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[88.187.86.199]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46fb482ba41sm200512545e9.4.2025.10.13.12.07.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Oct 2025 12:07:03 -0700 (PDT) Message-ID: <89f61779-e078-4778-a8ef-d5a507c46f28@linaro.org> Date: Mon, 13 Oct 2025 21:07:02 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] async: access bottom half flags with qatomic_read Content-Language: en-US To: Paolo Bonzini , qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, qemu-stable@nongnu.org References: <20251013162620.995747-1-pbonzini@redhat.com> From: =?UTF-8?Q?Philippe_Mathieu-Daud=C3=A9?= In-Reply-To: <20251013162620.995747-1-pbonzini@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::444; envelope-from=philmd@linaro.org; helo=mail-wr1-x444.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 13/10/25 18:26, Paolo Bonzini wrote: > Running test-aio-multithread under TSAN reveals data races on bh->flags. > Because bottom halves may be scheduled or canceled asynchronously, > without taking a lock, adjust aio_compute_bh_timeout() and aio_ctx_check() > to use a relaxed read to access the flags. > > Use an acquire load to ensure that anything that was written prior to > qemu_bh_schedule() is visible. > > Resolves: #2749 > Resolves: #851 Preferably using the full URL: https://gitlab.com/qemu-project/qemu/-/issues/851 https://gitlab.com/qemu-project/qemu/-/issues/2749 > Cc: qemu-stable@nongnu.org > Signed-off-by: Paolo Bonzini > --- > util/async.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) Reviewed-by: Philippe Mathieu-Daudé