From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj2-f13.google.com (mail-pj2-f13.google.com [74.125.227.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9028F47B437 for ; Tue, 15 Sep 2026 09:43:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.227.141 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789465391; cv=none; b=jhbIiko+fIf0Lym+aUAATZB0suQtY+ZQBotLj04C0TDYN63QNaQr38hbF4V5taV+b3YwYKaI7RI2C18Nqcfn0smjCcia3uq3NuS1RfXQFdOPSKnZtgnSNn78kWbOyAY2MqNGwl6qPHx4MPOT6uo6E0nZMwXOw/lqeOBOk9wUtOs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789465391; c=relaxed/simple; bh=Y/Ynb8CMg23HSLFnvahuALwqonYoPmDH12RAnxUrtaY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=MeDeXcT6HFV/hS5ZlnvYMIr6Blxi1Fp3GAMYsVQG1fERUJjTz+AmP8unOHTAKgJvnTlNHOh1wzMw3MiLWPOf83DCuKrflnrOMovp0cs3al/RIBHrHksDMmP9QA6sOcJ0CRrMtPNO5S1jS4sZSjWaFXBT4kMrGjzPhM6CJyfzMpA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=qeUfdszM; arc=none smtp.client-ip=74.125.227.141 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qeUfdszM" Received: by mail-pj2-f13.google.com with SMTP id d9443c01a7336-2d747f0135fso27192695ad.0 for ; Tue, 15 Sep 2026 02:43:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789465386; x=1790070186; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=X5e+gRweobBjhlv/HMhSt0aHVe80wymGJQQad+R8SpY=; b=qeUfdszMaM8E/1D8kFzgNSRUoHbyP9Yii92IZgP4xBd7RvloXZYhmcBmT9betpSGBf ODhL95zZ9a4gwo82AbZqQ1+ICaaSSPH1Hxh6lyeW0V7n2KrtMaINz6EBj4XTwCTxoq/u 38VI8hG+/TdSx7Q3dAL2r/wDZbfx1wlEZNVQGx8lQlqXrnmZQCAIvTdb5ZJM7km2umAl gAlXB+G5ECkqDHsurBbhuXg+ij9zt5tz8KwrlBF7q53OCYmvyFw3syscPFNXG/AJRznM GDIzS8oJNcp4d1gDL1lYYNzsF1jCbp9g+dJGm+XIW/a5sb0Sx8x8XkGOGEdr6VaK0ITd e6vQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789465386; x=1790070186; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=X5e+gRweobBjhlv/HMhSt0aHVe80wymGJQQad+R8SpY=; b=Df/F8my5OdoWkvwh6pHGFKNWYBjf2BPtqUzhpgJ0GLYTjbLqVlAllTOo0Q13PnY+9N hOU8ku2il5IDSBecZRJU3tzu1jumRiCnn228SiOXJpCO19iNHYVqjaQrc/Eo4eCach6B 2dNsMenP6PND5VAyvKBoj5kZngRXN6y5NNqGrXGneFjcU5Uj4pCmraX0ks+MVFaLNepC SLOUfNo1GZQw9lMisCy8+EtagAPLlHpWNLZKHXgjbQLGu8MAlB+r3R7BNlSlvfEbF0BU acbTJK3VP1G1pg5Sut21h/jiGFIR+B2TUzoYS9sv1sObEkTV/Dz0IotLlpzOVo7F1BsR kSSg== X-Forwarded-Encrypted: i=1; AKwUvBzIvHAlg7mh+4HBDDWupYx/c4tjM0bgmHjBDM/uVoM/w8ZiOxBWFQww9M0836uRLc9PRZ/POCd/XXxRGQU=@vger.kernel.org X-Gm-Message-State: AFuF++noIqcvvSXiI9SZtDJRtG+UYoeB3liEvXyqyxGiCfaJQ83SpXB/ sah5kpRpuRCTRCO3ipGTWX4JsQrrLMJ+Lc5K5At7KcLMUREM0t09Dfv8 X-Gm-Gg: AYBFou27AaKCO2vmZzOI78ARF3BGPgduUCPlchmjfT1BJ5vfXxJyb7Q0HP0R070yqKl hH9KOzvK1BVOj1zolKEUvU91ACwnT+8WW7n5OERfOYiGIpprQVE8rsPOj6FuMymhSV0OHLp8oi+ BQvxjGZ64MpE4+o1ivh3FdQXOh/YmJYBh6bokRU4qjEQjYwcyE3ILJeT4OhlAkJOvC7txy83tph xYVs7i+Uzft9zOplvVUuzkHl/HO5hbKuojguMkBp/ETYuVRgBGOj79ur8BWu8hH5C9zc1kbdjWA 0Jgy3BKj+jUfJ66nB1er2Cp/Lxdj+L1JhypclQNrh4iUu54ipNBSzLTVKXUO4Lf97Z3gIZ6MTOi LLZpTFMGXz/iU+Y1XmfaZgez47Yhg8wg1ZXI/pIQakSEH4Z3u8E2mxbPUeRI3CIHsuq4Az5kDLR pjLgBL+IRg31gFbwo8mIQCZ/HO8QrqXTLZ4R8ZMYM7vguRvyIWWRsXNl49IJUu9Jw= X-Received: by 2002:a17:90a:c2cd:b0:39d:f2a1:3a with SMTP id 98e67ed59e1d1-39df2a10424mr10688797a91.15.1789465386330; Tue, 15 Sep 2026 02:43:06 -0700 (PDT) Received: from jia ([188.253.12.32]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39dfdd0ada3sm4269410a91.8.2026.09.15.02.43.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Sep 2026 02:43:06 -0700 (PDT) From: physicalmtea@gmail.com To: mst@redhat.com Cc: jasowangio@gmail.com, michael.christie@oracle.com, pbonzini@redhat.com, stefanha@redhat.com, eperezma@redhat.com, nab@linux-iscsi.org, asias@redhat.com, virtualization@lists.linux.dev, kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] vhost-scsi: do not relock event vq mutex on send_evt fallback Date: Tue, 15 Sep 2026 17:42:44 +0800 Message-Id: <20260915094244.7900-3-physicalmtea@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260915094244.7900-1-physicalmtea@gmail.com> References: <20260915094244.7900-1-physicalmtea@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jia Jia vhost_scsi_send_evt() is called with the event virtqueue mutex held. If the worker is gone, the fallback currently calls vhost_scsi_complete_events(), which tries to acquire the same mutex again and deadlocks the caller. Split event completion into a helper for callers that already hold the mutex and a locking wrapper for the event worker. Use the helper on the fallback path. Link: https://lore.kernel.org/all/20260905005352.1E5B01F00A3D@smtp.kernel.org/ Fixes: b1b2ce58ed23 ("vhost-scsi: Handle vhost_vq_work_queue failures for events") Signed-off-by: Jia Jia Reviewed-by: Mike Christie --- drivers/vhost/scsi.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 37f681aab..9cd181cb1 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -630,19 +630,26 @@ vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt) vhost_scsi_log_write(vq, vq_log, log_num); } -static void vhost_scsi_complete_events(struct vhost_scsi *vs, bool drop) +/* Caller must hold the event virtqueue mutex. */ +static void __vhost_scsi_complete_events(struct vhost_scsi *vs, bool drop) { - struct vhost_virtqueue *vq = &vs->vqs[VHOST_SCSI_VQ_EVT].vq; struct vhost_scsi_evt *evt, *t; struct llist_node *llnode; - mutex_lock(&vq->mutex); llnode = llist_reverse_order(llist_del_all(&vs->vs_event_list)); llist_for_each_entry_safe(evt, t, llnode, list) { if (!drop) vhost_scsi_do_evt_work(vs, evt); vhost_scsi_free_evt(vs, evt); } +} + +static void vhost_scsi_complete_events(struct vhost_scsi *vs, bool drop) +{ + struct vhost_virtqueue *vq = &vs->vqs[VHOST_SCSI_VQ_EVT].vq; + + mutex_lock(&vq->mutex); + __vhost_scsi_complete_events(vs, drop); mutex_unlock(&vq->mutex); } @@ -1829,7 +1836,7 @@ vhost_scsi_send_evt(struct vhost_scsi *vs, struct vhost_virtqueue *vq, llist_add(&evt->list, &vs->vs_event_list); if (!vhost_vq_work_queue(vq, &vs->vs_event_work)) - vhost_scsi_complete_events(vs, true); + __vhost_scsi_complete_events(vs, true); } static void vhost_scsi_evt_handle_kick(struct vhost_work *work) -- 2.34.1