From nobody Tue Sep 29 18:55:39 2026 Received: from mail-pj1-f49.google.com (mail-pj1-f49.google.com [209.85.216.49]) (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 093A73D8903 for ; Thu, 20 Aug 2026 09:57:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.49 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787219848; cv=none; b=Gsoshw3fNcgEomr4dPRR4oJJ5VK5wQSvv0xmP+8fsy9Af2uXwf2H/CM/dKHp49HmOsLmaPtxbnfrf73S6V2fmIXcPxCgsyftx5rIUAGNOx316K/GmRR6XaaCeI+4uRUcAW5D4LOlq5GyzY72ndfd4EwxEa4cma4Es7cfJYlYoF0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787219848; c=relaxed/simple; bh=WKBvEnsdTJBmKCzNv2bAc+m7P5UpoFHCP17W9kDPtbo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Cw6axBRGUDTYSjYM69XwSOACzOKaISd4dmd+NtIrHOMVTQOxYeAq9InL6MOy7CRd4ZV1Ba/gGapXXQdGeMXx5+O33ahHpO5xa80LC3lrjaV//A8ji/0rmO78hhYqRiQM9sRUuzbtcrLO3Zaap4IRJK/0y1hbko3jUSjDgcslhpk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=JfR+Udtv; arc=none smtp.client-ip=209.85.216.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="JfR+Udtv" Received: by mail-pj1-f49.google.com with SMTP id 98e67ed59e1d1-38fdeaed181so2876860a91.1 for ; Thu, 20 Aug 2026 02:57:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1787219845; x=1787824645; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=VKxa3YviLN5cCzfebqP3NL9+RZDJhxjogBm8ItS5b/Y=; b=JfR+UdtvSz2DlePMzDJShoUZQniEbULmX/CoFPL40m1agrGRbjwwUuj0O9z+Wsx0OW iIxAPxD9DtDl8SIyRMuTl7mgOGX77lV91cO533u/jtopsWo+PRCJ5ZR74cbPMDXsPes6 F3d9ld4bYoPpktMb/aIGQolzXHixpQNbFvDyU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787219845; x=1787824645; h=content-transfer-encoding:mime-version: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=VKxa3YviLN5cCzfebqP3NL9+RZDJhxjogBm8ItS5b/Y=; b=lZpknDLxkU8dcsThxIh30WdHusNTKpZtIicvlF/Ag75hIARckNj7JkErCirXTQfFc9 5XIbN3UIi1Ua+Oo4XW3+frrx6iXGYmZTAFsTTpqjsiTYwf52MR6mwNeN+XnvyPwNDxNd Gx3/nGXgNZUYl85Oc0sUcasn+Te9U1YRNb9+akHi4cbcQTGABnde40pZo2mUKLM2Lv8y H8kiAL3SZi76alXNA15uTAGfkrA4FEumpzloXV6GiIgriurnd2DyGC/baGDgr99ifpxk p+idAuNpVcUPpSskcVINlpil5X6CBvlemBR2JtdHAx0a3guQDRkbac0jT1EGfesXNU+c +QSg== X-Forwarded-Encrypted: i=1; AHgh+Rq9X9wotXFx9i/1SSKl2QnqQEicBp09DuXpbMoCUhffR0V8x0vvQ+KOjGVG4PhI4PYZFwGof7hq8FjeRvE=@vger.kernel.org X-Gm-Message-State: AFuF++lol2aFLa1urAb9mc7WzJzQAvdYhuZK817jgI3mOtDhTTWuQu3S Jb7Zk8cMtqg0nwo4NKxu+sUDCHRONYaqQuuVdxzHJeM/R0WHp5PZBfkylxaCc0FIFFDwT73LDXW JZIZgLQ== X-Gm-Gg: AR+sD10uTqK6pNB1MEogqDZ6RJ5631Vz6v5l1LvIAMPJLbRs+VJESfmyBsAY3dhVon5 AnQPNmxIsuN/ULfDX0I6tIgtdmIk3rcvKb5XUZGBiE9nvYlX6oa1qnc3b0aMyAOFALXX9N7p5t8 gMv4Rqo45JK3FPi3lr+W9Qx8MHTgpm/WTzh1zNFvg6lMrHwTqcK1gM47bAhEeDhvQJ6SLSjFCoY 9upN52Zh+bEW604sjnTcLAZWdW6zuTxt6BKL0dCpTBIGj5vUvCAWiI/olSPzB/eB8wplMWR0+6N GUjYAnal/qJbkpY/1TebURkkvF54qOVxf4gU2QJWlOUkjs5JFABrJJOjpe5XjaMyHL7na5Cscja C6BPEhCXgpvSEgH8VTVIa+Yew9x2vSsno8IwPy3kgTFiIjDTB3nG+9NDYK2rSUXiiaOWoTdHsc9 AMev6t+J/XNNpGZpC2rT0+i5/oobZcSBLoDRYXjkZ1SQ/tFZ8NNAftnCjCFqcxLZ5ntB1b1sW21 5Qj93DuePqIW6mJVCw+qPTLfp1TiePtaeG1BfMfo4JTLow= X-Received: by 2002:a17:90b:2f8b:b0:38f:57f0:1f5d with SMTP id 98e67ed59e1d1-395810d73e6mr22203640a91.15.1787219844897; Thu, 20 Aug 2026 02:57:24 -0700 (PDT) Received: from wenst-7875.tpe.corp.google.com ([2a00:79e0:201d:8:f586:a29c:c825:e01b]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3957fbbb8d5sm6602675a91.14.2026.08.20.02.57.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Aug 2026 02:57:24 -0700 (PDT) From: Chen-Yu Tsai To: Mathias Nyman , Greg Kroah-Hartman Cc: Chen-Yu Tsai , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Niklas Neronin Subject: [PATCH] usb: xhci: Fix HCS_ERST_MAX conversion Date: Thu, 20 Aug 2026 17:57:13 +0800 Message-ID: <20260820095714.1865096-1-wenst@chromium.org> X-Mailer: git-send-email 2.55.0.860.g4b6b3295ed-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This partially reverts commit 6d45e9556d4a11b726e897d86e095b96db4550d8. HCS_ERST_MAX holds power of 2 value for maximum number of segments. In the culprit commit, this was incorrectly converted to "shift up 2". On hardware where this field is zero, this results in xhci_alloc_erst() calling dma_alloc_coherent() with size =3D 0, leading to a horrible splat and non-usable XHCI. Revert the shift-up-2 to the BIT() macro. Fixes: 6d45e9556d4a ("usb: xhci: standardize multi bit-field macros") Cc: Niklas Neronin Signed-off-by: Chen-Yu Tsai --- This immediately fixes XHCI for me. This was observed on next-20260818 and next-20260819. --- drivers/usb/host/xhci-mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 7a21ac81f9c8..af8d4b74c4ba 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -2301,7 +2301,7 @@ xhci_alloc_interrupter(struct xhci_hcd *xhci, unsigne= d int segs, gfp_t flags) if (!segs) segs =3D ERST_DEFAULT_SEGS; =20 - max_segs =3D FIELD_GET(HCS_ERST_MAX, xhci->hcs_params2) << 2; + max_segs =3D BIT(FIELD_GET(HCS_ERST_MAX, xhci->hcs_params2)); segs =3D min(segs, max_segs); =20 ir =3D kzalloc_node(sizeof(*ir), flags, dev_to_node(dev)); --=20 2.55.0.860.g4b6b3295ed-goog