From e01ea1c4191ee08440b5f86db98dff695e9cedf9 Mon Sep 17 00:00:00 2001 From: Yunfei Dong Date: Mon, 17 Apr 2023 16:17:40 +0800 Subject: [PATCH] media: v4l2-mem2mem: add lock to protect parameter num_rdy MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit 56b5c3e67b0f9af3f45cf393be048ee8d8a92694 ] Getting below error when using KCSAN to check the driver. Adding lock to protect parameter num_rdy when getting the value with function: v4l2_m2m_num_src_bufs_ready/v4l2_m2m_num_dst_bufs_ready. kworker/u16:3: [name:report&]BUG: KCSAN: data-race in v4l2_m2m_buf_queue kworker/u16:3: [name:report&] kworker/u16:3: [name:report&]read-write to 0xffffff8105f35b94 of 1 bytes by task 20865 on cpu 7: kworker/u16:3:  v4l2_m2m_buf_queue+0xd8/0x10c Signed-off-by: Pina Chen Signed-off-by: Yunfei Dong Signed-off-by: Hans Verkuil Signed-off-by: Sasha Levin --- include/media/v4l2-mem2mem.h | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/include/media/v4l2-mem2mem.h b/include/media/v4l2-mem2mem.h index bb9de6a899e07..d6c8eb2b52019 100644 --- a/include/media/v4l2-mem2mem.h +++ b/include/media/v4l2-mem2mem.h @@ -593,7 +593,14 @@ void v4l2_m2m_buf_queue(struct v4l2_m2m_ctx *m2m_ctx, static inline unsigned int v4l2_m2m_num_src_bufs_ready(struct v4l2_m2m_ctx *m2m_ctx) { - return m2m_ctx->out_q_ctx.num_rdy; + unsigned int num_buf_rdy; + unsigned long flags; + + spin_lock_irqsave(&m2m_ctx->out_q_ctx.rdy_spinlock, flags); + num_buf_rdy = m2m_ctx->out_q_ctx.num_rdy; + spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock, flags); + + return num_buf_rdy; } /** @@ -605,7 +612,14 @@ unsigned int v4l2_m2m_num_src_bufs_ready(struct v4l2_m2m_ctx *m2m_ctx) static inline unsigned int v4l2_m2m_num_dst_bufs_ready(struct v4l2_m2m_ctx *m2m_ctx) { - return m2m_ctx->cap_q_ctx.num_rdy; + unsigned int num_buf_rdy; + unsigned long flags; + + spin_lock_irqsave(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags); + num_buf_rdy = m2m_ctx->cap_q_ctx.num_rdy; + spin_unlock_irqrestore(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags); + + return num_buf_rdy; } /**