recording tgid of tasks")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_sched_switch.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index e288168661e1..e304196d7c28 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -89,8 +89,10 @@ static void tracing_sched_unregister(void)
static void tracing_start_sched_switch(int ops)
{
- bool sched_register = (!sched_cmdline_ref && !sched_tgid_ref);
+ bool sched_register;
+
mutex_lock(&sched_register_mutex);
+ sched_register = (!sched_cmdline_ref && !sched_tgid_ref);
switch (ops) {
case RECORD_CMDLINE:
--
2.24.1
next prev parent reply other threads:[~2020-01-30 14:48 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-30 14:47 [for-next][PATCH 00/21] tracing: Some more last minute updates for 5.6 Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 01/21] tracing/boot: Include required headers and sort it alphabetically Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 02/21] tracing/boot: Move external function declarations to kernel/trace/trace.h Steven Rostedt
2020-01-30 14:47 ` Steven Rostedt [this message]
2020-01-30 14:47 ` [for-next][PATCH 04/21] ftrace: fpid_next() should increase position index Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 05/21] tracing: eval_map_next() should always " Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 06/21] trigger_next should " Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 07/21] tracing: Add trace_array_find/_get() to find instance trace arrays Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 08/21] tracing: Add trace_get/put_event_file() Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 09/21] tracing: Add synth_event_delete() Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 10/21] tracing: Add dynamic event command creation interface Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 11/21] tracing: Add synthetic event command generation functions Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 12/21] tracing: Add synth_event_trace() and related functions Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 13/21] tracing: Add synth event generation test module Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 14/21] tracing: Add kprobe event command generation functions Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 15/21] tracing: Change trace_boot to use kprobe_event interface Steven Rostedt
2020-01-30 14:47 ` [for-next][PATCH 16/21] tracing: Add kprobe event command generation test module Steven Rostedt
2020-01-30 14:48 ` [for-next][PATCH 17/21] tracing: Documentation for in-kernel synthetic event API Steven Rostedt
2020-01-30 14:48 ` [for-next][PATCH 18/21] tracing: Move all function tracing configs together Steven Rostedt
2020-01-30 14:48 ` [for-next][PATCH 19/21] tracing: Move tracing test module " Steven Rostedt
2020-01-30 14:48 ` [for-next][PATCH 20/21] tracing: Move mmio tracer config up with the other tracers Steven Rostedt
2020-01-30 14:48 ` [for-next][PATCH 21/21] tracing: Move tracing selftests to bottom of menu Steven Rostedt
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