From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pz2-f38.google.com (mail-pz2-f38.google.com [74.125.228.38]) (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 432383AEF22 for ; Tue, 29 Sep 2026 07:55:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.228.38 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790668505; cv=none; b=YdER3NWQyjQFGlUaJYYZeHCOY78ocMIEj+eBt+eT/YPeGMgmMGrdyT1EgQjV2FT0/bVOf4wyc0zN2WcSzl0gl2CfkZcMJz03gKv3YUGNdtYTXtX2vOr8EDqwgwUkqIqMuQr6+UTqEBn1rk53gOdbm9sPmmXXj3WPWpToZXXVukg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790668505; c=relaxed/simple; bh=ZPwnTQuqWtBfGDhVm8mEJ/KjEqEJ1mZMGzmHV9RX+P0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=i9R3Hx0Hi4RR/epNHlSmCYrMNmRzo2/h87YyU1CKDI993Z+lvPzgBOEAwXHGvxjqqzFPYi0hni/Ztz9wULvRMUYsSYnL++hoK8QzOwjSxw4lCyfrqMv9PzUcpZLSapqxOB1DbUAQX11xy4JTIQhInF4ttkkjFZZWb9fs2NCshXs= 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=icJoi6F9; arc=none smtp.client-ip=74.125.228.38 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="icJoi6F9" Received: by mail-pz2-f38.google.com with SMTP id d2e1a72fcca58-88272e1d069so1608990b3a.1 for ; Tue, 29 Sep 2026 00:55:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1790668504; x=1791273304; 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=Ulju+lbgB7hZpat+8achefWD3iZ013qQmnKJozx8hJA=; b=icJoi6F9DlxdwEwZeWSci31pJcv3+vnku9VWKo/2Sp29iZhk1pOGU90yKZE7LPrxsB z4wrKe3FZ5UiRZSYCkZPQQPiH/YnnC7TQMzIkQKesifPWouf9X72Lj+jaXLsh9V8+sIJ RMHRoOrszUx0MR6OEZRbvWbHkc5DFS8LDnb2jUi0IZaSmhiAeIvm+EVFKuGHOEW4zOLD LuPrrT+jo+841oxAVTQ4Or7KLjuYm8h9XKo174tgoSFbCsuex87mHt9tsoyKTf3A5agF 7bt9Q0YMD3BWWE995Lb114PlStgLZoTA5HHJAh8B7TiPPnxi/OweMBF0bnDiGDjCVaDd lwLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790668504; x=1791273304; 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=Ulju+lbgB7hZpat+8achefWD3iZ013qQmnKJozx8hJA=; b=tRQHfpkTU4dTZwBGpmMvmEx/omdEB17VlZRqrhBS7yMEcqQryyID2Wjf/uZr7Xvo6v r9vFFOLSsgCWWBkbG/6+J3C1VQSQHWHemxME1nKXxcMSjdgUqbrV7bSkr5Wic1FB/RsW zHWn6yngYoZ148if1fmnVQ2R2jjQRJnPr4vQrogK/Nbxbs/PNl5smWUiVt3N0JDzSSUw eRG38CJTupJoMrFiU2R0HLQQAT6kAGHpSLAn3CBDH3YnGupT1w8vbP41EhaymhTDkeAs IVxTUtuxZERkd1DMgOaTrEOpWZkTaKp0rbb38WKHqrDJihxvxZuY0godgBbNmq3MT1TQ lS9g== X-Gm-Message-State: AFuF++mVbm+kZvm7jBaxqg6NxGfBparBuWgDD2ja5gPFHsAJ97v8BPjN PWg58H/PZCQNiNAisP82GQmr8J5s9glLIzDp03zJtQ55ahfnRfEx40n2 X-Gm-Gg: AYBFou3uH7LTIsHpz8LIN8GdZGGJmaGD3zPSKxOpUNzrew7BnoMu9cZAjGn+n7XDvGh wMqpLyWcK8b/vxDhKqEXN7mob3L9mMfGFOkthodCZaBSkQ7rkFj+HIXNQq31CUHK3//Y2qevn9c tespmkw/SR7lrQ3QCskocfx/xv/bNH4fDmeHBzyBvuwhwOFXgv7gdIgrR+EPQSYS4Wqtt/H6Jf9 sgtNuNc3NyjhH7ids3NFYvDGC82gLReZVz4r7yKE8voaLH4N/4KGLIA5ObCI2F7OOPyJH1gQjCA Y3hw+QH+jzck2jCsBHMFEXssIynpbXUKufLmJSD0DKQPV5/2cLF+7YiWHy/YDQe+gZAsvU/boSm at69dhowN/CsZrvhKtfefDqGQHmnWeg+GwV2tcsTtmtTxTmAsjFJ49WTeCAmVuVH61r7pQHFlfT ZQU+lQZzJKNdBslYuDRFa4EumlyFpM4cH92npFEPhuFUedyFtY+dmf6pXV+EnnB/bkJijhRVpbs J3UnpPSMZFTarWPig== X-Received: by 2002:a05:6a00:1795:b0:880:b709:cefb with SMTP id d2e1a72fcca58-880b709fc95mr8242883b3a.45.1790668503728; Tue, 29 Sep 2026 00:55:03 -0700 (PDT) Received: from embedsky001.tail6d6b2f.ts.net ([183.12.106.39]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-885e22ee338sm351772b3a.45.2026.09.29.00.55.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Sep 2026 00:55:03 -0700 (PDT) From: Yonghao Zhang To: andersson@kernel.org, mathieu.poirier@linaro.org Cc: linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, Yonghao Zhang Subject: [PATCH 1/4] remoteproc: core: Reset freed vring entries to FW_RSC_ADDR_ANY Date: Tue, 29 Sep 2026 15:54:50 +0800 Message-Id: <20260929075453.2324597-2-hyz3367@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260929075453.2324597-1-hyz3367@gmail.com> References: <20260929075453.2324597-1-hyz3367@gmail.com> Precedence: bulk X-Mailing-List: linux-remoteproc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit rproc_free_vring() resets a vring entry in the resource table as it releases it. Resetting da to 0 leaves the entry looking like a vring at device address 0; write FW_RSC_ADDR_ANY instead, the marker for an unallocated address, which is what the entry means from then on. That matters on the error paths of rproc_start() and rproc_attach(), where rproc_free_vring() runs while the remote processor is already running: the failure originates in rp_find_vq(), called through virtio_find_vqs() from e.g. rpmsg_probe(), which the core only reaches through rproc_start_subdevices(), after ops->start() or ops->attach() have completed. At that point table_ptr is the resource table installed in remote processor memory, and whatever the reset writes is visible to the remote side. Whether and when a running processor reads the entry cannot be known, so the value must be safe for one: 0 is a plausible device address, FW_RSC_ADDR_ANY is not. On the teardown paths, stop and detach, the write lands in the cached table or in a copy of the installed one and reaches no one. The comment replaced along with it was written for a call graph that no longer exists. It described the teardown callers only: rproc_stop() has run, table_ptr points at the cached table, and that table is NULL for a processor started by another entity, so there is nothing to clear. Two facts have overtaken it: - rp_find_vq() has been calling rproc_free_vring() when vring_new_virtqueue() fails since commit 6db20ea8d850 ("remoteproc: allocate vrings on demand, free when not needed"), and that call was present, unchanged, when commit 9dc9507f1880 ("remoteproc: Properly deal with the resource table when detaching") landed: it runs from rproc_start_subdevices(), after ops->start() or ops->attach() have completed, with table_ptr at the table installed in remote processor memory and the processor running. The comment never described this caller, not on the day it was written. - commit 9dc9507f1880 ("remoteproc: Properly deal with the resource table when detaching") and commit 8088dd4d9316 ("remoteproc: Properly deal with the resource table when stopping") later taught the detach/stop paths to take a kmemdup() copy of the installed table for processors started by another entity, so the NULL case the guard was deciding between is gone: table_ptr is always valid where the teardown callers run. (Those callers have since moved to the rproc-virtio platform driver, 9c31255ce5fe.) Fixes: c0d631570ad5 ("remoteproc: set vring addresses in resource table") Fixes: 4d3ebb3b9990 ("remoteproc: Refactor function rproc_free_vring()") Signed-off-by: Yonghao Zhang --- drivers/remoteproc/remoteproc_core.c | 40 +++++++++++++++++++--------- 1 file changed, 28 insertions(+), 12 deletions(-) diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c index 263e12f022ea..123aadb467a0 100644 --- a/drivers/remoteproc/remoteproc_core.c +++ b/drivers/remoteproc/remoteproc_core.c @@ -403,6 +403,33 @@ rproc_parse_vring(struct rproc_vdev *rvdev, struct fw_rsc_vdev *rsc, int i) return 0; } +/* + * rproc_free_vring() runs while a remote processor is being torn down + * (rproc_stop()/rproc_detach() paths) or while a boot or attach attempt + * is failing. Whether the reset below can reach the remote processor + * depends on what rproc->table_ptr refers to at that point: + * + * - teardown paths: the call comes from the rvdev cleanup in + * rproc_resource_cleanup(), by which time rproc_stop()/__rproc_detach() + * have switched table_ptr to the table the core was booted with, or + * to a copy of the installed table when the remote processor was + * started by another entity (rproc_reset_rsc_table_on_{stop,detach}()), + * so the write cannot reach the remote processor. + * + * - error paths of rproc_start()/rproc_attach(): the failure originates + * in rp_find_vq() (virtio_find_vqs() failing in e.g. rpmsg_probe()), + * which rproc_start_subdevices() calls only once ops->start() or + * ops->attach() have completed. table_ptr still points at the + * resource table installed in remote processor memory and the remote + * processor is already running. + * + * Especially in the last case the reset has to tell the remote + * processor that the vring entry is not usable: with da set to the + * invalid FW_RSC_ADDR_ANY a running remote processor sees the address + * as unallocated, and notifyid is invalidated along with it. + * + * Reset the virtio device section only if there is a table to work with. + */ void rproc_free_vring(struct rproc_vring *rvring) { struct rproc *rproc = rvring->rvdev->rproc; @@ -411,20 +438,9 @@ void rproc_free_vring(struct rproc_vring *rvring) idr_remove(&rproc->notifyids, rvring->notifyid); - /* - * At this point rproc_stop() has been called and the installed resource - * table in the remote processor memory may no longer be accessible. As - * such and as per rproc_stop(), rproc->table_ptr points to the cached - * resource table (rproc->cached_table). The cached resource table is - * only available when a remote processor has been booted by the - * remoteproc core, otherwise it is NULL. - * - * Based on the above, reset the virtio device section in the cached - * resource table only if there is one to work with. - */ if (rproc->table_ptr) { rsc = (void *)rproc->table_ptr + rvring->rvdev->rsc_offset; - rsc->vring[idx].da = 0; + rsc->vring[idx].da = FW_RSC_ADDR_ANY; rsc->vring[idx].notifyid = -1; } } -- 2.34.1