From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752529AbeB0JJS (ORCPT ); Tue, 27 Feb 2018 04:09:18 -0500 Received: from mail.bootlin.com ([62.4.15.54]:46625 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752096AbeB0JJQ (ORCPT ); Tue, 27 Feb 2018 04:09:16 -0500 Date: Tue, 27 Feb 2018 10:09:13 +0100 From: Maxime Ripard To: Philipp Rossak Cc: wens@csie.org, a.zummo@towertech.it, alexandre.belloni@bootlin.com, mturquette@baylibre.com, sboyd@codeaurora.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com, linux-rtc@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v4] rtc: ac100: Fix ac100 determine rate bug Message-ID: <20180227090913.3vb6yudd4nh2wlyh@flea> References: <20180226211901.9805-1-embed3d@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="f3wecsvhqugikgzn" Content-Disposition: inline In-Reply-To: <20180226211901.9805-1-embed3d@gmail.com> User-Agent: NeoMutt/20180223 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --f3wecsvhqugikgzn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 26, 2018 at 10:19:01PM +0100, Philipp Rossak wrote: > This patch fixes a bug, that prevents the Allwinner A83T and the A80 > from a successful boot. >=20 > The bug is there since v4.16-rc1 and appeared after the clk branch was > merged. >=20 > You can find the shortend trace below: >=20 > Unable to handle kernel NULL pointer dereference at virtual address > 00000000 > pgd =3D (ptrval) > [00000000] *pgd=3D00000000 > Internal error: Oops: 5 [#1] SMP ARM > Modules linked in: > CPU: 0 PID: 49 Comm: kworker/0:1 Not tainted 4.15.0-10190-gb89e32ccd1be #2 > Hardware name: Allwinner sun8i Family > Workqueue: events deferred_probe_work_func > PC is at clk_hw_get_rate+0x0/0x34 > LR is at ac100_clkout_determine_rate+0x48/0x19c >=20 > [ ... ] >=20 > (clk_hw_get_rate) from (ac100_clkout_determine_rate+0x48/0x19c) > (ac100_clkout_determine_rate) from (clk_core_set_rate_nolock+0x3c/0x1a0) > (clk_core_set_rate_nolock) from (clk_set_rate+0x30/0x88) > (clk_set_rate) from (of_clk_set_defaults+0x200/0x364) > (of_clk_set_defaults) from (platform_drv_probe+0x18/0xb0) >=20 > To fix that bug, we first check if the return of the > clk_hw_get_parent_by_index is non zero. If it is zero we skip that > clock parent. >=20 > The BUG report could be found here: https://lkml.org/lkml/2018/2/10/198 >=20 > Fixes: 04940631b8d2 ("rtc: ac100: Add clk output support") >=20 > Signed-off-by: Philipp Rossak Acked-by: Maxime Ripard Thanks! Maxime --=20 Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com --f3wecsvhqugikgzn Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE0VqZU19dR2zEVaqr0rTAlCFNr3QFAlqVIDgACgkQ0rTAlCFN r3SKUBAAmcXMlygQJbkcmBF6rYnTivNolCp0SWBSagp/4wBeR4LMQZr51PVntfS8 NoUaJgQGBXV3Wt1wwO18KSzeK8QzA/ngbBl+W+uPERXij5VxR+huYYALvj82aK+X i/se2qemdHkbpPOxtAgglYHv2WjBk2y+cCTLOrzRMaeyUldUfSbPl/ddMiC8e19e LrM326W4/F+tva8DE8dGy6ojyg023b6NfM/VKQGGGA9iVOJUIkNV67rTKs5npiK8 teSqME/NdORF43ZAzF0qkGZqvBLAOGZXCFRpRb7QDnTO6NpyfCiOHIj4rkb9XlpX OI4DkqfsMeve6pyYYperLoVA3bhIj8T3qzjVXgRdVKjG+Cz4afwQ9gsP5WIKr9wT VlzhTSdBx9c64ZuG+6bphH2cVUVUdtWTJVSd+jx1nGJeaOiP+1Pv/nB8A/wMnM0+ oucA+oxQhWPVnIczlWyZ0Scs7HmaR9r0ZkWROSX+WtlQn5N1gU0fpFsnyfiFh47o XF2sCDbAXtC8KckNI39vUM5uYTsZlrhgA+g5uzYRrlFBJnvV6Ds/nHuDu1ZNc6nK 9Le7Y0TkceLZNfmGZX0v19clFt1d73c8cnbHwTVB0kz/hmffKEzoX8A7IJOjWv5w bCRiIZL9eODMX2oaBby0dvEgn/5eUgm+zZHfBgrxgl2n2+BuIUQ= =4Khs -----END PGP SIGNATURE----- --f3wecsvhqugikgzn--