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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04A0CC2D0DB for ; Fri, 24 Jan 2020 12:18:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B9371206D4 for ; Fri, 24 Jan 2020 12:18:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731931AbgAXMSK (ORCPT ); Fri, 24 Jan 2020 07:18:10 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:58192 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730037AbgAXMSJ (ORCPT ); Fri, 24 Jan 2020 07:18:09 -0500 Received: from [IPv6:2003:cb:8716:6a00:9da8:f7b8:a96c:6547] (p200300CB87166A009DA8F7B8A96C6547.dip0.t-ipconnect.de [IPv6:2003:cb:8716:6a00:9da8:f7b8:a96c:6547]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: dafna) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id B063F294AB8; Fri, 24 Jan 2020 12:18:04 +0000 (GMT) Subject: Re: [PATCH v5 3/3] media: vimc: use-after-free fix - release vimc in the v4l_device release To: Hans Verkuil , Helen Koike , linux-media@vger.kernel.org Cc: ezequiel@collabora.com, skhan@linuxfoundation.org, kernel@collabora.com, dafna3@gmail.com References: <20200122160148.23686-1-dafna.hirschfeld@collabora.com> <20200122160148.23686-4-dafna.hirschfeld@collabora.com> From: Dafna Hirschfeld Message-ID: <0c618005-aaa1-044e-9ebd-818b4baf9192@collabora.com> Date: Fri, 24 Jan 2020 13:18:02 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 24.01.20 12:31, Hans Verkuil wrote: > On 1/23/20 12:36 PM, Dafna Hirschfeld wrote: >> Hi >> >> On 22.01.20 17:39, Helen Koike wrote: >>> Hi Dafna, >>> >>> Thanks for the patch. >>> >>> On 1/22/20 2:01 PM, Dafna Hirschfeld wrote: >>>> A use-after-free bug occures when unbinding the device while it streams. >>>> The 'struct vimc_ent_device' allocated for the 'Sensor A' is freed >>>> when calling the sensor's 'rm' callback but the freed pointer is >>>> later accessed in the function 'vimc_streamer_pipeline_terminate'. >>>> To fix this bug, move the release callback of the vimc entities >>>> and vimc_device to the release callback of v4l2_device. >>>> The .rm callback of vimc_ent_config is replaced by two callbacks: >>>> >>>> .unregister - this is called upon removing the device and >>>> it unregisters the entity. This is an optional callback since >>>> subdevices don't need to implement it because they are already >>>> unregistered in v4l2_device_unregister. >>>> >>>> .release - this is called from the release callback of v4l2_device >>>> and it frees the entity. >>>> >>>> This ensures that the entities will be released when the last fh >>>> of any of the devices is closed. >>>> >>>> The commands that cause the crash and the KASAN report: >>>> >>>> media-ctl -d platform:vimc -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]' >>>> media-ctl -d platform:vimc -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]' >>>> v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=1920,height=1440 >>>> v4l2-ctl -z platform:vimc -d "Raw Capture 0" -v pixelformat=BA81 >>>> v4l2-ctl --stream-mmap --stream-count=1000 -d /dev/video2 & >>>> sleep 1 >>>> echo -n vimc.0 >/sys/bus/platform/drivers/vimc/unbind >>>> >>>> [  188.417934] BUG: KASAN: use-after-free in vimc_streamer_pipeline_terminate+0x75/0x140 [vimc] >>>> [  188.420182] Read of size 8 at addr ffff8881e9c26008 by task bash/185 >>>> [  188.421800] >>>> [  188.422223] CPU: 0 PID: 185 Comm: bash Not tainted 5.5.0-rc1+ #1 >>>> [  188.423681] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 >>>> [  188.425938] Call Trace: >>>> [  188.426610]  dump_stack+0x75/0xa0 >>>> [  188.427519]  ? vimc_streamer_pipeline_terminate+0x75/0x140 [vimc] >>>> [  188.429057]  print_address_description.constprop.6+0x16/0x220 >>>> [  188.430462]  ? vimc_streamer_pipeline_terminate+0x75/0x140 [vimc] >>>> [  188.431979]  ? vimc_streamer_pipeline_terminate+0x75/0x140 [vimc] >>>> [  188.433455]  __kasan_report.cold.9+0x1a/0x40 >>>> [  188.434518]  ? vimc_streamer_pipeline_terminate+0x75/0x140 [vimc] >>>> [  188.436010]  kasan_report+0xe/0x20 >>>> [  188.436859]  vimc_streamer_pipeline_terminate+0x75/0x140 [vimc] >>>> [  188.438339]  vimc_streamer_s_stream+0x8b/0x3c0 [vimc] >>>> [  188.439576]  vimc_cap_stop_streaming+0x22/0x40 [vimc] >>>> [  188.440863]  __vb2_queue_cancel+0x65/0x560 [videobuf2_common] >>>> [  188.442391]  vb2_core_queue_release+0x19/0x50 [videobuf2_common] >>>> [  188.443974]  vimc_cap_rm+0x10/0x20 [vimc] >>>> [  188.444986]  vimc_rm_subdevs+0x9e/0xe0 [vimc] >>>> [  188.446179]  vimc_remove+0x19/0x70 [vimc] >>>> [  188.447301]  platform_drv_remove+0x2f/0x50 >>>> [  188.448468]  device_release_driver_internal+0x133/0x260 >>>> [  188.449814]  unbind_store+0x121/0x150 >>>> [  188.450726]  kernfs_fop_write+0x142/0x230 >>>> [  188.451724]  ? sysfs_kf_bin_read+0x100/0x100 >>>> [  188.452826]  vfs_write+0xdc/0x230 >>>> [  188.453760]  ksys_write+0xaf/0x140 >>>> [  188.454702]  ? __ia32_sys_read+0x40/0x40 >>>> [  188.455773]  ? __do_page_fault+0x473/0x620 >>>> [  188.456780]  do_syscall_64+0x5e/0x1a0 >>>> [  188.457711]  entry_SYSCALL_64_after_hwframe+0x44/0xa9 >>>> [  188.459079] RIP: 0033:0x7f80f1f13504 >>>> [  188.459969] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 f9 61 0d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89 >>>> d4 55 48 89 f5 53 >>>> [  188.464445] RSP: 002b:00007ffd7e843b58 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 >>>> [  188.466276] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f80f1f13504 >>>> [  188.467999] RDX: 0000000000000006 RSI: 000055ef2eb21b10 RDI: 0000000000000001 >>>> [  188.469708] RBP: 000055ef2eb21b10 R08: 00007f80f1fe68c0 R09: 00007f80f1e26740 >>>> [  188.471407] R10: 000055ef2eade010 R11: 0000000000000246 R12: 00007f80f1fe5760 >>>> [  188.473381] R13: 0000000000000006 R14: 00007f80f1fe0760 R15: 0000000000000006 >>>> [  188.475107] >>>> [  188.475500] Allocated by task 473: >>>> [  188.476351]  save_stack+0x19/0x80 >>>> [  188.477201]  __kasan_kmalloc.constprop.6+0xc1/0xd0 >>>> [  188.478507]  vimc_sen_add+0x36/0x309 [vimc] >>>> [  188.479649]  vimc_probe+0x1e2/0x530 [vimc] >>>> [  188.480776]  platform_drv_probe+0x46/0xa0 >>>> [  188.481829]  really_probe+0x16c/0x520 >>>> [  188.482732]  driver_probe_device+0x114/0x170 >>>> [  188.483783]  device_driver_attach+0x85/0x90 >>>> [  188.484800]  __driver_attach+0xa8/0x190 >>>> [  188.485734]  bus_for_each_dev+0xe4/0x140 >>>> [  188.486702]  bus_add_driver+0x223/0x2d0 >>>> [  188.487715]  driver_register+0xca/0x140 >>>> [  188.488767]  0xffffffffc037003d >>>> [  188.489635]  do_one_initcall+0x86/0x28f >>>> [  188.490702]  do_init_module+0xf8/0x340 >>>> [  188.491773]  load_module+0x3766/0x3a10 >>>> [  188.492811]  __do_sys_finit_module+0x11a/0x1b0 >>>> [  188.494059]  do_syscall_64+0x5e/0x1a0 >>>> [  188.495079]  entry_SYSCALL_64_after_hwframe+0x44/0xa9 >>>> [  188.496481] >>>> [  188.496893] Freed by task 185: >>>> [  188.497670]  save_stack+0x19/0x80 >>>> [  188.498493]  __kasan_slab_free+0x125/0x170 >>>> [  188.499486]  kfree+0x8c/0x230 >>>> [  188.500254]  v4l2_subdev_release+0x64/0x70 [videodev] >>>> [  188.501498]  v4l2_device_release_subdev_node+0x1c/0x30 [videodev] >>>> [  188.502976]  device_release+0x3c/0xd0 >>>> [  188.503867]  kobject_put+0xf4/0x240 >>>> [  188.507802]  vimc_rm_subdevs+0x9e/0xe0 [vimc] >>>> [  188.508846]  vimc_remove+0x19/0x70 [vimc] >>>> [  188.509792]  platform_drv_remove+0x2f/0x50 >>>> [  188.510752]  device_release_driver_internal+0x133/0x260 >>>> [  188.512006]  unbind_store+0x121/0x150 >>>> [  188.512899]  kernfs_fop_write+0x142/0x230 >>>> [  188.513874]  vfs_write+0xdc/0x230 >>>> [  188.514698]  ksys_write+0xaf/0x140 >>>> [  188.515523]  do_syscall_64+0x5e/0x1a0 >>>> [  188.516543]  entry_SYSCALL_64_after_hwframe+0x44/0xa9 >>>> [  188.517710] >>>> [  188.518034] The buggy address belongs to the object at ffff8881e9c26000 >>>> [  188.518034]  which belongs to the cache kmalloc-4k of size 4096 >>>> [  188.520528] The buggy address is located 8 bytes inside of >>>> [  188.520528]  4096-byte region [ffff8881e9c26000, ffff8881e9c27000) >>>> [  188.523015] The buggy address belongs to the page: >>>> [  188.524357] page:ffffea0007a70800 refcount:1 mapcount:0 mapping:ffff8881f6402140 index:0x0 compound_mapcount: 0 >>>> [  188.527058] raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881f6402140 >>>> [  188.528983] raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 >>>> [  188.530883] page dumped because: kasan: bad access detected >>>> [  188.532336] >>>> [  188.532720] Memory state around the buggy address: >>>> [  188.533871]  ffff8881e9c25f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>>> [  188.535631]  ffff8881e9c25f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>>> [  188.537370] >ffff8881e9c26000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>> [  188.538996]                       ^ >>>> [  188.539812]  ffff8881e9c26080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>> [  188.541549]  ffff8881e9c26100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>>> >>>> Signed-off-by: Dafna Hirschfeld >>>> --- >>>>   drivers/media/platform/vimc/vimc-capture.c | 12 ++--- >>>>   drivers/media/platform/vimc/vimc-common.c  |  2 - >>>>   drivers/media/platform/vimc/vimc-common.h  | 25 ++++----- >>>>   drivers/media/platform/vimc/vimc-core.c    | 61 +++++++++++++++------- >>>>   drivers/media/platform/vimc/vimc-debayer.c | 19 ++----- >>>>   drivers/media/platform/vimc/vimc-scaler.c  | 19 ++----- >>>>   drivers/media/platform/vimc/vimc-sensor.c  | 18 ++----- >>>>   7 files changed, 71 insertions(+), 85 deletions(-) >>>> >>>> diff --git a/drivers/media/platform/vimc/vimc-capture.c b/drivers/media/platform/vimc/vimc-capture.c >>>> index 9a78bb7826a8..c5a645f98c66 100644 >>>> --- a/drivers/media/platform/vimc/vimc-capture.c >>>> +++ b/drivers/media/platform/vimc/vimc-capture.c >>>> @@ -325,20 +325,20 @@ static const struct media_entity_operations vimc_cap_mops = { >>>>       .link_validate        = vimc_vdev_link_validate, >>>>   }; >>>>   -static void vimc_cap_release(struct video_device *vdev) >>>> +void vimc_cap_release(struct vimc_ent_device *ved) >>>>   { >>>>       struct vimc_cap_device *vcap = >>>> -        container_of(vdev, struct vimc_cap_device, vdev); >>>> +        container_of(ved, struct vimc_cap_device, ved); >>>>         media_entity_cleanup(vcap->ved.ent); >>>>       kfree(vcap); >>>>   } >>>>   -void vimc_cap_rm(struct vimc_device *vimc, struct vimc_ent_device *ved) >>>> +void vimc_cap_unregister(struct vimc_ent_device *ved) >>>>   { >>>> -    struct vimc_cap_device *vcap; >>>> +    struct vimc_cap_device *vcap = >>>> +        container_of(ved, struct vimc_cap_device, ved); >>>>   -    vcap = container_of(ved, struct vimc_cap_device, ved); >>>>       vb2_queue_release(&vcap->queue); >>>>       video_unregister_device(&vcap->vdev); >>>>   } >>>> @@ -449,7 +449,7 @@ struct vimc_ent_device *vimc_cap_add(struct vimc_device *vimc, >>>>       vdev = &vcap->vdev; >>>>       vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING; >>>>       vdev->entity.ops = &vimc_cap_mops; >>>> -    vdev->release = vimc_cap_release; >>>> +    vdev->release = video_device_release_empty; >>>>       vdev->fops = &vimc_cap_fops; >>>>       vdev->ioctl_ops = &vimc_cap_ioctl_ops; >>>>       vdev->lock = &vcap->lock; >>>> diff --git a/drivers/media/platform/vimc/vimc-common.c b/drivers/media/platform/vimc/vimc-common.c >>>> index 16ce9f3b7c75..c95c17c048f2 100644 >>>> --- a/drivers/media/platform/vimc/vimc-common.c >>>> +++ b/drivers/media/platform/vimc/vimc-common.c >>>> @@ -327,7 +327,6 @@ int vimc_ent_sd_register(struct vimc_ent_device *ved, >>>>                u32 function, >>>>                u16 num_pads, >>>>                struct media_pad *pads, >>>> -             const struct v4l2_subdev_internal_ops *sd_int_ops, >>>>                const struct v4l2_subdev_ops *sd_ops) >>>>   { >>>>       int ret; >>>> @@ -337,7 +336,6 @@ int vimc_ent_sd_register(struct vimc_ent_device *ved, >>>>         /* Initialize the subdev */ >>>>       v4l2_subdev_init(sd, sd_ops); >>>> -    sd->internal_ops = sd_int_ops; >>>>       sd->entity.function = function; >>>>       sd->entity.ops = &vimc_ent_sd_mops; >>>>       sd->owner = THIS_MODULE; >>>> diff --git a/drivers/media/platform/vimc/vimc-common.h b/drivers/media/platform/vimc/vimc-common.h >>>> index 1b6ef7196f3c..616d5a6b0754 100644 >>>> --- a/drivers/media/platform/vimc/vimc-common.h >>>> +++ b/drivers/media/platform/vimc/vimc-common.h >>>> @@ -125,16 +125,18 @@ struct vimc_device { >>>>    * @name            entity name >>>>    * @ved                pointer to vimc_ent_device (a node in the >>>>    *                    topology) >>>> - * @add                subdev add hook - initializes and registers >>>> - *                    subdev called from vimc-core >>>> - * @rm                subdev rm hook - unregisters and frees >>>> - *                    subdev called from vimc-core >>>> + * @add                initializes and registers >>>> + *                    vim entity - called from vimc-core >>>> + * @unregister            unregisters vimc entity - called from vimc-core >>>> + * @release            releases vimc entity - called from the v4l2_dev >>>> + *                    release callback >>>>    */ >>> >>> Did you test the suggestion I gave in last patch? >>> That instead of adding another callback here, to just remove the release functions of the subdevices, >>> and add a check if the release cb isn't null just before calling it. >>> With this, the release functions of the video nodes would be called first. >>> >> I just tested you suggestion, here is the patch: https://gitlab.collabora.com/dafna/linux/commit/f59bc7c6643ce8f88aa33eb5e9f413a1aca99589 >> I get a kasan report: >> >> [   37.736909] BUG: KASAN: use-after-free in v4l2_device_unregister+0xa7/0xf0 [videodev] >> [   37.738110] Read of size 4 at addr ffff8881eb3f00bc by task bash/227 >> ... >> >> What happen is that the function v4l2_device_unregister loops over the subdevices and unregister them: >> >>   /* Unregister subdevs */ >>         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) { >>                 v4l2_device_unregister_subdev(sd); >>                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C) >>                         v4l2_i2c_subdev_unregister(sd); >>                 else if (sd->flags & V4L2_SUBDEV_FL_IS_SPI) >>                         v4l2_spi_subdev_unregister(sd); >>         } >> >> when unregistering the first subdevice it also immediately calls the release callback because no one holds a fh for >> /dev/v4l2-subdev* , but the release cb releases the memory where the 'sd' in the above loop resides, then when >> referencing it in sd->flags it is after it is already freed. > > Urgh. That's a bug in that function. I think the if...else if bit can be moved to > v4l2_subdev_release(). > > I'm surprised that this hasn't been seen before. > I thought that this is not a bug, this happen in vimc only when implementing the release callback of subdevices which we agreed should not be implemented, or I am missing something? Dafna > Regards, > > Hans > >> >> Dafna >> >>> I followed the discussion regarding fhs in media node and video, not that I'm against your changes, >>> but I would like to understand a bit better why the simple fix suggested isn't enough. >>> >>> Thanks >>> Helen >>> >>>>   struct vimc_ent_config { >>>>       const char *name; >>>>       struct vimc_ent_device *(*add)(struct vimc_device *vimc, >>>>                          const char *vcfg_name); >>>> -    void (*rm)(struct vimc_device *vimc, struct vimc_ent_device *ved); >>>> +    void (*unregister)(struct vimc_ent_device *ved); >>>> +    void (*release)(struct vimc_ent_device *ved); >>>>   }; >>>>     /** >>>> @@ -145,22 +147,23 @@ struct vimc_ent_config { >>>>    */ >>>>   bool vimc_is_source(struct media_entity *ent); >>>>   -/* prototypes for vimc_ent_config add and rm hooks */ >>>> +/* prototypes for vimc_ent_config hooks */ >>>>   struct vimc_ent_device *vimc_cap_add(struct vimc_device *vimc, >>>>                        const char *vcfg_name); >>>> -void vimc_cap_rm(struct vimc_device *vimc, struct vimc_ent_device *ved); >>>> +void vimc_cap_unregister(struct vimc_ent_device *ved); >>>> +void vimc_cap_release(struct vimc_ent_device *ved); >>>>     struct vimc_ent_device *vimc_deb_add(struct vimc_device *vimc, >>>>                        const char *vcfg_name); >>>> -void vimc_deb_rm(struct vimc_device *vimc, struct vimc_ent_device *ved); >>>> +void vimc_deb_release(struct vimc_ent_device *ved); >>>>     struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc, >>>>                        const char *vcfg_name); >>>> -void vimc_sca_rm(struct vimc_device *vimc, struct vimc_ent_device *ved); >>>> +void vimc_sca_release(struct vimc_ent_device *ved); >>>>     struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc, >>>>                        const char *vcfg_name); >>>> -void vimc_sen_rm(struct vimc_device *vimc, struct vimc_ent_device *ved); >>>> +void vimc_sen_release(struct vimc_ent_device *ved); >>>>     /** >>>>    * vimc_pix_map_by_index - get vimc_pix_map struct by its index >>>> @@ -195,7 +198,6 @@ const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat); >>>>    * @num_pads:    number of pads to initialize >>>>    * @pads:    the array of pads of the entity, the caller should set the >>>>           flags of the pads >>>> - * @sd_int_ops:    pointer to &struct v4l2_subdev_internal_ops >>>>    * @sd_ops:    pointer to &struct v4l2_subdev_ops. >>>>    * >>>>    * Helper function initialize and register the struct vimc_ent_device and struct >>>> @@ -208,7 +210,6 @@ int vimc_ent_sd_register(struct vimc_ent_device *ved, >>>>                u32 function, >>>>                u16 num_pads, >>>>                struct media_pad *pads, >>>> -             const struct v4l2_subdev_internal_ops *sd_int_ops, >>>>                const struct v4l2_subdev_ops *sd_ops); >>>>     /** >>>> diff --git a/drivers/media/platform/vimc/vimc-core.c b/drivers/media/platform/vimc/vimc-core.c >>>> index 1c55e0382f09..306f9c293628 100644 >>>> --- a/drivers/media/platform/vimc/vimc-core.c >>>> +++ b/drivers/media/platform/vimc/vimc-core.c >>>> @@ -48,48 +48,51 @@ static struct vimc_ent_config ent_config[] = { >>>>       { >>>>           .name = "Sensor A", >>>>           .add = vimc_sen_add, >>>> -        .rm = vimc_sen_rm, >>>> +        .release = vimc_sen_release, >>>>       }, >>>>       { >>>>           .name = "Sensor B", >>>>           .add = vimc_sen_add, >>>> -        .rm = vimc_sen_rm, >>>> +        .release = vimc_sen_release, >>>>       }, >>>>       { >>>>           .name = "Debayer A", >>>>           .add = vimc_deb_add, >>>> -        .rm = vimc_deb_rm, >>>> +        .release = vimc_deb_release, >>>>       }, >>>>       { >>>>           .name = "Debayer B", >>>>           .add = vimc_deb_add, >>>> -        .rm = vimc_deb_rm, >>>> +        .release = vimc_deb_release, >>>>       }, >>>>       { >>>>           .name = "Raw Capture 0", >>>>           .add = vimc_cap_add, >>>> -        .rm = vimc_cap_rm, >>>> +        .unregister = vimc_cap_unregister, >>>> +        .release = vimc_cap_release, >>>>       }, >>>>       { >>>>           .name = "Raw Capture 1", >>>>           .add = vimc_cap_add, >>>> -        .rm = vimc_cap_rm, >>>> +        .unregister = vimc_cap_unregister, >>>> +        .release = vimc_cap_release, >>>>       }, >>>>       { >>>>           /* TODO: change this to vimc-input when it is implemented */ >>>>           .name = "RGB/YUV Input", >>>>           .add = vimc_sen_add, >>>> -        .rm = vimc_sen_rm, >>>> +        .release = vimc_sen_release, >>>>       }, >>>>       { >>>>           .name = "Scaler", >>>>           .add = vimc_sca_add, >>>> -        .rm = vimc_sca_rm, >>>> +        .release = vimc_sca_release, >>>>       }, >>>>       { >>>>           .name = "RGB/YUV Capture", >>>>           .add = vimc_cap_add, >>>> -        .rm = vimc_cap_rm, >>>> +        .unregister = vimc_cap_unregister, >>>> +        .release = vimc_cap_release, >>>>       }, >>>>   }; >>>>   @@ -175,13 +178,33 @@ static int vimc_add_subdevs(struct vimc_device *vimc) >>>>       return 0; >>>>   } >>>>   -static void vimc_rm_subdevs(struct vimc_device *vimc) >>>> +static void vimc_release_subdevs(struct vimc_device *vimc) >>>>   { >>>>       unsigned int i; >>>>         for (i = 0; i < vimc->pipe_cfg->num_ents; i++) >>>>           if (vimc->ent_devs[i]) >>>> -            vimc->pipe_cfg->ents[i].rm(vimc, vimc->ent_devs[i]); >>>> +            vimc->pipe_cfg->ents[i].release(vimc->ent_devs[i]); >>>> +} >>>> + >>>> +static void vimc_unregister_subdevs(struct vimc_device *vimc) >>>> +{ >>>> +    unsigned int i; >>>> + >>>> +    for (i = 0; i < vimc->pipe_cfg->num_ents; i++) >>>> +        if (vimc->ent_devs[i] && vimc->pipe_cfg->ents[i].unregister) >>>> +            vimc->pipe_cfg->ents[i].unregister(vimc->ent_devs[i]); >>>> +} >>>> + >>>> +static void vimc_v4l2_dev_release(struct v4l2_device *v4l2_dev) >>>> +{ >>>> +    struct vimc_device *vimc = >>>> +        container_of(v4l2_dev, struct vimc_device, v4l2_dev); >>>> + >>>> +    vimc_release_subdevs(vimc); >>>> +    media_device_cleanup(&vimc->mdev); >>>> +    kfree(vimc->ent_devs); >>>> +    kfree(vimc); >>>>   } >>>>     static int vimc_register_devices(struct vimc_device *vimc) >>>> @@ -195,7 +218,6 @@ static int vimc_register_devices(struct vimc_device *vimc) >>>>               "v4l2 device register failed (err=%d)\n", ret); >>>>           return ret; >>>>       } >>>> - >>>>       /* allocate ent_devs */ >>>>       vimc->ent_devs = kcalloc(vimc->pipe_cfg->num_ents, >>>>                    sizeof(*vimc->ent_devs), GFP_KERNEL); >>>> @@ -236,9 +258,9 @@ static int vimc_register_devices(struct vimc_device *vimc) >>>>     err_mdev_unregister: >>>>       media_device_unregister(&vimc->mdev); >>>> -    media_device_cleanup(&vimc->mdev); >>>>   err_rm_subdevs: >>>> -    vimc_rm_subdevs(vimc); >>>> +    vimc_unregister_subdevs(vimc); >>>> +    vimc_release_subdevs(vimc); >>>>       kfree(vimc->ent_devs); >>>>   err_v4l2_unregister: >>>>       v4l2_device_unregister(&vimc->v4l2_dev); >>>> @@ -248,11 +270,9 @@ static int vimc_register_devices(struct vimc_device *vimc) >>>>     static void vimc_unregister(struct vimc_device *vimc) >>>>   { >>>> +    vimc_unregister_subdevs(vimc); >>>>       media_device_unregister(&vimc->mdev); >>>> -    media_device_cleanup(&vimc->mdev); >>>>       v4l2_device_unregister(&vimc->v4l2_dev); >>>> -    kfree(vimc->ent_devs); >>>> -    kfree(vimc); >>>>   } >>>>     static int vimc_probe(struct platform_device *pdev) >>>> @@ -285,7 +305,12 @@ static int vimc_probe(struct platform_device *pdev) >>>>           kfree(vimc); >>>>           return ret; >>>>       } >>>> +    /* >>>> +     * the release cb is set only after successful registration. >>>> +     * if the registration fails, we release directly from probe >>>> +     */ >>>>   +    vimc->v4l2_dev.release = vimc_v4l2_dev_release; >>>>       platform_set_drvdata(pdev, vimc); >>>>       return 0; >>>>   } >>>> @@ -296,8 +321,8 @@ static int vimc_remove(struct platform_device *pdev) >>>>         dev_dbg(&pdev->dev, "remove"); >>>>   -    vimc_rm_subdevs(vimc); >>>>       vimc_unregister(vimc); >>>> +    v4l2_device_put(&vimc->v4l2_dev); >>>>         return 0; >>>>   } >>>> diff --git a/drivers/media/platform/vimc/vimc-debayer.c b/drivers/media/platform/vimc/vimc-debayer.c >>>> index 34b98b235880..baf6bf9f65b5 100644 >>>> --- a/drivers/media/platform/vimc/vimc-debayer.c >>>> +++ b/drivers/media/platform/vimc/vimc-debayer.c >>>> @@ -494,28 +494,16 @@ static const struct v4l2_ctrl_ops vimc_deb_ctrl_ops = { >>>>       .s_ctrl = vimc_deb_s_ctrl, >>>>   }; >>>>   -static void vimc_deb_release(struct v4l2_subdev *sd) >>>> +void vimc_deb_release(struct vimc_ent_device *ved) >>>>   { >>>>       struct vimc_deb_device *vdeb = >>>> -                container_of(sd, struct vimc_deb_device, sd); >>>> +        container_of(ved, struct vimc_deb_device, ved); >>>>         v4l2_ctrl_handler_free(&vdeb->hdl); >>>>       media_entity_cleanup(vdeb->ved.ent); >>>>       kfree(vdeb); >>>>   } >>>>   -static const struct v4l2_subdev_internal_ops vimc_deb_int_ops = { >>>> -    .release = vimc_deb_release, >>>> -}; >>>> - >>>> -void vimc_deb_rm(struct vimc_device *vimc, struct vimc_ent_device *ved) >>>> -{ >>>> -    struct vimc_deb_device *vdeb; >>>> - >>>> -    vdeb = container_of(ved, struct vimc_deb_device, ved); >>>> -    v4l2_device_unregister_subdev(&vdeb->sd); >>>> -} >>>> - >>>>   static const struct v4l2_ctrl_config vimc_deb_ctrl_class = { >>>>       .flags = V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY, >>>>       .id = VIMC_CID_VIMC_CLASS, >>>> @@ -563,8 +551,7 @@ struct vimc_ent_device *vimc_deb_add(struct vimc_device *vimc, >>>>       ret = vimc_ent_sd_register(&vdeb->ved, &vdeb->sd, v4l2_dev, >>>>                      vcfg_name, >>>>                      MEDIA_ENT_F_PROC_VIDEO_PIXEL_ENC_CONV, 2, >>>> -                   vdeb->pads, >>>> -                   &vimc_deb_int_ops, &vimc_deb_ops); >>>> +                   vdeb->pads, &vimc_deb_ops); >>>>       if (ret) >>>>           goto err_free_hdl; >>>>   diff --git a/drivers/media/platform/vimc/vimc-scaler.c b/drivers/media/platform/vimc/vimc-scaler.c >>>> index cb2dc24c3e59..7521439747c5 100644 >>>> --- a/drivers/media/platform/vimc/vimc-scaler.c >>>> +++ b/drivers/media/platform/vimc/vimc-scaler.c >>>> @@ -464,27 +464,15 @@ static void *vimc_sca_process_frame(struct vimc_ent_device *ved, >>>>       return vsca->src_frame; >>>>   }; >>>>   -static void vimc_sca_release(struct v4l2_subdev *sd) >>>> +void vimc_sca_release(struct vimc_ent_device *ved) >>>>   { >>>>       struct vimc_sca_device *vsca = >>>> -                container_of(sd, struct vimc_sca_device, sd); >>>> +        container_of(ved, struct vimc_sca_device, ved); >>>>         media_entity_cleanup(vsca->ved.ent); >>>>       kfree(vsca); >>>>   } >>>>   -static const struct v4l2_subdev_internal_ops vimc_sca_int_ops = { >>>> -    .release = vimc_sca_release, >>>> -}; >>>> - >>>> -void vimc_sca_rm(struct vimc_device *vimc, struct vimc_ent_device *ved) >>>> -{ >>>> -    struct vimc_sca_device *vsca; >>>> - >>>> -    vsca = container_of(ved, struct vimc_sca_device, ved); >>>> -    v4l2_device_unregister_subdev(&vsca->sd); >>>> -} >>>> - >>>>   struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc, >>>>                        const char *vcfg_name) >>>>   { >>>> @@ -504,8 +492,7 @@ struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc, >>>>       ret = vimc_ent_sd_register(&vsca->ved, &vsca->sd, v4l2_dev, >>>>                      vcfg_name, >>>>                      MEDIA_ENT_F_PROC_VIDEO_SCALER, 2, >>>> -                   vsca->pads, >>>> -                   &vimc_sca_int_ops, &vimc_sca_ops); >>>> +                   vsca->pads, &vimc_sca_ops); >>>>       if (ret) { >>>>           kfree(vsca); >>>>           return NULL; >>>> diff --git a/drivers/media/platform/vimc/vimc-sensor.c b/drivers/media/platform/vimc/vimc-sensor.c >>>> index 9788fe291193..92daee58209e 100644 >>>> --- a/drivers/media/platform/vimc/vimc-sensor.c >>>> +++ b/drivers/media/platform/vimc/vimc-sensor.c >>>> @@ -279,10 +279,10 @@ static const struct v4l2_ctrl_ops vimc_sen_ctrl_ops = { >>>>       .s_ctrl = vimc_sen_s_ctrl, >>>>   }; >>>>   -static void vimc_sen_release(struct v4l2_subdev *sd) >>>> +void vimc_sen_release(struct vimc_ent_device *ved) >>>>   { >>>>       struct vimc_sen_device *vsen = >>>> -                container_of(sd, struct vimc_sen_device, sd); >>>> +        container_of(ved, struct vimc_sen_device, ved); >>>>         v4l2_ctrl_handler_free(&vsen->hdl); >>>>       tpg_free(&vsen->tpg); >>>> @@ -290,18 +290,6 @@ static void vimc_sen_release(struct v4l2_subdev *sd) >>>>       kfree(vsen); >>>>   } >>>>   -static const struct v4l2_subdev_internal_ops vimc_sen_int_ops = { >>>> -    .release = vimc_sen_release, >>>> -}; >>>> - >>>> -void vimc_sen_rm(struct vimc_device *vimc, struct vimc_ent_device *ved) >>>> -{ >>>> -    struct vimc_sen_device *vsen; >>>> - >>>> -    vsen = container_of(ved, struct vimc_sen_device, ved); >>>> -    v4l2_device_unregister_subdev(&vsen->sd); >>>> -} >>>> - >>>>   /* Image Processing Controls */ >>>>   static const struct v4l2_ctrl_config vimc_sen_ctrl_class = { >>>>       .flags = V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY, >>>> @@ -365,7 +353,7 @@ struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc, >>>>       ret = vimc_ent_sd_register(&vsen->ved, &vsen->sd, v4l2_dev, >>>>                      vcfg_name, >>>>                      MEDIA_ENT_F_CAM_SENSOR, 1, &vsen->pad, >>>> -                   &vimc_sen_int_ops, &vimc_sen_ops); >>>> +                   &vimc_sen_ops); >>>>       if (ret) >>>>           goto err_free_tpg; >>>> >