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From: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
To: linux-media@vger.kernel.org
Cc: dafna.hirschfeld@collabora.com, helen.koike@collabora.com,
	skhan@linuxfoundation.org, hverkuil@xs4all.nl,
	kernel@collabora.com, dafna3@gmail.com
Subject: [PATCH v4 2/2] media: vimc: upon streaming, check that the pipeline starts with a source entity
Date: Thu, 24 Oct 2019 11:35:25 +0200	[thread overview]
Message-ID: <20191024093525.10059-3-dafna.hirschfeld@collabora.com> (raw)
In-Reply-To: <20191024093525.10059-1-dafna.hirschfeld@collabora.com>

Userspace can disable links and create pipelines that
do not start with a source entity. Trying to stream
from such a pipeline should fail with -EPIPE
currently this is not handled and cause kernel crash.

Reproducing the crash:
media-ctl -d0 -l "5:1->21:0[0]" -v
v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=1920,height=1440
v4l2-ctl --stream-mmap --stream-count=100 -d /dev/video2

Panic message:
[   39.078841][  T248] BUG: kernel NULL pointer dereference, address: 0000000000000000
[   39.079338][  T248] #PF: supervisor read access in kernel mode
[   39.079704][  T248] #PF: error_code(0x0000) - not-present page
[   39.080071][  T248] PGD 0 P4D 0
[   39.080279][  T248] Oops: 0000 [#1] SMP PTI
[   39.080546][  T248] CPU: 0 PID: 248 Comm: vimc-streamer t Not tainted 5.4.0-rc1+ #17
[   39.081030][  T248] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
[   39.081779][  T248] RIP: 0010:vimc_sca_process_frame+0xdb/0x210 [vimc]
[   39.082191][  T248] Code: 44 8d 0c 28 8b 93 a4 01 00 00 48 8b 8b 98 01 00 00 85 d2 74 40 48 8b 74 24 10 8d 7a ff 4c 01 c9 31 d2 4c 01 fe eb 03 4c 89 c2 <44> 0f b6 04 16 44 88 04 11 4c 8d 42 01 48 39 fa 75 eb 8b 93 a4 01
[   39.083436][  T248] RSP: 0018:ffffb15a005abe90 EFLAGS: 00010246
[   39.083808][  T248] RAX: 0000000000000000 RBX: ffffa3fdc46d2e00 RCX: ffffb15a02579000
[   39.084298][  T248] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
[   39.084792][  T248] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[   39.085280][  T248] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[   39.085770][  T248] R13: ffffa3fdc46d2ee0 R14: 0000000000000000 R15: 0000000000000000
[   39.086258][  T248] FS:  0000000000000000(0000) GS:ffffa3fdc7800000(0000) knlGS:0000000000000000
[   39.086806][  T248] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   39.087217][  T248] CR2: 0000000000000000 CR3: 0000000003c92005 CR4: 0000000000360ef0
[   39.087706][  T248] Call Trace:
[   39.087909][  T248]  ? vimc_streamer_pipeline_terminate+0x90/0x90 [vimc]
[   39.088318][  T248]  vimc_streamer_thread+0x7c/0xe0 [vimc]
[   39.088663][  T248]  kthread+0x10d/0x130
[   39.088919][  T248]  ? kthread_park+0x80/0x80
[   39.089205][  T248]  ret_from_fork+0x35/0x40
[   39.089475][  T248] Modules linked in: vimc videobuf2_vmalloc videobuf2_memops v4l2_tpg videobuf2_v4l2 videobuf2_common videodev mc
[   39.090208][  T248] CR2: 0000000000000000
[   39.090463][  T248] ---[ end trace 697650fefbf78bee ]---
[   39.090796][  T248] RIP: 0010:vimc_sca_process_frame+0xdb/0x210 [vimc]
[   39.091209][  T248] Code: 44 8d 0c 28 8b 93 a4 01 00 00 48 8b 8b 98 01 00 00 85 d2 74 40 48 8b 74 24 10 8d 7a ff 4c 01 c9 31 d2 4c 01 fe eb 03 4c 89 c2 <44> 0f b6 04 16 44 88 04 11 4c 8d 42 01 48 39 fa 75 eb 8b 93 a4 01
[   39.092417][  T248] RSP: 0018:ffffb15a005abe90 EFLAGS: 00010246
[   39.092789][  T248] RAX: 0000000000000000 RBX: ffffa3fdc46d2e00 RCX: ffffb15a02579000
[   39.093278][  T248] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
[   39.093766][  T248] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[   39.094254][  T248] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[   39.094742][  T248] R13: ffffa3fdc46d2ee0 R14: 0000000000000000 R15: 0000000000000000
[   39.095309][  T248] FS:  0000000000000000(0000) GS:ffffa3fdc7800000(0000) knlGS:0000000000000000
[   39.095974][  T248] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   39.096372][  T248] CR2: 0000000000000000 CR3: 0000000003c92005 CR4: 0000000000360ef0

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
---
 drivers/media/platform/vimc/vimc-common.c   | 10 +++++++
 drivers/media/platform/vimc/vimc-common.h   |  5 ++++
 drivers/media/platform/vimc/vimc-streamer.c | 29 ++++++++++++++-------
 3 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/drivers/media/platform/vimc/vimc-common.c b/drivers/media/platform/vimc/vimc-common.c
index a3120f4f7a90..e8ad3199ffbf 100644
--- a/drivers/media/platform/vimc/vimc-common.c
+++ b/drivers/media/platform/vimc/vimc-common.c
@@ -164,6 +164,16 @@ static const struct vimc_pix_map vimc_pix_map_list[] = {
 	},
 };
 
+bool vimc_is_source(struct media_entity *ent)
+{
+	unsigned int i;
+
+	for (i = 0; i < ent->num_pads; i++)
+		if (ent->pads[i].flags & MEDIA_PAD_FL_SINK)
+			return false;
+	return true;
+}
+
 const struct vimc_pix_map *vimc_pix_map_by_index(unsigned int i)
 {
 	if (i >= ARRAY_SIZE(vimc_pix_map_list))
diff --git a/drivers/media/platform/vimc/vimc-common.h b/drivers/media/platform/vimc/vimc-common.h
index 8349e3c68a49..112574bc3089 100644
--- a/drivers/media/platform/vimc/vimc-common.h
+++ b/drivers/media/platform/vimc/vimc-common.h
@@ -154,6 +154,11 @@ struct vimc_ent_config {
 	void (*rm)(struct vimc_device *vimc, struct vimc_ent_device *ved);
 };
 
+/**
+ * vimc_is_source - returns true iff the entity has only source pads
+ */
+bool vimc_is_source(struct media_entity *ent);
+
 /* prototypes for vimc_ent_config add and rm hooks */
 struct vimc_ent_device *vimc_cap_add(struct vimc_device *vimc,
 				     const char *vcfg_name);
diff --git a/drivers/media/platform/vimc/vimc-streamer.c b/drivers/media/platform/vimc/vimc-streamer.c
index 37150c919fcb..e7554598b34f 100644
--- a/drivers/media/platform/vimc/vimc-streamer.c
+++ b/drivers/media/platform/vimc/vimc-streamer.c
@@ -87,8 +87,10 @@ static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 	stream->pipe_size = 0;
 	while (stream->pipe_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
 		if (!ved) {
-			vimc_streamer_pipeline_terminate(stream);
-			return -EINVAL;
+			pr_err("%s: could not get vimc pointer of entity",
+			       __func__);
+			ret = -EINVAL;
+			break;
 		}
 		stream->ved_pipeline[stream->pipe_size++] = ved;
 
@@ -96,17 +98,25 @@ static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 			sd = media_entity_to_v4l2_subdev(ved->ent);
 			ret = v4l2_subdev_call(sd, video, s_stream, 1);
 			if (ret && ret != -ENOIOCTLCMD) {
-				dev_err(ved->dev, "subdev_call error %s\n",
-				       ved->ent->name);
-				vimc_streamer_pipeline_terminate(stream);
-				return ret;
+				dev_err(ved->dev, "s_stream of '%s' failed (%d)\n",
+					ved->ent->name, ret);
+				break;
 			}
 		}
 
 		entity = vimc_get_source_entity(ved->ent);
-		/* Check if the end of the pipeline was reached*/
-		if (!entity)
+		/* Check if the end of the pipeline was reached */
+		if (!entity) {
+			/* the first entity of the pipe should be source only */
+			if (!vimc_is_source(ved->ent)) {
+				dev_err(ved->dev,
+					"first entity in the pipe '%s' is not a source\n",
+					ved->ent->name);
+				ret = -EPIPE;
+				break;
+			}
 			return 0;
+		}
 
 		/* Get the next device in the pipeline */
 		if (is_media_entity_v4l2_subdev(entity)) {
@@ -119,9 +129,8 @@ static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 			ved = video_get_drvdata(vdev);
 		}
 	}
-
 	vimc_streamer_pipeline_terminate(stream);
-	return -EINVAL;
+	return ret;
 }
 
 /**
-- 
2.20.1


  parent reply	other threads:[~2019-10-24  9:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-24  9:35 [PATCH v4 0/2] upon streaming, check that the pipeline starts with a source entity Dafna Hirschfeld
2019-10-24  9:35 ` [PATCH v4 1/2] media: vimc: move the dev field of each entity to vimc_ent_dev Dafna Hirschfeld
2019-10-24  9:42   ` Hans Verkuil
2019-10-24 10:49     ` Dafna Hirschfeld
2019-10-24 23:28   ` Shuah Khan
2019-10-24  9:35 ` Dafna Hirschfeld [this message]
2019-10-24  9:44   ` [PATCH v4 2/2] media: vimc: upon streaming, check that the pipeline starts with a source entity Hans Verkuil
2019-10-24 11:48     ` Dafna Hirschfeld
2019-10-25  1:34   ` Shuah Khan
2019-11-01 20:31     ` Dafna Hirschfeld

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