From nobody Mon May 25 02:57:19 2026 Received: from esa7.hc1455-7.c3s2.iphmx.com (esa7.hc1455-7.c3s2.iphmx.com [139.138.61.252]) (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 D803B1FBC8E; Tue, 19 May 2026 10:19:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=139.138.61.252 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779185960; cv=none; b=MeeLzh8Aft6CM2E+pO/XHwokDeTwUNYwyN/4tVg9mjYhPWSh9xY3K58PGFCHkC0TK+BIqLVlnCiGDx1rNXiMr3Ib2zAL2pi3f8Mp9srH6OD/uRACxn/lm0y3ywxm8o8wn1dedG7yzC7y7pzJCKG7bsvaFwolqntdY9imAhg2qBQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779185960; c=relaxed/simple; bh=2nMw25pjO6lFmqT9ORMlFdHwuDJXpu902r+c+Vb1lIQ=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=mKsTDTE27Iyxqef9Uu8cdD1WKU5P6uPvTQW/FxOaWysU0YrIB62V3F70kEx6TMGEyNZHzbOniK32goW+/Vs9ZlMWwsciH1tQQ78NhGo3X519XntRQLasIqFbpSZs11+LczVwL/2Itb5wQShwZ3tmRGxuvuv/P32WlG/osoreJ1Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fujitsu.com; spf=pass smtp.mailfrom=fujitsu.com; dkim=pass (2048-bit key) header.d=fujitsu.com header.i=@fujitsu.com header.b=lS9psYwV; arc=none smtp.client-ip=139.138.61.252 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fujitsu.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fujitsu.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fujitsu.com header.i=@fujitsu.com header.b="lS9psYwV" DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=fujitsu.com; i=@fujitsu.com; q=dns/txt; s=fj2; t=1779185959; x=1810721959; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=2nMw25pjO6lFmqT9ORMlFdHwuDJXpu902r+c+Vb1lIQ=; b=lS9psYwVJEewmLmOIgxuceZ6H7NswRY1wh6jaGfZQduwrgGb3CqCmP2r N2v5SQQ0yEKse0klup7pqGfK7rSjKt33WBgwgiIEQpOnE4utWmD26DB/1 yzA1kcNFhi1Phup1DhqXCqoQ3jQ2r1Jivh2JgqV9oevT1CBQkPyjbKkru 7hTc+eb0TxA/natP38C7pKVj0l5x/aSksEfondxXLwT5+hLmiUdAzUO1b jrjvoX6sVcRYPXoGsIpctNcPrW6CQRscvXI9G5fgXvtTm3QFhBnd7xp1Q +uAf/2E+TFCGSVSHxxMQ9ecinQaUWB3rT6VVO7o3yRS4D6JRdulr2Ho/4 w==; X-CSE-ConnectionGUID: yX1WoJh/Teu3DOU2V92u6Q== X-CSE-MsgGUID: aktgorI/SH+YZcBLlG2oLg== X-IronPort-AV: E=McAfee;i="6800,10657,11790"; a="219990140" X-IronPort-AV: E=Sophos;i="6.23,243,1770562800"; d="scan'208";a="219990140" Received: from gmgwuk01.global.fujitsu.com ([172.187.114.235]) by esa7.hc1455-7.c3s2.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 May 2026 19:19:17 +0900 Received: from az2uksmgm2.o.css.fujitsu.com (unknown [10.151.22.199]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by gmgwuk01.global.fujitsu.com (Postfix) with ESMTPS id 01F121002B9C; Tue, 19 May 2026 10:19:17 +0000 (UTC) Received: from az2uksmom4.o.css.fujitsu.com (az2uksmom4.o.css.fujitsu.com [10.151.22.204]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by az2uksmgm2.o.css.fujitsu.com (Postfix) with ESMTPS id AC702181AA53; Tue, 19 May 2026 10:19:16 +0000 (UTC) Received: from dhcp-portal (unknown [10.172.107.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by az2uksmom4.o.css.fujitsu.com (Postfix) with ESMTPS id 4CB8A4066E3; Tue, 19 May 2026 10:19:15 +0000 (UTC) Received: from isar2.ecs00.fujitsu.local (unknown [10.172.183.27]) by dhcp-portal (Postfix) with ESMTP id E013460A9D; Tue, 19 May 2026 12:19:13 +0200 (CEST) From: Tomasz Wolski To: smita.koralahallichannabasappa@amd.com, alison.schofield@intel.com, dan.j.williams@intel.com Cc: icheng@nvidia.com, linux-cxl@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, nvdimm@lists.linux.dev, ardb@kernel.org, benjamin.cheatham@amd.com, dave.jiang@intel.com, jonathan.cameron@huawei.com, Tomasz Wolski Subject: [PATCH v2] dax/bus: Upgrade resource conflict message to dev_err() in alloc_dax_region() Date: Tue, 19 May 2026 12:18:32 +0200 Message-Id: <20260519101832.31988-1-tomasz.wolski@fujitsu.com> X-Mailer: git-send-email 2.35.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The dax_region resource conflict in alloc_dax_region() indicates a serious configuration problem =E2=80=94 two subsystems (e.g. dax_hmem and dax_cxl) are attempting to register overlapping address ranges. This is not a transient or debug-level condition; it represents a genuine resource conflict that an administrator needs to be aware of. Switch from request_resource() + dev_dbg() to request_resource_conflict() + dev_err() so that the conflict is visible by default and the colliding resource is identified in the message. Suggested-by: Dan Williams Link: https://lore.kernel.org/linux-cxl/69c1a8d1c0fa9_7ee3100a1@dwillia2-mo= bl4.notmuch/ Signed-off-by: Tomasz Wolski Reviewed-by: Jonathan Cameron Reviewed-by: Richard Cheng --- drivers/dax/bus.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 68437c05e21d..66413c6c2ba0 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -637,7 +637,7 @@ struct dax_region *alloc_dax_region(struct device *pare= nt, int region_id, unsigned long flags) { struct dax_region *dax_region; - int rc; + struct resource *conflict; =20 /* * The DAX core assumes that it can store its private data in @@ -670,10 +670,11 @@ struct dax_region *alloc_dax_region(struct device *pa= rent, int region_id, .flags =3D IORESOURCE_MEM | flags, }; =20 - rc =3D request_resource(&dax_regions, &dax_region->res); - if (rc) { - dev_dbg(parent, "dax_region resource conflict for %pR\n", - &dax_region->res); + conflict =3D request_resource_conflict(&dax_regions, &dax_region->res); + if (conflict) { + dev_err(parent, + "dax_region: can't claim %pR: address conflict with %s %pR\n", + &dax_region->res, conflict->name, conflict); goto err_res; } =20 --=20 2.47.3