From af2962d68b970b15d8910be2b0386b4f147ed78b Mon Sep 17 00:00:00 2001 From: Wander Lairson Costa Date: Tue, 6 Jan 2026 08:49:51 -0300 Subject: [PATCH] rtla: Make stop_tracing variable volatile The stop_tracing global variable is accessed from both the signal handler context and the main program flow without synchronization. This creates a potential race condition where compiler optimizations could cache the variable value in registers, preventing the signal handler's updates from being visible to other parts of the program. 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. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260106133655.249887-16-wander@redhat.com Signed-off-by: Tomas Glozar --- tools/tracing/rtla/src/common.c | 2 +- tools/tracing/rtla/src/common.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/tracing/rtla/src/common.c b/tools/tracing/rtla/src/common.c index 6f64c1fc1b621..ceff76a62a30b 100644 --- a/tools/tracing/rtla/src/common.c +++ b/tools/tracing/rtla/src/common.c @@ -10,7 +10,7 @@ #include "common.h" struct trace_instance *trace_inst; -int stop_tracing; +volatile int stop_tracing; static void stop_trace(int sig) { diff --git a/tools/tracing/rtla/src/common.h b/tools/tracing/rtla/src/common.h index ef17ea5be540a..7602c5593ef5d 100644 --- a/tools/tracing/rtla/src/common.h +++ b/tools/tracing/rtla/src/common.h @@ -54,7 +54,7 @@ struct osnoise_context { }; extern struct trace_instance *trace_inst; -extern int stop_tracing; +extern volatile int stop_tracing; struct hist_params { char no_irq; -- 2.47.3