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 6C6D8E7D0AE for ; Thu, 21 Sep 2023 20:36:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232198AbjIUUgY (ORCPT ); Thu, 21 Sep 2023 16:36:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232854AbjIUUfu (ORCPT ); Thu, 21 Sep 2023 16:35:50 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8865180FBA; Thu, 21 Sep 2023 10:36:57 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4979C32794; Thu, 21 Sep 2023 10:24:10 +0000 (UTC) Message-ID: Date: Thu, 21 Sep 2023 12:24:08 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 45/49] media: core: Add bitmap manage bufs array entries Content-Language: en-US, nl To: Benjamin Gaignard , mchehab@kernel.org, tfiga@chromium.org, m.szyprowski@samsung.com, ming.qian@nxp.com, ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de, gregkh@linuxfoundation.org, nicolas.dufresne@collabora.com Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev, kernel@collabora.com References: <20230914133323.198857-1-benjamin.gaignard@collabora.com> <20230914133323.198857-46-benjamin.gaignard@collabora.com> <1142bbb4-b8f1-44ec-962e-9347a231782f@xs4all.nl> <20b6b93e-eef8-3d7b-a3c2-795f220059d4@collabora.com> <470682b4-c14b-4237-bc46-fddfdd085026@xs4all.nl> <31f298ec-6280-d21b-3d8a-c7bf1c9c0c30@collabora.com> From: Hans Verkuil In-Reply-To: <31f298ec-6280-d21b-3d8a-c7bf1c9c0c30@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 21/09/2023 11:28, Benjamin Gaignard wrote: > > Le 20/09/2023 à 16:56, Hans Verkuil a écrit : >> On 20/09/2023 16:30, Benjamin Gaignard wrote: >> >> >>>>>        num_buffers = min_t(unsigned int, num_buffers, >>>>>                    q->max_allowed_buffers - vb2_get_num_buffers(q)); >>>>>    -    first_index = vb2_get_num_buffers(q); >>>>> +    first_index = bitmap_find_next_zero_area(q->bufs_map, q->max_allowed_buffers, >>>>> +                         0, num_buffers, 0); >>>>>          if (first_index >= q->max_allowed_buffers) >>>>>            return 0; >>>>> @@ -675,7 +678,13 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers) >>>>>      struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q, unsigned int index) >>>>>    { >>>>> -    if (index < q->num_buffers) >>>>> +    if (!q->bufs_map || !q->bufs) >>>>> +        return NULL; >>>> I don't think this can ever happen. >>> I got kernel crash without them. >>> I will keep them. >> What is the backtrace? How can this happen? It feels wrong that this can be >> called with a vb2_queue that apparently is not properly initialized. > > I have this log when adding dump_stack() in vb2_get_buffer() if !q->bufs_bitmap: > > [   18.924627] Call trace: > [   18.927090]  dump_backtrace+0x94/0xec > [   18.930787]  show_stack+0x18/0x24 > [   18.934137]  dump_stack_lvl+0x48/0x60 > [   18.937833]  dump_stack+0x18/0x24 > [   18.941166]  __vb2_queue_cancel+0x23c/0x2f0 > [   18.945365]  vb2_core_queue_release+0x24/0x6c > [   18.949740]  vb2_queue_release+0x10/0x1c > [   18.953677]  v4l2_m2m_ctx_release+0x20/0x40 > [   18.957892]  hantro_release+0x20/0x54 > [   18.961584]  v4l2_release+0x74/0xec > [   18.965110]  __fput+0xb4/0x274 > [   18.968205]  __fput_sync+0x50/0x5c > [   18.971626]  __arm64_sys_close+0x38/0x7c > [   18.975562]  invoke_syscall+0x48/0x114 > [   18.979329]  el0_svc_common.constprop.0+0xc0/0xe0 > [   18.984068]  do_el0_svc+0x1c/0x28 > [   18.987402]  el0_svc+0x40/0xe8 > [   18.990470]  el0t_64_sync_handler+0x100/0x12c > [   18.994842]  el0t_64_sync+0x190/0x194 > > This happen at boot time when hantro driver is open and close without other actions. Ah, now I see the problem. q->bufs and q->bufs_map are allocated in vb2_core_create_bufs and vb2_core_reqbufs, but they should be allocated in vb2_queue_init: that's the counterpart of vb2_core_queue_release. With that change you shouldn't have to check for q->bufs/bufs_map anymore. Regards, Hans >     >> >>>>> + >>>>> +    return (bitmap_weight(q->bufs_map, q->max_allowed_buffers) > 0); >>>> How about: >>>> >>>>      return vb2_get_num_buffers(q) > 0; >>> vb2_get_num_buffers is defined in videobuf2-core.c, I'm not sure that >>> an inline function could depend of a module function. >> Not a problem. E.g. v4l2-ctrls.h is full of such static inlines. >> >> Regards, >> >>     Hans >>