On Sat Feb 21 13:56:18 2026 +0100, Abd-Alrhman Masalkhi wrote:
> vidtv_ts_null_write_into() and vidtv_ts_pcr_write_into() take their
> argument structs by value, causing MSAN to report uninit-value warnings.
> While only vidtv_ts_null_write_into() has triggered a report so far,
> both functions share the same issue.
>
> Fix by passing both structs by const pointer instead, avoiding the
> stack copy of the struct along with its MSAN shadow and origin metadata.
> The functions do not modify the structs, which is enforced by the const
> qualifier.
>
> Fixes: f90cf6079bf67 ("media: vidtv: add a bridge driver")
> Cc: [email protected]
> Reported-by: [email protected]
> Closes: https://syzkaller.appspot.com/bug?extid=96f901260a0b2d29cd1a
> Tested-by: [email protected]
> Suggested-by: Yihan Ding <[email protected]>
> Signed-off-by: Abd-Alrhman Masalkhi <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Patch committed.
Thanks,
Hans Verkuil
drivers/media/test-drivers/vidtv/vidtv_mux.c | 4 +--
drivers/media/test-drivers/vidtv/vidtv_ts.c | 48 ++++++++++++++--------------
drivers/media/test-drivers/vidtv/vidtv_ts.h | 4 +--
3 files changed, 28 insertions(+), 28 deletions(-)
---
diff --git a/drivers/media/test-drivers/vidtv/vidtv_mux.c
b/drivers/media/test-drivers/vidtv/vidtv_mux.c
index 403fbedb8663..f0134e38a1fb 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_mux.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_mux.c
@@ -233,7 +233,7 @@ static u32 vidtv_mux_push_pcr(struct vidtv_mux *m)
/* the 27Mhz clock will feed both parts of the PCR bitfield */
args.pcr = m->timing.clk;
- nbytes += vidtv_ts_pcr_write_into(args);
+ nbytes += vidtv_ts_pcr_write_into(&args);
m->mux_buf_offset += nbytes;
m->num_streamed_pcr++;
@@ -363,7 +363,7 @@ static u32 vidtv_mux_pad_with_nulls(struct vidtv_mux *m,
u32 npkts)
args.continuity_counter = &ctx->cc;
for (i = 0; i < npkts; ++i) {
- m->mux_buf_offset += vidtv_ts_null_write_into(args);
+ m->mux_buf_offset += vidtv_ts_null_write_into(&args);
args.dest_offset = m->mux_buf_offset;
}
diff --git a/drivers/media/test-drivers/vidtv/vidtv_ts.c
b/drivers/media/test-drivers/vidtv/vidtv_ts.c
index ca4bb9c40b78..cbe9aff9ffb5 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_ts.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_ts.c
@@ -48,7 +48,7 @@ void vidtv_ts_inc_cc(u8 *continuity_counter)
*continuity_counter = 0;
}
-u32 vidtv_ts_null_write_into(struct null_packet_write_args args)
+u32 vidtv_ts_null_write_into(const struct null_packet_write_args *args)
{
u32 nbytes = 0;
struct vidtv_mpeg_ts ts_header = {};
@@ -56,21 +56,21 @@ u32 vidtv_ts_null_write_into(struct null_packet_write_args
args)
ts_header.sync_byte = TS_SYNC_BYTE;
ts_header.bitfield = cpu_to_be16(TS_NULL_PACKET_PID);
ts_header.payload = 1;
- ts_header.continuity_counter = *args.continuity_counter;
+ ts_header.continuity_counter = *args->continuity_counter;
/* copy TS header */
- nbytes += vidtv_memcpy(args.dest_buf,
- args.dest_offset + nbytes,
- args.buf_sz,
+ nbytes += vidtv_memcpy(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->buf_sz,
&ts_header,
sizeof(ts_header));
- vidtv_ts_inc_cc(args.continuity_counter);
+ vidtv_ts_inc_cc(args->continuity_counter);
/* fill the rest with empty data */
- nbytes += vidtv_memset(args.dest_buf,
- args.dest_offset + nbytes,
- args.buf_sz,
+ nbytes += vidtv_memset(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->buf_sz,
TS_FILL_BYTE,
TS_PACKET_LEN - nbytes);
@@ -83,17 +83,17 @@ u32 vidtv_ts_null_write_into(struct null_packet_write_args
args)
return nbytes;
}
-u32 vidtv_ts_pcr_write_into(struct pcr_write_args args)
+u32 vidtv_ts_pcr_write_into(const struct pcr_write_args *args)
{
u32 nbytes = 0;
struct vidtv_mpeg_ts ts_header = {};
struct vidtv_mpeg_ts_adaption ts_adap = {};
ts_header.sync_byte = TS_SYNC_BYTE;
- ts_header.bitfield = cpu_to_be16(args.pid);
+ ts_header.bitfield = cpu_to_be16(args->pid);
ts_header.scrambling = 0;
/* cc is not incremented, but it is needed. see 13818-1 clause 2.4.3.3
*/
- ts_header.continuity_counter = *args.continuity_counter;
+ ts_header.continuity_counter = *args->continuity_counter;
ts_header.payload = 0;
ts_header.adaptation_field = 1;
@@ -102,27 +102,27 @@ u32 vidtv_ts_pcr_write_into(struct pcr_write_args args)
ts_adap.PCR = 1;
/* copy TS header */
- nbytes += vidtv_memcpy(args.dest_buf,
- args.dest_offset + nbytes,
- args.buf_sz,
+ nbytes += vidtv_memcpy(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->buf_sz,
&ts_header,
sizeof(ts_header));
/* write the adap after the TS header */
- nbytes += vidtv_memcpy(args.dest_buf,
- args.dest_offset + nbytes,
- args.buf_sz,
+ nbytes += vidtv_memcpy(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->buf_sz,
&ts_adap,
sizeof(ts_adap));
/* write the PCR optional */
- nbytes += vidtv_ts_write_pcr_bits(args.dest_buf,
- args.dest_offset + nbytes,
- args.pcr);
+ nbytes += vidtv_ts_write_pcr_bits(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->pcr);
- nbytes += vidtv_memset(args.dest_buf,
- args.dest_offset + nbytes,
- args.buf_sz,
+ nbytes += vidtv_memset(args->dest_buf,
+ args->dest_offset + nbytes,
+ args->buf_sz,
TS_FILL_BYTE,
TS_PACKET_LEN - nbytes);
diff --git a/drivers/media/test-drivers/vidtv/vidtv_ts.h
b/drivers/media/test-drivers/vidtv/vidtv_ts.h
index 09b4ffd02829..3606398e160d 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_ts.h
+++ b/drivers/media/test-drivers/vidtv/vidtv_ts.h
@@ -90,7 +90,7 @@ void vidtv_ts_inc_cc(u8 *continuity_counter);
*
* Return: The number of bytes written into the buffer.
*/
-u32 vidtv_ts_null_write_into(struct null_packet_write_args args);
+u32 vidtv_ts_null_write_into(const struct null_packet_write_args *args);
/**
* vidtv_ts_pcr_write_into - Write a PCR packet into a buffer.
@@ -101,6 +101,6 @@ u32 vidtv_ts_null_write_into(struct null_packet_write_args
args);
*
* Return: The number of bytes written into the buffer.
*/
-u32 vidtv_ts_pcr_write_into(struct pcr_write_args args);
+u32 vidtv_ts_pcr_write_into(const struct pcr_write_args *args);
#endif //VIDTV_TS_H
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