From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE7143AE45 for ; Wed, 7 Jun 2023 20:27:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DD08C433D2; Wed, 7 Jun 2023 20:27:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686169674; bh=6JCHwVKxkQsQPrUJDGy2mxc74mHzyJx+YWHEXdPHPCs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aOYyIHe3Z3S4Da6qXOGfjGGqW8PpABpBld05StxsXT7wiSHy+9B2/upr2UQEciMCg YRdBYmofxZFmWqB3kI+SbMziRh8oyunWH/joM2Arpa9dpS293slNNsZgU5Q3xz2lgC ml5YxGjHT/Pofe2UQXRq9BQ9Mt7lufJJLVZMhvDA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shinichiro Kawasaki , Ziyang Zhang , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 6.3 171/286] ublk: fix AB-BA lockdep warning Date: Wed, 7 Jun 2023 22:14:30 +0200 Message-ID: <20230607200928.711055203@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230607200922.978677727@linuxfoundation.org> References: <20230607200922.978677727@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ming Lei [ Upstream commit ac5902f84bb546c64aea02c439c2579cbf40318f ] When handling UBLK_IO_FETCH_REQ, ctx->uring_lock is grabbed first, then ub->mutex is acquired. When handling UBLK_CMD_STOP_DEV or UBLK_CMD_DEL_DEV, ub->mutex is grabbed first, then calling io_uring_cmd_done() for canceling uring command, in which ctx->uring_lock may be required. Real deadlock only happens when all the above commands are issued from same uring context, and in reality different uring contexts are often used for handing control command and IO command. Fix the issue by using io_uring_cmd_complete_in_task() to cancel command in ublk_cancel_dev(ublk_cancel_queue). Reported-by: Shinichiro Kawasaki Closes: https://lore.kernel.org/linux-block/becol2g7sawl4rsjq2dztsbc7mqypfqko6wzsyoyazqydoasml@rcxarzwidrhk Cc: Ziyang Zhang Signed-off-by: Ming Lei Tested-by: Shinichiro Kawasaki Link: https://lore.kernel.org/r/20230517133408.210944-1-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/ublk_drv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 41c35ab2c25a1..4db5f1bcac44a 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1122,6 +1122,11 @@ static inline bool ublk_queue_ready(struct ublk_queue *ubq) return ubq->nr_io_ready == ubq->q_depth; } +static void ublk_cmd_cancel_cb(struct io_uring_cmd *cmd, unsigned issue_flags) +{ + io_uring_cmd_done(cmd, UBLK_IO_RES_ABORT, 0, issue_flags); +} + static void ublk_cancel_queue(struct ublk_queue *ubq) { int i; @@ -1133,8 +1138,8 @@ static void ublk_cancel_queue(struct ublk_queue *ubq) struct ublk_io *io = &ubq->ios[i]; if (io->flags & UBLK_IO_FLAG_ACTIVE) - io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0, - IO_URING_F_UNLOCKED); + io_uring_cmd_complete_in_task(io->cmd, + ublk_cmd_cancel_cb); } /* all io commands are canceled */ -- 2.39.2