This is a note to let you know that I've just added the patch titled
media: v4l2-mem2mem: add lock to protect parameter num_rdy
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-v4l2-mem2mem-add-lock-to-protect-parameter-num.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a82f7d1ab939674c87a8224b0af46079ba97fabf
Author: Yunfei Dong <yunfei.dong@xxxxxxxxxxxx>
Date: Mon Apr 17 16:17:40 2023 +0800
media: v4l2-mem2mem: add lock to protect parameter num_rdy
[ 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 <pina.chen@xxxxxxxxxxxx>
Signed-off-by: Yunfei Dong <yunfei.dong@xxxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/media/v4l2-mem2mem.h b/include/media/v4l2-mem2mem.h
index 0b9c3a287061e..57b48c33f56cf 100644
--- a/include/media/v4l2-mem2mem.h
+++ b/include/media/v4l2-mem2mem.h
@@ -401,7 +401,14 @@ 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;
}
/**
@@ -413,7 +420,14 @@ 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;
}
/**
