Thread (2 messages) flat view 2 messages, 2 authors, 2025-11-27
STALE290d

[PATCH v3] dma-buf: add some tracepoints to debug.

From: Xiang Gao <hidden>
Date: 2025-11-27 00:44:01
Also in: dri-devel, linux-media, lkml
Subsystem: dma buffer sharing framework, the rest, tracing · Maintainers: Sumit Semwal, Christian König, Linus Torvalds, Steven Rostedt, Masami Hiramatsu 

From: gaoxiang17 <redacted>

I want to track the status of dmabuf in real time in the production environment.
But now we can only check it by traversing the fd in the process or dmabuf_list.

For example:
   binder:2962_2-2962    [005] ...1.   208.453940: dma_buf_export: exp_name=qcom,system name=(null) size=28672 ino=2580 f_refcnt=2
   binder:2962_2-2962    [005] ...1.   208.453943: dma_buf_fd: exp_name=qcom,system name=(null) size=28672 ino=2580 fd=9 f_refcnt=2
   binder:2962_2-2962    [005] ...1.   208.453977: dma_buf_mmap_internal: exp_name=qcom,system name=qcom,system size=28672 ino=2580 f_refcnt=4
     kworker/5:2-194     [005] ...1.   208.460580: dma_buf_put: exp_name=qcom,system name=ab pid [8176] size=28672 ino=2580 f_refcnt=3
    RenderThread-11305   [007] ...1.   208.599094: dma_buf_get: exp_name=qcom,system name=ab pid [8176] size=217088 ino=2579 fd=1114 f_refcnt=7
    RenderThread-11305   [007] ...1.   208.599098: dma_buf_attach: dev_name=kgsl-3d0 exp_name=qcom,system name=ab pid [8176] size=217088 ino=2579 f_refcnt=7
           <...>-14      [001] ...1.   208.726359: dma_buf_detach: dev_name=kgsl-3d0 exp_name=qcom,system name=ab pid [3317] size=217088 ino=2581 f_refcnt=3

Signed-off-by: Xiang Gao <redacted>
---
 drivers/dma-buf/dma-buf.c      |  57 ++++++++++-
 include/trace/events/dma_buf.h | 166 +++++++++++++++++++++++++++++++++
 2 files changed, 222 insertions(+), 1 deletion(-)
 create mode 100644 include/trace/events/dma_buf.h

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 2bcf9ceca997..7cef816ddcac 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -35,6 +35,18 @@
 
 #include "dma-buf-sysfs-stats.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/dma_buf.h>
+
+EXPORT_TRACEPOINT_SYMBOL(dma_buf_export);
+EXPORT_TRACEPOINT_SYMBOL(dma_buf_mmap_internal);
+EXPORT_TRACEPOINT_SYMBOL(dma_buf_mmap);
+EXPORT_TRACEPOINT_SYMBOL(dma_buf_put);
+EXPORT_TRACEPOINT_SYMBOL(dma_buf_attach);
+EXPORT_TRACEPOINT_SYMBOL(dma_buf_detach);
+EXPORT_TRACEPOINT_SYMBOL(dma_buf_fd);
+EXPORT_TRACEPOINT_SYMBOL(dma_buf_get);
+
 static inline int is_dma_buf_file(struct file *);
 
 static DEFINE_MUTEX(dmabuf_list_mutex);
@@ -220,6 +232,11 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
 	    dmabuf->size >> PAGE_SHIFT)
 		return -EINVAL;
 
+	if (trace_dma_buf_mmap_internal_enabled()) {
+		guard(spinlock)(&dmabuf->name_lock);
+		trace_dma_buf_mmap_internal(dmabuf);
+	}
+
 	return dmabuf->ops->mmap(dmabuf, vma);
 }
 
@@ -745,6 +762,11 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 
 	__dma_buf_list_add(dmabuf);
 
+	if (trace_dma_buf_export_enabled()) {
+		guard(spinlock)(&dmabuf->name_lock);
+		trace_dma_buf_export(dmabuf);
+	}
+
 	return dmabuf;
 
 err_dmabuf:
@@ -779,6 +801,11 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags)
 
 	fd_install(fd, dmabuf->file);
 
+	if (trace_dma_buf_fd_enabled()) {
+		guard(spinlock)(&dmabuf->name_lock);
+		trace_dma_buf_fd(dmabuf, fd);
+	}
+
 	return fd;
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");
@@ -794,6 +821,7 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF");
 struct dma_buf *dma_buf_get(int fd)
 {
 	struct file *file;
+	struct dma_buf *dmabuf;
 
 	file = fget(fd);
 
@@ -805,7 +833,14 @@ struct dma_buf *dma_buf_get(int fd)
 		return ERR_PTR(-EINVAL);
 	}
 
-	return file->private_data;
+	dmabuf = file->private_data;
+
+	if (trace_dma_buf_get_enabled()) {
+		guard(spinlock)(&dmabuf->name_lock);
+		trace_dma_buf_get(dmabuf, fd);
+	}
+
+	return dmabuf;
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_get, "DMA_BUF");
 
@@ -825,6 +860,11 @@ void dma_buf_put(struct dma_buf *dmabuf)
 		return;
 
 	fput(dmabuf->file);
+
+	if (trace_dma_buf_put_enabled()) {
+		guard(spinlock)(&dmabuf->name_lock);
+		trace_dma_buf_put(dmabuf);
+	}
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_put, "DMA_BUF");
 
@@ -998,6 +1038,11 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_dynamic_attach, "DMA_BUF");
 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
 					  struct device *dev)
 {
+	if (trace_dma_buf_attach_enabled()) {
+		guard(spinlock)(&dmabuf->name_lock);
+		trace_dma_buf_attach(dmabuf, dev);
+	}
+
 	return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL);
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_attach, "DMA_BUF");
@@ -1023,6 +1068,11 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
 	if (dmabuf->ops->detach)
 		dmabuf->ops->detach(dmabuf, attach);
 
+	if (trace_dma_buf_detach_enabled()) {
+		guard(spinlock)(&dmabuf->name_lock);
+		trace_dma_buf_detach(dmabuf, attach->dev);
+	}
+
 	kfree(attach);
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_detach, "DMA_BUF");
@@ -1488,6 +1538,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
 	vma_set_file(vma, dmabuf->file);
 	vma->vm_pgoff = pgoff;
 
+	if (trace_dma_buf_mmap_enabled()) {
+		guard(spinlock)(&dmabuf->name_lock);
+		trace_dma_buf_mmap(dmabuf);
+	}
+
 	return dmabuf->ops->mmap(dmabuf, vma);
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, "DMA_BUF");
diff --git a/include/trace/events/dma_buf.h b/include/trace/events/dma_buf.h
new file mode 100644
index 000000000000..fe9da89bacd0
--- /dev/null
+++ b/include/trace/events/dma_buf.h
@@ -0,0 +1,166 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM dma_buf
+
+#if !defined(_TRACE_DMA_BUF_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_DMA_BUF_H
+
+#include <linux/dma-buf.h>
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(dma_buf,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf),
+
+	TP_STRUCT__entry(
+		__string(exp_name, dmabuf->exp_name)
+		__string(name, dmabuf->name)
+		__field(size_t, size)
+		__field(ino_t, ino)
+		__field(long, f_refcnt)
+	),
+
+	TP_fast_assign(
+		__assign_str(exp_name);
+		__assign_str(name);
+		__entry->size = dmabuf->size;
+		__entry->ino = dmabuf->file->f_inode->i_ino;
+		__entry->f_refcnt = file_count(dmabuf->file);
+	),
+
+	TP_printk("exp_name=%s name=%s size=%zu ino=%lu f_refcnt=%ld",
+		  __get_str(exp_name),
+		  __get_str(name),
+		  __entry->size,
+		  __entry->ino,
+		  __entry->f_refcnt)
+);
+
+DECLARE_EVENT_CLASS(dma_buf_attach_dev,
+
+	TP_PROTO(struct dma_buf *dmabuf, struct device *dev),
+
+	TP_ARGS(dmabuf, dev),
+
+	TP_STRUCT__entry(
+		__string(dname, dev_name(dev))
+		__string(exp_name, dmabuf->exp_name)
+		__string(name, dmabuf->name)
+		__field(size_t, size)
+		__field(ino_t, ino)
+		__field(long, f_refcnt)
+	),
+
+	TP_fast_assign(
+		__assign_str(dname);
+		__assign_str(exp_name);
+		__assign_str(name);
+		__entry->size = dmabuf->size;
+		__entry->ino = dmabuf->file->f_inode->i_ino;
+		__entry->f_refcnt = file_count(dmabuf->file);
+	),
+
+	TP_printk("dev_name=%s exp_name=%s name=%s size=%zu ino=%lu f_refcnt=%ld",
+		  __get_str(dname),
+		  __get_str(exp_name),
+		  __get_str(name),
+		  __entry->size,
+		  __entry->ino,
+		  __entry->f_refcnt)
+);
+
+DECLARE_EVENT_CLASS(dma_buf_fd,
+
+	TP_PROTO(struct dma_buf *dmabuf, int fd),
+
+	TP_ARGS(dmabuf, fd),
+
+	TP_STRUCT__entry(
+		__string(exp_name, dmabuf->exp_name)
+		__string(name, dmabuf->name)
+		__field(size_t, size)
+		__field(ino_t, ino)
+		__field(int, fd)
+		__field(long, f_refcnt)
+	),
+
+	TP_fast_assign(
+		__assign_str(exp_name);
+		__assign_str(name);
+		__entry->size = dmabuf->size;
+		__entry->ino = dmabuf->file->f_inode->i_ino;
+		__entry->fd = fd;
+		__entry->f_refcnt = file_count(dmabuf->file);
+	),
+
+	TP_printk("exp_name=%s name=%s size=%zu ino=%lu fd=%d f_refcnt=%ld",
+		  __get_str(exp_name),
+		  __get_str(name),
+		  __entry->size,
+		  __entry->ino,
+		  __entry->fd,
+		  __entry->f_refcnt)
+);
+
+DEFINE_EVENT(dma_buf, dma_buf_export,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf)
+);
+
+DEFINE_EVENT(dma_buf, dma_buf_mmap_internal,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf)
+);
+
+DEFINE_EVENT(dma_buf, dma_buf_mmap,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf)
+);
+
+DEFINE_EVENT(dma_buf, dma_buf_put,
+
+	TP_PROTO(struct dma_buf *dmabuf),
+
+	TP_ARGS(dmabuf)
+);
+
+DEFINE_EVENT(dma_buf_attach_dev, dma_buf_attach,
+
+	TP_PROTO(struct dma_buf *dmabuf, struct device *dev),
+
+	TP_ARGS(dmabuf, dev)
+);
+
+DEFINE_EVENT(dma_buf_attach_dev, dma_buf_detach,
+
+	TP_PROTO(struct dma_buf *dmabuf, struct device *dev),
+
+	TP_ARGS(dmabuf, dev)
+);
+
+DEFINE_EVENT(dma_buf_fd, dma_buf_fd,
+
+	TP_PROTO(struct dma_buf *dmabuf, int fd),
+
+	TP_ARGS(dmabuf, fd)
+);
+
+DEFINE_EVENT(dma_buf_fd, dma_buf_get,
+
+	TP_PROTO(struct dma_buf *dmabuf, int fd),
+
+	TP_ARGS(dmabuf, fd)
+);
+
+#endif /* _TRACE_DMA_BUF_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.34.1
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