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Wed, 28 Oct 2026 19:57:45 +0000 (UTC) From: Bart Van Assche To: Jens Axboe , Josef Bacik , Chris Mason Cc: Justin Sanders , linux-block@vger.kernel.org, Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni Subject: Re: [PATCH 90/98] nvmet-rdma: disable interrupts under rsp_wr_wait_lock Date: Wed, 28 Oct 2026 12:57:20 -0700 Message-ID: <20261028195731.1591331-8-bvanassche@acm.org> X-Mailer: git-send-email 2.56.0.313.g2479322e68-goog In-Reply-To: <20261028164415.1262013-91-axboe@kernel.dk> References: <20261028164415.1262013-1-axboe@kernel.dk> <20261028164415.1262013-91-axboe@kernel.dk> X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On 10/28/26 09:42, Jens Axboe wrote: > - spin_unlock(&queue->rsp_wr_wait_lock); > + spin_unlock_irqrestore(&queue->rsp_wr_wait_lock, flags); > ret =3D nvmet_rdma_execute_command(rsp); > - spin_lock(&queue->rsp_wr_wait_lock); > + spin_lock_irqsave(&queue->rsp_wr_wait_lock, flags); Using spin_lock_irqsave() fixes the rsp_wr_wait_lock deadlock itself, but when nvmet_rdma_process_wr_wait_list() is reached from a bio end_io callback in hardirq or softirq context (via nvmet_req_complete() -> nvmet_rdma_queue_response() -> failed ib_post_send() -> nvmet_rdma_release_rsp()), spin_unlock_irqrestore() restores that hardirq/softirq context and calls nvmet_rdma_execute_command(rsp) -> rsp->req.execute(&rsp->req). The nvmet ->execute() handlers assume process context: - nvmet_bdev_execute_rw() allocates bios with GFP_KERNEL and calls submit_bio() -> submit_bio_noacct(), which hits might_sleep() and manipulates current->bio_list without interrupt synchronization. - Admin, fabrics, auth, and PR handlers perform GFP_KERNEL allocations and take mutexes / rwsems. Shouldn't rsp_wr_wait_list processing be deferred to a work_struct when !in_task() (or whenever nvmet_rdma_release_rsp() is called from atomic context)?