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Wed, 16 Jul 2025 05:34:47 -0700 (PDT) Received: from [127.0.0.1] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id 8926c6da1cb9f-50556b14173sm2928493173.130.2025.07.16.05.34.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Jul 2025 05:34:46 -0700 (PDT) From: Jens Axboe To: linux-block@vger.kernel.org, Ming Lei Cc: Changhui Zhong In-Reply-To: <20250716114808.3159657-1-ming.lei@redhat.com> References: <20250716114808.3159657-1-ming.lei@redhat.com> Subject: Re: [PATCH] loop: use kiocb helpers to fix lockdep warning Message-Id: <175266928564.266324.4332211753512549130.b4-ty@kernel.dk> Date: Wed, 16 Jul 2025 06:34:45 -0600 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Mailer: b4 0.14.3-dev-2ce6c On Wed, 16 Jul 2025 19:48:08 +0800, Ming Lei wrote: > The lockdep tool can report a circular lock dependency warning in the loop > driver's AIO read/write path: > > ``` > [ 6540.587728] kworker/u96:5/72779 is trying to acquire lock: > [ 6540.593856] ff110001b5968440 (sb_writers#9){.+.+}-{0:0}, at: loop_process_work+0x11a/0xf70 [loop] > [ 6540.603786] > [ 6540.603786] but task is already holding lock: > [ 6540.610291] ff110001b5968440 (sb_writers#9){.+.+}-{0:0}, at: loop_process_work+0x11a/0xf70 [loop] > [ 6540.620210] > [ 6540.620210] other info that might help us debug this: > [ 6540.627499] Possible unsafe locking scenario: > [ 6540.627499] > [ 6540.634110] CPU0 > [ 6540.636841] ---- > [ 6540.639574] lock(sb_writers#9); > [ 6540.643281] lock(sb_writers#9); > [ 6540.646988] > [ 6540.646988] *** DEADLOCK *** > ``` > > [...] Applied, thanks! [1/1] loop: use kiocb helpers to fix lockdep warning commit: c4706c5058a7bd7d7c20f3b24a8f523ecad44e83 Best regards, -- Jens Axboe