Messages in this thread Patch in this message | | | Subject | Re: [PATCH 0/16] DMA-API debugging facility v3 | From | David Woodhouse <> | Date | Wed, 25 Feb 2009 16:33:19 +0900 |
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Where we complain about a discrepancy between unmap/sync and the original mapping, it can sometimes be useful to see the backtrace of the code which _mapped_ the region originally.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> --- Untested. Builds though. Thanks Johannes for pointing me at an example.
diff --git a/lib/dma-debug.c b/lib/dma-debug.c index 9c1a498..79542db 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -26,6 +26,7 @@ #include <linux/types.h> #include <linux/sched.h> #include <linux/list.h> +#include <linux/stacktrace.h> #include <linux/slab.h> #define HASH_SIZE 256 @@ -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; @@ -47,6 +50,10 @@ struct dma_debug_entry { u64 dev_addr; u64 size; int direction; +#ifdef CONFIG_STACKTRACE + struct stack_trace stacktrace; + unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES]; +#endif }; struct hash_bucket { @@ -106,13 +113,24 @@ 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; \ } while (0); @@ -258,6 +276,12 @@ 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 = 1; + save_stack_trace(&entry->stacktrace); +#endif num_free_entries -= 1; if (num_free_entries < min_free_entries) min_free_entries = num_free_entries; @@ -455,7 +479,7 @@ 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); @@ -463,7 +487,7 @@ 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", @@ -471,7 +495,7 @@ 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", @@ -479,7 +503,7 @@ 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]", @@ -492,7 +516,7 @@ 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", @@ -511,8 +535,8 @@ 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, @@ -533,7 +557,7 @@ 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); @@ -541,7 +565,7 @@ 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] " @@ -550,7 +574,7 @@ 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", @@ -564,7 +588,7 @@ 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", @@ -574,7 +598,7 @@ 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", -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation
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