Merge "dma-buf: Add reference count leak tracing" (d88574df) · Commits · e / devices / android_kernel_oneplus_sm8150

drivers/dma-buf/Kconfig

+11 −0

Original line number	Diff line number	Diff line
		@@ -30,4 +30,15 @@ config SW_SYNC
		WARNING: improper use of this can result in deadlocking kernel
		drivers from userspace. Intended for test and debug only.

		config DEBUG_DMA_BUF_REF
		bool "DEBUG Reference Count"
		depends on STACKDEPOT
		depends on DMA_SHARED_BUFFER
		default n
		---help---
		Save stack traces for every call to dma_buf_get and dma_buf_put, to
		help debug memory leaks. Potential leaks may be found by manually
		matching the get/put call stacks. This feature consumes extra memory
		in order to save the stack traces using STACKDEPOT.

		endmenu

drivers/dma-buf/Makefile

+1 −0

Original line number	Diff line number	Diff line
		obj-y := dma-buf.o dma-fence.o dma-fence-array.o reservation.o seqno-fence.o
		obj-$(CONFIG_SYNC_FILE) += sync_file.o
		obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
		obj-$(CONFIG_DEBUG_DMA_BUF_REF) += dma-buf-ref.o

drivers/dma-buf/dma-buf-ref.c

0 → 100644

+123 −0

Original line number	Diff line number	Diff line
		/* Copyright (c) 2018, The Linux Foundation. All rights reserved.
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 and
		* only version 2 as published by the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		*/

		#include <linux/dma-buf.h>
		#include <linux/slab.h>
		#include <linux/stackdepot.h>
		#include <linux/stacktrace.h>
		#include <linux/seq_file.h>

		#define DMA_BUF_STACK_DEPTH (16)

		struct dma_buf_ref {
		struct list_head list;
		depot_stack_handle_t handle;
		int count;
		};

		void dma_buf_ref_init(struct dma_buf *dmabuf)
		{
		INIT_LIST_HEAD(&dmabuf->refs);
		}

		void dma_buf_ref_destroy(struct dma_buf *dmabuf)
		{
		struct dma_buf_ref r, n;

		mutex_lock(&dmabuf->lock);
		list_for_each_entry_safe(r, n, &dmabuf->refs, list) {
		list_del(&r->list);
		kfree(r);
		}
		mutex_unlock(&dmabuf->lock);
		}

		static void dma_buf_ref_insert_handle(struct dma_buf *dmabuf,
		depot_stack_handle_t handle,
		int count)
		{
		struct dma_buf_ref *r;

		mutex_lock(&dmabuf->lock);
		list_for_each_entry(r, &dmabuf->refs, list) {
		if (r->handle == handle) {
		r->count += count;
		goto out;
		}
		}

		r = kzalloc(sizeof(*r), GFP_KERNEL);
		if (!r)
		goto out;

		INIT_LIST_HEAD(&r->list);
		r->handle = handle;
		r->count = count;
		list_add(&r->list, &dmabuf->refs);

		out:
		mutex_unlock(&dmabuf->lock);
		}

		void dma_buf_ref_mod(struct dma_buf *dmabuf, int nr)
		{
		unsigned long entries[DMA_BUF_STACK_DEPTH];
		struct stack_trace trace = {
		.nr_entries = 0,
		.entries = entries,
		.max_entries = DMA_BUF_STACK_DEPTH,
		.skip = 1
		};
		depot_stack_handle_t handle;

		save_stack_trace(&trace);
		if (trace.nr_entries != 0 &&
		trace.entries[trace.nr_entries-1] == ULONG_MAX)
		trace.nr_entries--;

		handle = depot_save_stack(&trace, GFP_KERNEL);
		if (!handle)
		return;

		dma_buf_ref_insert_handle(dmabuf, handle, nr);
		}

		/**
		* Called with dmabuf->lock held
		*/
		int dma_buf_ref_show(struct seq_file s, struct dma_buf dmabuf)
		{
		char *buf;
		struct dma_buf_ref *ref;
		int count = 0;
		struct stack_trace trace;

		buf = (void *)__get_free_page(GFP_KERNEL);
		if (!buf)
		return -ENOMEM;

		list_for_each_entry(ref, &dmabuf->refs, list) {
		count += ref->count;

		seq_printf(s, "References: %d\n", ref->count);
		depot_fetch_stack(ref->handle, &trace);
		snprint_stack_trace(buf, PAGE_SIZE, &trace, 0);
		seq_puts(s, buf);
		seq_putc(s, '\n');
		}

		seq_printf(s, "Total references: %d\n\n\n", count);
		free_page((unsigned long)buf);

		return 0;
		}

drivers/dma-buf/dma-buf.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -93,6 +93,8 @@ static int dma_buf_release(struct inode inode, struct file file)
		list_del(&dmabuf->list_node);
		mutex_unlock(&db_list.lock);

		dma_buf_ref_destroy(dmabuf);

		if (dmabuf->resv == (struct reservation_object *)&dmabuf[1])
		reservation_object_fini(dmabuf->resv);

		@@ -495,6 +497,9 @@ struct dma_buf dma_buf_export(const struct dma_buf_export_info exp_info)
		mutex_init(&dmabuf->lock);
		INIT_LIST_HEAD(&dmabuf->attachments);

		dma_buf_ref_init(dmabuf);
		dma_buf_ref_mod(dmabuf, 1);

		mutex_lock(&db_list.lock);
		list_add(&dmabuf->list_node, &db_list.head);
		mutex_unlock(&db_list.lock);
		@@ -556,6 +561,7 @@ struct dma_buf *dma_buf_get(int fd)
		fput(file);
		return ERR_PTR(-EINVAL);
		}
		dma_buf_ref_mod(file->private_data, 1);

		return file->private_data;
		}
		@@ -576,6 +582,7 @@ void dma_buf_put(struct dma_buf *dmabuf)
		if (WARN_ON(!dmabuf \|\| !dmabuf->file))
		return;

		dma_buf_ref_mod(dmabuf, -1);
		fput(dmabuf->file);
		}
		EXPORT_SYMBOL_GPL(dma_buf_put);
		@@ -1266,6 +1273,8 @@ static int dma_buf_debug_show(struct seq_file s, void unused)
		seq_printf(s, "Total %d devices attached\n\n",
		attach_count);

		dma_buf_ref_show(s, buf_obj);

		count++;
		size += buf_obj->size;
		mutex_unlock(&buf_obj->lock);

include/linux/dma-buf-ref.h

0 → 100644

+36 −0

Original line number	Diff line number	Diff line
		/* Copyright (c) 2018, The Linux Foundation. All rights reserved.
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 and
		* only version 2 as published by the Free Software Foundation.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*/

		#ifndef _DMA_BUF_REF_H
		#define _DMA_BUF_REF_H

		struct dma_buf;
		struct seq_file;

		#ifdef CONFIG_DEBUG_DMA_BUF_REF
		void dma_buf_ref_init(struct dma_buf *b);
		void dma_buf_ref_destroy(struct dma_buf *b);
		void dma_buf_ref_mod(struct dma_buf *b, int nr);
		int dma_buf_ref_show(struct seq_file s, struct dma_buf dmabuf);

		#else
		static inline void dma_buf_ref_init(struct dma_buf *b) {}
		static inline void dma_buf_ref_destroy(struct dma_buf *b) {}
		static inline void dma_buf_ref_mod(struct dma_buf *b, int nr) {}
		static inline int dma_buf_ref_show(struct seq_file s, struct dma_buf dmabuf)
		{
		return -ENOMEM;
		}
		#endif


		#endif /* _DMA_BUF_REF_H */