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From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: qemu-devel@nongnu.org
Cc: "Phil Dennis-Jordan" <phil@philjordan.eu>,
	"Pierrick Bouvier" <pierrick.bouvier@linaro.org>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Mads Ynddal" <mads@ynddal.dk>,
	"Alexander Graf" <agraf@csgraf.de>,
	"Cameron Esfahani" <dirty@apple.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Roman Bolshakov" <rbolshakov@ddn.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	qemu-arm@nongnu.org,
	"Manos Pitsidianakis" <manos.pitsidianakis@linaro.org>
Subject: [PATCH 2/4] cpus: Access CPUState::thread_kicked atomically
Date: Thu, 25 Sep 2025 04:55:17 +0200	[thread overview]
Message-ID: <20250925025520.71805-3-philmd@linaro.org> (raw)
In-Reply-To: <20250925025520.71805-1-philmd@linaro.org>

cpus_kick_thread() is called via cpu_exit() -> qemu_cpu_kick(),
and also via gdb_syscall_handling(). Access the CPUState field
using atomic accesses. See commit 8ac2ca02744 ("accel: use atomic
accesses for exit_request") for rationale.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 system/cpus.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/system/cpus.c b/system/cpus.c
index 6062226d4ac..818a8047198 100644
--- a/system/cpus.c
+++ b/system/cpus.c
@@ -480,10 +480,10 @@ void qemu_process_cpu_events(CPUState *cpu)
 
 void cpus_kick_thread(CPUState *cpu)
 {
-    if (cpu->thread_kicked) {
+    if (qatomic_read(&cpu->thread_kicked)) {
         return;
     }
-    cpu->thread_kicked = true;
+    qatomic_set(&cpu->thread_kicked, true);
 
 #ifndef _WIN32
     int err = pthread_kill(cpu->thread->thread, SIG_IPI);
-- 
2.51.0



  parent reply	other threads:[~2025-09-25  2:57 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-25  2:55 [PATCH 0/4] cpus: Cleanups around cpu running state changes Philippe Mathieu-Daudé
2025-09-25  2:55 ` [PATCH 1/4] cpus: Only resume halted CPUs Philippe Mathieu-Daudé
2025-09-25  8:34   ` Philippe Mathieu-Daudé
2025-09-25  2:55 ` Philippe Mathieu-Daudé [this message]
2025-09-29  5:52   ` [PATCH 2/4] cpus: Access CPUState::thread_kicked atomically Manos Pitsidianakis
2025-09-25  2:55 ` [PATCH 3/4] accel/hvf: Make async_safe_run_on_cpu() safe Philippe Mathieu-Daudé
2025-09-26  0:13   ` Richard Henderson
2025-09-25  2:55 ` [PATCH 4/4] accel/tcg: Use cpu_is_stopped() helper to access CPUState::stopped Philippe Mathieu-Daudé
2025-09-26  0:44   ` Richard Henderson

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