From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
"Joel Fernandes (Google)" <joel@joelfernandes.org>
Subject: [for-next][PATCH 26/34] trace: Use rcu_dereference_raw for hooks from trace-event subsystem
Date: Sat, 11 Aug 2018 09:49:54 -0400 [thread overview]
Message-ID: <20180811135015.738126021@goodmis.org> (raw)
In-Reply-To: 20180811134928.034373761@goodmis.org
From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Since we switched to using SRCU for tracepoints used in the idle path,
we can no longer use rcu_dereference_sched for dereferencing points in
trace-event hooks.
Since tracepoints can now use either SRCU or sched-RCU, just use
rcu_dereference_raw for traceevents just like we're doing when
dereferencing the tracepoint table.
This prevents an RCU warning reported by Masami:
[ 282.060593] WARNING: can't dereference registers at 00000000f3c7f62b
[ 282.063200] =============================
[ 282.064082] WARNING: suspicious RCU usage
[ 282.064963] 4.18.0-rc6+ #15 Tainted: G W
[ 282.066048] -----------------------------
[ 282.066923] /home/mhiramat/ksrc/linux/kernel/trace/trace_events.c:242
suspicious rcu_dereference_check() usage!
[ 282.068974]
[ 282.068974] other info that might help us debug this:
[ 282.068974]
[ 282.070770]
[ 282.070770] RCU used illegally from idle CPU!
[ 282.070770] rcu_scheduler_active = 2, debug_locks = 1
[ 282.072938] RCU used illegally from extended quiescent state!
[ 282.074183] no locks held by swapper/0/0.
[ 282.075071]
[ 282.075071] stack backtrace:
[ 282.076121] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W
[ 282.077782] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
[ 282.079604] Call Trace:
[ 282.080212] <IRQ>
[ 282.080755] dump_stack+0x85/0xcb
[ 282.081523] trace_event_ignore_this_pid+0x66/0x70
[ 282.082541] trace_event_raw_event_preemptirq_template+0xa2/0xb0
[ 282.083774] ? interrupt_entry+0xc4/0xe0
[ 282.084665] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 282.085669] trace_hardirqs_off_caller+0x90/0xd0
[ 282.086597] trace_hardirqs_off_thunk+0x1a/0x1c
[ 282.087433] ? call_function_interrupt+0xa/0x20
[ 282.088201] interrupt_entry+0xc4/0xe0
[ 282.088848] ? call_function_interrupt+0xa/0x20
[ 282.089579] </IRQ>
[ 282.090029] ? native_safe_halt+0x2/0x10
[ 282.090695] ? default_idle+0x1f/0x160
[ 282.091330] ? default_idle_call+0x24/0x40
[ 282.091997] ? do_idle+0x210/0x250
[ 282.092658] ? cpu_startup_entry+0x6f/0x80
[ 282.093338] ? start_kernel+0x49d/0x4bd
[ 282.093987] ? secondary_startup_64+0xa5/0xb0
Link: http://lkml.kernel.org/r/20180803023407.225852-1-joel@joelfernandes.org
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: e6753f23d961 ("tracepoint: Make rcuidle tracepoint callers use SRCU")
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_events.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 14ff4ff3caab..7b508ce8ac44 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -239,7 +239,7 @@ bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
struct trace_array_cpu *data;
struct trace_pid_list *pid_list;
- pid_list = rcu_dereference_sched(tr->filtered_pids);
+ pid_list = rcu_dereference_raw(tr->filtered_pids);
if (!pid_list)
return false;
@@ -512,7 +512,7 @@ event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
struct trace_pid_list *pid_list;
struct trace_array *tr = data;
- pid_list = rcu_dereference_sched(tr->filtered_pids);
+ pid_list = rcu_dereference_raw(tr->filtered_pids);
trace_filter_add_remove_task(pid_list, NULL, task);
}
--
2.18.0
next prev parent reply other threads:[~2018-08-11 13:50 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-11 13:49 [for-next][PATCH 00/34] tracing: My official queue finally passed testing and ready for linux-next Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 01/34] srcu: Add notrace variants of srcu_read_{lock,unlock} Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 02/34] srcu: Add notrace variant of srcu_dereference Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 03/34] tracing/irqsoff: Split reset into separate functions Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 04/34] lib: Add module for testing preemptoff/irqsoff latency tracers Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 05/34] kselftests: Add tests for the preemptoff and irqsoff tracers Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 06/34] tracing: Make unregister_trigger() static Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 07/34] tracing: Remove orphaned function using_ftrace_ops_list_func() Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 08/34] tracing: Remove orphaned function ftrace_nr_registered_ops() Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 09/34] tracing/kprobes: Simplify the logic of enable_trace_kprobe() Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 10/34] tracing: preemptirq_delay_run() can be static Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 11/34] tracing: kprobes: Prohibit probing on notrace function Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 12/34] selftest/ftrace: Move kprobe selftest function to separate compile unit Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 13/34] selftests/ftrace: Fix kprobe string testcase to not probe notrace function Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 14/34] lockdep: Use this_cpu_ptr instead of get_cpu_var stats Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 15/34] tracepoint: Make rcuidle tracepoint callers use SRCU Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 16/34] tracing: Centralize preemptirq tracepoints and unify their usage Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 17/34] tracefs: Annotate tracefs_ops with __ro_after_init Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 18/34] tracing: Do not call start/stop() functions when tracing_on does not change Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 19/34] ftrace: Add missing check for existing hwlat thread Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 20/34] tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 21/34] tracing: Make tracer_tracing_is_on() return bool Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 22/34] ring-buffer: Make ring_buffer_record_is_on() " Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 23/34] ring-buffer: Make ring_buffer_record_is_set_on() " Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 24/34] ftrace: Use true and false for boolean values in ops_references_rec() Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 25/34] tracing/kprobes: Fix within_notrace_func() to check only notrace functions Steven Rostedt
2018-08-11 13:49 ` Steven Rostedt [this message]
2018-08-11 13:49 ` [for-next][PATCH 27/34] tracing: irqsoff: Account for additional preempt_disable Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 28/34] tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage" Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 29/34] tracing/irqsoff: Handle preempt_count for different configs Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 30/34] tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage" Steven Rostedt
2018-08-11 13:49 ` [for-next][PATCH 31/34] ftrace: Remove unused pointer ftrace_swapper_pid Steven Rostedt
2018-08-11 13:50 ` [for-next][PATCH 32/34] tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister() Steven Rostedt
2018-08-11 13:50 ` [for-next][PATCH 33/34] uprobes: Use synchronize_rcu() not synchronize_sched() Steven Rostedt
2018-08-11 13:50 ` [for-next][PATCH 34/34] tracepoints: Free early tracepoints after RCU is initialized Steven Rostedt
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