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Commit 6c132d1b authored by David Woodhouse's avatar David Woodhouse Committed by Joerg Roedel
Browse files

dma-debug: print stacktrace of mapping path on unmap error 



Impact: saves stacktrace of a dma mapping and prints it if there is an  error

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent 187f9c3f

lib/dma-debug.c

+38 −14
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 


#include <linux/scatterlist.h>

#include <linux/dma-mapping.h>

#include <linux/stacktrace.h>

#include <linux/dma-debug.h>

#include <linux/spinlock.h>

#include <linux/debugfs.h>
@@ -39,6 +40,8 @@ enum { 
	dma_debug_coherent,

};



#define DMA_DEBUG_STACKTRACE_ENTRIES 5



struct dma_debug_entry {

	struct list_head list;

	struct device    *dev;
@@ -49,6 +52,10 @@ struct dma_debug_entry { 
	int              direction;

	int		 sg_call_ents;

	int		 sg_mapped_ents;

#ifdef CONFIG_STACKTRACE

	struct		 stack_trace stacktrace;

	unsigned long	 st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];

#endif

};



struct hash_bucket {
@@ -108,12 +115,23 @@ static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE", 
 *                    system log than the user configured. This variable is

 *                    writeable via debugfs.

 */

#define err_printk(dev, format, arg...) do {			\

static inline void dump_entry_trace(struct dma_debug_entry *entry)

{

#ifdef CONFIG_STACKTRACE

	if (entry) {

		printk(KERN_WARNING "Mapped at:\n");

		print_stack_trace(&entry->stacktrace, 0);

	}

#endif

}



#define err_printk(dev, entry, format, arg...) do {		\

		error_count += 1;				\

		if (show_all_errors || show_num_errors > 0) {	\

			WARN(1, "%s %s: " format,		\

			     dev_driver_string(dev),		\

			     dev_name(dev) , ## arg);		\

			dump_entry_trace(entry);		\

		}						\

		if (!show_all_errors && show_num_errors > 0)	\

			show_num_errors -= 1;			\
@@ -260,6 +278,12 @@ static struct dma_debug_entry *dma_entry_alloc(void) 
	list_del(&entry->list);

	memset(entry, 0, sizeof(*entry));



#ifdef CONFIG_STACKTRACE

	entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;

	entry->stacktrace.entries = entry->st_entries;

	entry->stacktrace.skip = 2;

	save_stack_trace(&entry->stacktrace);

#endif

	num_free_entries -= 1;

	if (num_free_entries < min_free_entries)

		min_free_entries = num_free_entries;
@@ -457,7 +481,7 @@ static void check_unmap(struct dma_debug_entry *ref) 
	entry = hash_bucket_find(bucket, ref);



	if (!entry) {

		err_printk(ref->dev, "DMA-API: device driver tries "

		err_printk(ref->dev, NULL, "DMA-API: device driver tries "

			   "to free DMA memory it has not allocated "

			   "[device address=0x%016llx] [size=%llu bytes]\n",

			   ref->dev_addr, ref->size);
@@ -465,7 +489,7 @@ static void check_unmap(struct dma_debug_entry *ref) 
	}



	if (ref->size != entry->size) {

		err_printk(ref->dev, "DMA-API: device driver frees "

		err_printk(ref->dev, entry, "DMA-API: device driver frees "

			   "DMA memory with different size "

			   "[device address=0x%016llx] [map size=%llu bytes] "

			   "[unmap size=%llu bytes]\n",
@@ -473,7 +497,7 @@ static void check_unmap(struct dma_debug_entry *ref) 
	}



	if (ref->type != entry->type) {

		err_printk(ref->dev, "DMA-API: device driver frees "

		err_printk(ref->dev, entry, "DMA-API: device driver frees "

			   "DMA memory with wrong function "

			   "[device address=0x%016llx] [size=%llu bytes] "

			   "[mapped as %s] [unmapped as %s]\n",
@@ -481,7 +505,7 @@ static void check_unmap(struct dma_debug_entry *ref) 
			   type2name[entry->type], type2name[ref->type]);

	} else if ((entry->type == dma_debug_coherent) &&

		   (ref->paddr != entry->paddr)) {

		err_printk(ref->dev, "DMA-API: device driver frees "

		err_printk(ref->dev, entry, "DMA-API: device driver frees "

			   "DMA memory with different CPU address "

			   "[device address=0x%016llx] [size=%llu bytes] "

			   "[cpu alloc address=%p] [cpu free address=%p]",
@@ -491,7 +515,7 @@ static void check_unmap(struct dma_debug_entry *ref) 


	if (ref->sg_call_ents && ref->type == dma_debug_sg &&

	    ref->sg_call_ents != entry->sg_call_ents) {

		err_printk(ref->dev, "DMA-API: device driver frees "

		err_printk(ref->dev, entry, "DMA-API: device driver frees "

			   "DMA sg list with different entry count "

			   "[map count=%d] [unmap count=%d]\n",

			   entry->sg_call_ents, ref->sg_call_ents);
@@ -502,7 +526,7 @@ static void check_unmap(struct dma_debug_entry *ref) 
	 * DMA API don't handle this properly, so check for it here

	 */

	if (ref->direction != entry->direction) {

		err_printk(ref->dev, "DMA-API: device driver frees "

		err_printk(ref->dev, entry, "DMA-API: device driver frees "

			   "DMA memory with different direction "

			   "[device address=0x%016llx] [size=%llu bytes] "

			   "[mapped with %s] [unmapped with %s]\n",
@@ -521,8 +545,8 @@ out: 
static void check_for_stack(struct device *dev, void *addr)

{

	if (object_is_on_stack(addr))

		err_printk(dev, "DMA-API: device driver maps memory from stack"

				" [addr=%p]\n", addr);

		err_printk(dev, NULL, "DMA-API: device driver maps memory from"

				"stack [addr=%p]\n", addr);

}



static void check_sync(struct device *dev, dma_addr_t addr,
@@ -543,7 +567,7 @@ static void check_sync(struct device *dev, dma_addr_t addr, 
	entry = hash_bucket_find(bucket, &ref);



	if (!entry) {

		err_printk(dev, "DMA-API: device driver tries "

		err_printk(dev, NULL, "DMA-API: device driver tries "

				"to sync DMA memory it has not allocated "

				"[device address=0x%016llx] [size=%llu bytes]\n",

				addr, size);
@@ -551,7 +575,7 @@ static void check_sync(struct device *dev, dma_addr_t addr, 
	}



	if ((offset + size) > entry->size) {

		err_printk(dev, "DMA-API: device driver syncs"

		err_printk(dev, entry, "DMA-API: device driver syncs"

				" DMA memory outside allocated range "

				"[device address=0x%016llx] "

				"[allocation size=%llu bytes] [sync offset=%llu] "
@@ -560,7 +584,7 @@ static void check_sync(struct device *dev, dma_addr_t addr, 
	}



	if (direction != entry->direction) {

		err_printk(dev, "DMA-API: device driver syncs "

		err_printk(dev, entry, "DMA-API: device driver syncs "

				"DMA memory with different direction "

				"[device address=0x%016llx] [size=%llu bytes] "

				"[mapped with %s] [synced with %s]\n",
@@ -574,7 +598,7 @@ static void check_sync(struct device *dev, dma_addr_t addr, 


	if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&

		      !(direction == DMA_TO_DEVICE))

		err_printk(dev, "DMA-API: device driver syncs "

		err_printk(dev, entry, "DMA-API: device driver syncs "

				"device read-only DMA memory for cpu "

				"[device address=0x%016llx] [size=%llu bytes] "

				"[mapped with %s] [synced with %s]\n",
@@ -584,7 +608,7 @@ static void check_sync(struct device *dev, dma_addr_t addr, 


	if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&

		       !(direction == DMA_FROM_DEVICE))

		err_printk(dev, "DMA-API: device driver syncs "

		err_printk(dev, entry, "DMA-API: device driver syncs "

				"device write-only DMA memory to device "

				"[device address=0x%016llx] [size=%llu bytes] "

				"[mapped with %s] [synced with %s]\n",