[PATCH] media: vidtv: fix uninitialized args.buf_sz passed by value

[Abd-Alrhman Masalkhi]

vidtv_ts_null_write_into() takes null_packet_write_args by value,
causing MSAN to report an uninit-value warning on buf_sz inside
the function.

Fix by passing the struct by pointer instead, avoiding the stack copy
entirely.

Reported-by: syzbot+96f901260a0b2d29cd1a@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=96f901260a0b2d29cd1a
Fixes: cd7a5651db26 ("alpha: add missing address argument in call to page_table_check_pte_clear()")
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@xxxxxxxxx>
---
 drivers/media/test-drivers/vidtv/vidtv_mux.c |  2 +-
 drivers/media/test-drivers/vidtv/vidtv_ts.c  | 18 +++++++++---------
 drivers/media/test-drivers/vidtv/vidtv_ts.h  |  2 +-
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/media/test-drivers/vidtv/vidtv_mux.c b/drivers/media/test-drivers/vidtv/vidtv_mux.c
index f99878eff7ac..67a580396112 100644
--- a/drivers/media/test-drivers/vidtv/vidtv_mux.c
+++ b/drivers/media/test-drivers/vidtv/vidtv_mux.c
@@ -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..7e6e92503fb8 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(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);
 
diff --git a/drivers/media/test-drivers/vidtv/vidtv_ts.h b/drivers/media/test-drivers/vidtv/vidtv_ts.h
index 09b4ffd02829..28da15dcc697 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(struct null_packet_write_args *args);
 
 /**
  * vidtv_ts_pcr_write_into - Write a PCR  packet into a buffer.
-- 
2.43.0