From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EAA0C71153 for ; Mon, 28 Aug 2023 17:11:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232681AbjH1RLT (ORCPT ); Mon, 28 Aug 2023 13:11:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232818AbjH1RKr (ORCPT ); Mon, 28 Aug 2023 13:10:47 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA6361BE; Mon, 28 Aug 2023 10:10:26 -0700 (PDT) Received: from pendragon.ideasonboard.com (117.145-247-81.adsl-dyn.isp.belgacom.be [81.247.145.117]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id E03385AA; Mon, 28 Aug 2023 19:08:36 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1693242517; bh=PEDBVlpImfn1ovnvTRgxggBpBos+QgM3i1ko1+4Mrzc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DGg+IqiNJ+0XhQ4Kpx7Q/Rc6vv4DGeYxhmf/Di/bI+P2DWFIE6MK6wQm81AlFy1td 7ir3FLXHsjU/yIs77FxXhx2QAV5iZQDzJnj8BsSXGVy599xKfDI1IYC8Fq0TiHeO9E m/t++PACnq44E2SCVXnLtobsgJwtoKxDYzkppLv4= Date: Mon, 28 Aug 2023 20:10:07 +0300 From: Laurent Pinchart To: Bryan O'Donoghue Cc: rfoss@kernel.org, todor.too@gmail.com, agross@kernel.org, andersson@kernel.org, konrad.dybcio@linaro.org, mchehab@kernel.org, hverkuil-cisco@xs4all.nl, sakari.ailus@linux.intel.com, andrey.konovalov@linaro.org, linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2 3/9] media: qcom: camss: Fix vfe_get() error jump Message-ID: <20230828171007.GX14596@pendragon.ideasonboard.com> References: <20230822200626.1931129-1-bryan.odonoghue@linaro.org> <20230822200626.1931129-4-bryan.odonoghue@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230822200626.1931129-4-bryan.odonoghue@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Bryan, Thank you for the patch. On Tue, Aug 22, 2023 at 09:06:20PM +0100, Bryan O'Donoghue wrote: > Right now it is possible to do a vfe_get() with the internal reference > count at 1. If vfe_check_clock_rates() returns non-zero then we will > leave the reference count as-is and > > run: > - pm_runtime_put_sync() > - vfe->ops->pm_domain_off() > > skip: > - camss_disable_clocks() > > Subsequent vfe_put() calls will when the ref-count is non-zero > unconditionally run: > > - pm_runtime_put_sync() > - vfe->ops->pm_domain_off() > - camss_disable_clocks() > > vfe_get() should not attempt to roll-back on error when the ref-count is > non-zero as the upper layers will still do their own vfe_put() operations. > > vfe_put() will drop the reference count and do the necessary power > domain release, the cleanup jumps in vfe_get() should only be run when > the ref-count is zero. > > [ 50.095796] CPU: 7 PID: 3075 Comm: cam Not tainted 6.3.2+ #80 > [ 50.095798] Hardware name: LENOVO 21BXCTO1WW/21BXCTO1WW, BIOS N3HET82W (1.54 ) 05/26/2023 > [ 50.095799] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > [ 50.095802] pc : refcount_warn_saturate+0xf4/0x148 > [ 50.095804] lr : refcount_warn_saturate+0xf4/0x148 > [ 50.095805] sp : ffff80000c7cb8b0 > [ 50.095806] x29: ffff80000c7cb8b0 x28: ffff16ecc0e3fc10 x27: 0000000000000000 > [ 50.095810] x26: 0000000000000000 x25: 0000000000020802 x24: 0000000000000000 > [ 50.095813] x23: ffff16ecc7360640 x22: 00000000ffffffff x21: 0000000000000005 > [ 50.095815] x20: ffff16ed175f4400 x19: ffffb4d9852942a8 x18: ffffffffffffffff > [ 50.095818] x17: ffffb4d9852d4a48 x16: ffffb4d983da5db8 x15: ffff80000c7cb320 > [ 50.095821] x14: 0000000000000001 x13: 2e656572662d7265 x12: 7466612d65737520 > [ 50.095823] x11: 00000000ffffefff x10: ffffb4d9850cebf0 x9 : ffffb4d9835cf954 > [ 50.095826] x8 : 0000000000017fe8 x7 : c0000000ffffefff x6 : 0000000000057fa8 > [ 50.095829] x5 : ffff16f813fe3d08 x4 : 0000000000000000 x3 : ffff621e8f4d2000 > [ 50.095832] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff16ed32119040 > [ 50.095835] Call trace: > [ 50.095836] refcount_warn_saturate+0xf4/0x148 > [ 50.095838] device_link_put_kref+0x84/0xc8 > [ 50.095843] device_link_del+0x38/0x58 > [ 50.095846] vfe_pm_domain_off+0x3c/0x50 [qcom_camss] > [ 50.095860] vfe_put+0x114/0x140 [qcom_camss] > [ 50.095869] csid_set_power+0x2c8/0x408 [qcom_camss] > [ 50.095878] pipeline_pm_power_one+0x164/0x170 [videodev] > [ 50.095896] pipeline_pm_power+0xc4/0x110 [videodev] > [ 50.095909] v4l2_pipeline_pm_use+0x5c/0xa0 [videodev] > [ 50.095923] v4l2_pipeline_pm_get+0x1c/0x30 [videodev] > [ 50.095937] video_open+0x7c/0x100 [qcom_camss] > [ 50.095945] v4l2_open+0x84/0x130 [videodev] > [ 50.095960] chrdev_open+0xc8/0x250 > [ 50.095964] do_dentry_open+0x1bc/0x498 > [ 50.095966] vfs_open+0x34/0x40 > [ 50.095968] path_openat+0xb44/0xf20 > [ 50.095971] do_filp_open+0xa4/0x160 > [ 50.095974] do_sys_openat2+0xc8/0x188 > [ 50.095975] __arm64_sys_openat+0x6c/0xb8 > [ 50.095977] invoke_syscall+0x50/0x128 > [ 50.095982] el0_svc_common.constprop.0+0x4c/0x100 > [ 50.095985] do_el0_svc+0x40/0xa8 > [ 50.095988] el0_svc+0x2c/0x88 > [ 50.095991] el0t_64_sync_handler+0xf4/0x120 > [ 50.095994] el0t_64_sync+0x190/0x198 > [ 50.095996] ---[ end trace 0000000000000000 ]--- > > Fixes: 779096916dae ("media: camss: vfe: Fix runtime PM imbalance on error") > Cc: stable@vger.kernel.org > Signed-off-by: Bryan O'Donoghue Reviewed-by: Laurent Pinchart > --- > drivers/media/platform/qcom/camss/camss-vfe.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/platform/qcom/camss/camss-vfe.c b/drivers/media/platform/qcom/camss/camss-vfe.c > index dabfd613b2f94..938f373bcd1fd 100644 > --- a/drivers/media/platform/qcom/camss/camss-vfe.c > +++ b/drivers/media/platform/qcom/camss/camss-vfe.c > @@ -611,7 +611,7 @@ int vfe_get(struct vfe_device *vfe) > } else { > ret = vfe_check_clock_rates(vfe); > if (ret < 0) > - goto error_pm_runtime_get; > + goto error_pm_domain; > } > vfe->power_count++; > -- Regards, Laurent Pinchart