From: Crystal Wood <crwood@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>,
Wander Lairson Costa <wander@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>,
Ivan Pravdin <ipravdin.official@gmail.com>,
Costa Shulyupin <costa.shul@redhat.com>,
John Kacur <jkacur@redhat.com>,
Tiezhu Yang <yangtiezhu@loongson.cn>,
"open list:Real-time Linux Analysis (RTLA) tools"
<linux-trace-kernel@vger.kernel.org>,
"open list:Real-time Linux Analysis (RTLA) tools"
<linux-kernel@vger.kernel.org>,
"open list:BPF [MISC]:Keyword:(?:\\b|_)bpf(?:\\b|_)"
<bpf@vger.kernel.org>
Subject: Re: [PATCH v2 15/18] rtla: Make stop_tracing variable volatile
Date: Tue, 06 Jan 2026 11:47:56 -0600 [thread overview]
Message-ID: <d40f598776e7995c9f1559514e89ccff51d91f9c.camel@redhat.com> (raw)
In-Reply-To: <20260106110519.40c97efe@gandalf.local.home>
On Tue, 2026-01-06 at 11:05 -0500, Steven Rostedt wrote:
> On Tue, 6 Jan 2026 08:49:51 -0300
> Wander Lairson Costa <wander@redhat.com> wrote:
>
> > Add the volatile qualifier to stop_tracing in both common.c and
> > common.h to ensure all accesses to this variable bypass compiler
> > optimizations and read directly from memory. This guarantees that
> > when the signal handler sets stop_tracing, the change is immediately
> > visible to the main program loop, preventing potential hangs or
> > delayed shutdown when termination signals are received.
>
> In the kernel, this is handled via the READ_ONCE() macro. Perhaps rtla
> should implement that too.
Or just get it from tools/include/linux/compiler.h. No need to reinvent
the wheel (even though several other tools do).
That said, signal safety is a pretty routine use for volatile.
-Crystal
next prev parent reply other threads:[~2026-01-06 17:48 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-06 11:49 [PATCH v2 00/18] rtla: Code quality and robustness improvements Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 01/18] rtla: Exit on memory allocation failures during initialization Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 02/18] rtla: Use strdup() to simplify code Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 03/18] rtla: Introduce for_each_action() helper Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 04/18] rtla: Replace atoi() with a robust strtoi() Wander Lairson Costa
2026-01-12 12:27 ` Costa Shulyupin
2026-01-12 12:39 ` Tomas Glozar
2026-01-06 11:49 ` [PATCH v2 05/18] rtla: Simplify argument parsing Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 06/18] rtla: Use strncmp_static() in more places Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 07/18] rtla: Introduce common_restart() helper Wander Lairson Costa
2026-01-07 12:03 ` Tomas Glozar
2026-01-07 12:43 ` Wander Lairson Costa
2026-01-07 13:47 ` Tomas Glozar
2026-01-07 13:50 ` Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 08/18] rtla: Use standard exit codes for result enum Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 09/18] rtla: Remove redundant memset after calloc Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 10/18] rtla: Replace magic number with MAX_PATH Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 11/18] rtla: Remove unused headers Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 12/18] rtla: Fix NULL pointer dereference in actions_parse Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 13/18] rtla: Fix buffer size for strncpy in timerlat_aa Wander Lairson Costa
2026-01-06 16:03 ` Steven Rostedt
2026-01-07 13:20 ` Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 14/18] rtla: Add generated output files to gitignore Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 15/18] rtla: Make stop_tracing variable volatile Wander Lairson Costa
2026-01-06 16:05 ` Steven Rostedt
2026-01-06 17:47 ` Crystal Wood [this message]
2026-01-07 13:24 ` Wander Lairson Costa
2026-01-07 16:31 ` Steven Rostedt
2026-01-06 11:49 ` [PATCH v2 16/18] rtla: Ensure null termination after read operations in utils.c Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 17/18] rtla: Fix parse_cpu_set() return value documentation Wander Lairson Costa
2026-01-06 11:49 ` [PATCH v2 18/18] rtla: Simplify code by caching string lengths Wander Lairson Costa
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