From 08acb54b063a33730eb1ae1e0f89bf36542bac9f Mon Sep 17 00:00:00 2001 From: Xixin Liu Date: Wed, 19 Aug 2026 08:50:00 +0800 Subject: [PATCH] nvme-tcp: defer TLS inline send to io_work blk_mq holds set->srcu while queuing and running requests. The kTLS software send path takes ctx->tx_lock. lockdep knows that tx_lock nests under elevator_lock which then waits on srcu, so an inline send from that path under TLS triggers circular locking. Skip the inline send optimization for TLS queues so the send runs from the workqueue instead. The same workqueue already retries TLS sends on write-space notifications. Plain TCP keeps the inline path. Fixes: be8e82caa685 ("nvme-tcp: enable TLS handshake upcall") Reviewed-by: Hannes Reinecke Signed-off-by: Xixin Liu Signed-off-by: Keith Busch --- drivers/nvme/host/tcp.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 2a15c6143f2a..921934028e0b 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -413,8 +413,13 @@ static inline void nvme_tcp_queue_request(struct nvme_tcp_request *req, * if we're the first on the send_list and we can try to send * directly, otherwise queue io_work. Also, only do that if we * are on the same cpu, so we don't introduce contention. + * + * TLS kTLS send takes ctx->tx_lock while blk_mq holds set->srcu. + * lockdep reports circular locking via elevator_lock. Defer TLS + * sends to the io workqueue instead of inline from this path. */ if (queue->io_cpu == raw_smp_processor_id() && + !nvme_tcp_queue_tls(queue) && empty && mutex_trylock(&queue->send_mutex)) { nvme_tcp_send_all(queue); mutex_unlock(&queue->send_mutex);