From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Tom Zanussi <zanussi@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [for-next][PATCH 26/26] tracing: trigger: Replace unneeded RCU-list traversals
Date: Tue, 14 Jan 2020 17:11:31 -0500 [thread overview]
Message-ID: <20200114171131.04eff860@gandalf.local.home> (raw)
In-Reply-To: <20200114210339.492724604@goodmis.org>
On Tue, 14 Jan 2020 16:03:42 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> From: Masami Hiramatsu <mhiramat@kernel.org>
>
> With CONFIG_PROVE_RCU_LIST, I had many suspicious RCU warnings
> when I ran ftracetest trigger testcases.
>
> -----
> # dmesg -c > /dev/null
> # ./ftracetest test.d/trigger
> ...
> # dmesg | grep "RCU-list traversed" | cut -f 2 -d ] | cut -f 2 -d " "
> kernel/trace/trace_events_hist.c:6070
> kernel/trace/trace_events_hist.c:1760
> kernel/trace/trace_events_hist.c:5911
> kernel/trace/trace_events_trigger.c:504
> kernel/trace/trace_events_hist.c:1810
> kernel/trace/trace_events_hist.c:3158
> kernel/trace/trace_events_hist.c:3105
> kernel/trace/trace_events_hist.c:5518
> kernel/trace/trace_events_hist.c:5998
> kernel/trace/trace_events_hist.c:6019
> kernel/trace/trace_events_hist.c:6044
> kernel/trace/trace_events_trigger.c:1500
> kernel/trace/trace_events_trigger.c:1540
> kernel/trace/trace_events_trigger.c:539
> kernel/trace/trace_events_trigger.c:584
> -----
>
> I investigated those warnings and found that the RCU-list
> traversals in event trigger and hist didn't need to use
> RCU version because those were called only under event_mutex.
>
> I also checked other RCU-list traversals related to event
> trigger list, and found that most of them were called from
> event_hist_trigger_func() or hist_unregister_trigger() or
> register/unregister functions except for a few cases.
>
> Replace these unneeded RCU-list traversals with normal list
> traversal macro and lockdep_assert_held() to check the
> event_mutex is held.
>
> Link: http://lkml.kernel.org/r/157680910305.11685.15110237954275915782.stgit@devnote2
>
> Reviewed-by: Tom Zanussi <zanussi@kernel.org>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
> kernel/trace/trace_events_hist.c | 41 +++++++++++++++++++++--------
> kernel/trace/trace_events_trigger.c | 20 ++++++++++----
> 2 files changed, 45 insertions(+), 16 deletions(-)
>
I think I may add this to my urgent branch and mark this for stable.
-- Steve
prev parent reply other threads:[~2020-01-14 22:11 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 21:03 [for-next][PATCH 00/26] tracing: Updates for 5.6 Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 01/26] perf: Make struct ring_buffer less ambiguous Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 02/26] tracing: Rename trace_buffer to array_buffer Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 03/26] tracing: Make struct ring_buffer less ambiguous Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 04/26] bootconfig: Add Extra Boot Config support Steven Rostedt
2020-02-06 11:54 ` Borislav Petkov
2020-02-06 14:41 ` Masami Hiramatsu
2020-02-06 17:20 ` Geert Uytterhoeven
2020-02-07 0:30 ` Masami Hiramatsu
2020-02-07 8:49 ` Geert Uytterhoeven
2020-02-07 13:17 ` Masami Hiramatsu
2020-02-07 14:28 ` [PATCH] bootconfig: Allocate xbc_nodes array dynamically Masami Hiramatsu
2020-02-06 17:58 ` [for-next][PATCH 04/26] bootconfig: Add Extra Boot Config support Borislav Petkov
2020-02-06 18:10 ` Randy Dunlap
2020-02-06 22:39 ` Steven Rostedt
2020-02-06 22:51 ` Borislav Petkov
2020-02-07 8:59 ` Geert Uytterhoeven
2020-02-07 2:46 ` Masami Hiramatsu
2020-02-07 11:41 ` Borislav Petkov
2020-02-07 15:06 ` Masami Hiramatsu
2020-02-10 11:25 ` Borislav Petkov
2020-02-10 15:10 ` Masami Hiramatsu
2020-02-10 17:40 ` Borislav Petkov
2020-02-11 2:02 ` Masami Hiramatsu
2020-02-18 13:27 ` Borislav Petkov
2020-02-18 17:57 ` Steven Rostedt
2020-02-18 19:38 ` Borislav Petkov
2020-02-19 2:26 ` Masami Hiramatsu
2020-02-19 2:26 ` Masami Hiramatsu
2020-02-19 2:26 ` Masami Hiramatsu
2020-02-11 9:25 ` Geert Uytterhoeven
2020-01-14 21:03 ` [for-next][PATCH 05/26] bootconfig: Load boot config from the tail of initrd Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 06/26] tools: bootconfig: Add bootconfig command Steven Rostedt
2020-02-07 13:02 ` Michael Ellerman
2020-02-07 13:39 ` Masami Hiramatsu
2020-02-07 13:55 ` [PATCH] tools/bootconfig: Fix wrong __VA_ARGS__ usage Masami Hiramatsu
2020-02-08 11:10 ` Michael Ellerman
2020-02-09 4:09 ` Masami Hiramatsu
2020-02-09 13:05 ` [PATCH] tools/bootconfig: Suppress non-error messages Masami Hiramatsu
2020-02-10 2:06 ` Michael Ellerman
2020-02-10 7:18 ` Masami Hiramatsu
2020-02-10 9:50 ` Michael Ellerman
2020-02-10 9:50 ` [PATCH] tools/bootconfig: Fix wrong __VA_ARGS__ usage Michael Ellerman
2020-02-10 17:07 ` Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 07/26] tools: bootconfig: Add bootconfig test script Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 08/26] proc: bootconfig: Add /proc/bootconfig to show boot config list Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 09/26] init/main.c: Alloc initcall_command_line in do_initcall() and free it Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 10/26] bootconfig: init: Allow admin to use bootconfig for kernel command line Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 11/26] bootconfig: init: Allow admin to use bootconfig for init " Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 12/26] Documentation: bootconfig: Add a doc for extended boot config Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 13/26] tracing: Apply soft-disabled and filter to tracepoints printk Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 14/26] tracing: kprobes: Output kprobe event to printk buffer Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 15/26] tracing: kprobes: Register to dynevent earlier stage Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 16/26] tracing: Accept different type for synthetic event fields Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 17/26] tracing: Add NULL trace-array check in print_synth_event() Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 18/26] tracing/boot: Add boot-time tracing Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 19/26] tracing/boot: Add per-event settings Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 20/26] tracing/boot Add kprobe event support Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 21/26] tracing/boot: Add synthetic " Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 22/26] tracing/boot: Add instance node support Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 23/26] tracing/boot: Add cpu_mask option support Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 24/26] tracing/boot: Add function tracer filter options Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 25/26] Documentation: tracing: Add boot-time tracing document Steven Rostedt
2020-01-14 21:03 ` [for-next][PATCH 26/26] tracing: trigger: Replace unneeded RCU-list traversals Steven Rostedt
2020-01-14 22:11 ` Steven Rostedt [this message]
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