Merge branch 'kmemleak' of git://linux-arm.org/linux-2.6

* 'kmemleak' of git://linux-arm.org/linux-2.6:
  kmemleak: Improve the "Early log buffer exceeded" error message
  kmemleak: fix sparse warning for static declarations
  kmemleak: fix sparse warning over overshadowed flags
  kmemleak: move common painting code together
  kmemleak: add clear command support
  kmemleak: use bool for true/false questions
  kmemleak: Do no create the clean-up thread during kmemleak_disable()
  kmemleak: Scan all thread stacks
  kmemleak: Don't scan uninitialized memory when kmemcheck is enabled
  kmemleak: Ignore the aperture memory hole on x86_64
  kmemleak: Printing of the objects hex dump
  kmemleak: Do not report alloc_bootmem blocks as leaks
  kmemleak: Save the stack trace for early allocations
  kmemleak: Mark the early log buffer as __initdata
  kmemleak: Dump object information on request
  kmemleak: Allow rescheduling during an object scanning

Documentation/kmemleak.txt

@@ -27,6 +27,13 @@ To trigger an intermediate memory scan:
 
   # echo scan > /sys/kernel/debug/kmemleak
 
+To clear the list of all current possible memory leaks:
+
+  # echo clear > /sys/kernel/debug/kmemleak
+
+New leaks will then come up upon reading /sys/kernel/debug/kmemleak
+again.
+
 Note that the orphan objects are listed in the order they were allocated
 and one object at the beginning of the list may cause other subsequent
 objects to be reported as orphan.
@@ -42,6 +49,9 @@ Memory scanning parameters can be modified at run-time by writing to the
   scan=<secs>	- set the automatic memory scanning period in seconds
 		  (default 600, 0 to stop the automatic scanning)
   scan		- trigger a memory scan
+  clear		- clear list of current memory leak suspects, done by
+		  marking all current reported unreferenced objects grey
+  dump=<addr>	- dump information about the object found at <addr>
 
 Kmemleak can also be disabled at boot-time by passing "kmemleak=off" on
 the kernel command line.
@@ -86,6 +96,27 @@ avoid this, kmemleak can also store the number of values pointing to an
 address inside the block address range that need to be found so that the
 block is not considered a leak. One example is __vmalloc().
 
+Testing specific sections with kmemleak
+---------------------------------------
+
+Upon initial bootup your /sys/kernel/debug/kmemleak output page may be
+quite extensive. This can also be the case if you have very buggy code
+when doing development. To work around these situations you can use the
+'clear' command to clear all reported unreferenced objects from the
+/sys/kernel/debug/kmemleak output. By issuing a 'scan' after a 'clear'
+you can find new unreferenced objects; this should help with testing
+specific sections of code.
+
+To test a critical section on demand with a clean kmemleak do:
+
+  # echo clear > /sys/kernel/debug/kmemleak
+  ... test your kernel or modules ...
+  # echo scan > /sys/kernel/debug/kmemleak
+
+Then as usual to get your report with:
+
+  # cat /sys/kernel/debug/kmemleak
+
 Kmemleak API
 ------------
 

arch/x86/kernel/aperture_64.c

@@ -20,6 +20,7 @@
 #include <linux/bitops.h>
 #include <linux/ioport.h>
 #include <linux/suspend.h>
+#include <linux/kmemleak.h>
 #include <asm/e820.h>
 #include <asm/io.h>
 #include <asm/iommu.h>
@@ -94,6 +95,11 @@ static u32 __init allocate_aperture(void)
 	 * code for safe
 	 */
 	p = __alloc_bootmem_nopanic(aper_size, aper_size, 512ULL<<20);
+	/*
+	 * Kmemleak should not scan this block as it may not be mapped via the
+	 * kernel direct mapping.
+	 */
+	kmemleak_ignore(p);
 	if (!p || __pa(p)+aper_size > 0xffffffff) {
 		printk(KERN_ERR
 			"Cannot allocate aperture memory hole (%p,%uK)\n",

arch/x86/kernel/pci-dma.c

@@ -3,6 +3,7 @@
 #include <linux/dmar.h>
 #include <linux/bootmem.h>
 #include <linux/pci.h>
+#include <linux/kmemleak.h>
 
 #include <asm/proto.h>
 #include <asm/dma.h>
@@ -88,6 +89,11 @@ void __init dma32_reserve_bootmem(void)
 	size = roundup(dma32_bootmem_size, align);
 	dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align,
 				 512ULL<<20);
+	/*
+	 * Kmemleak should not scan this block as it may not be mapped via the
+	 * kernel direct mapping.
+	 */
+	kmemleak_ignore(dma32_bootmem_ptr);
 	if (dma32_bootmem_ptr)
 		dma32_bootmem_size = size;
 	else

arch/x86/mm/kmemcheck/kmemcheck.c

@@ -331,6 +331,20 @@ static void kmemcheck_read_strict(struct pt_regs *regs,
 	kmemcheck_shadow_set(shadow, size);
 }
 
+bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size)
+{
+	enum kmemcheck_shadow status;
+	void *shadow;
+
+	shadow = kmemcheck_shadow_lookup(addr);
+	if (!shadow)
+		return true;
+
+	status = kmemcheck_shadow_test(shadow, size);
+
+	return status == KMEMCHECK_SHADOW_INITIALIZED;
+}
+
 /* Access may cross page boundary */
 static void kmemcheck_read(struct pt_regs *regs,
 	unsigned long addr, unsigned int size)

include/linux/kmemcheck.h

@@ -34,6 +34,8 @@ void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n);
 int kmemcheck_show_addr(unsigned long address);
 int kmemcheck_hide_addr(unsigned long address);
 
+bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size);
+
 #else
 #define kmemcheck_enabled 0
 
@@ -99,6 +101,11 @@ static inline void kmemcheck_mark_initialized_pages(struct page *p,
 {
 }
 
+static inline bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size)
+{
+	return true;
+}
+
 #endif /* CONFIG_KMEMCHECK */
 
 /*

include/linux/kmemleak.h

@@ -23,18 +23,18 @@
 
 #ifdef CONFIG_DEBUG_KMEMLEAK
 
-extern void kmemleak_init(void);
+extern void kmemleak_init(void) __ref;
 extern void kmemleak_alloc(const void *ptr, size_t size, int min_count,
-			   gfp_t gfp);
-extern void kmemleak_free(const void *ptr);
-extern void kmemleak_free_part(const void *ptr, size_t size);
+			   gfp_t gfp) __ref;
+extern void kmemleak_free(const void *ptr) __ref;
+extern void kmemleak_free_part(const void *ptr, size_t size) __ref;
 extern void kmemleak_padding(const void *ptr, unsigned long offset,
-			     size_t size);
-extern void kmemleak_not_leak(const void *ptr);
-extern void kmemleak_ignore(const void *ptr);
+			     size_t size) __ref;
+extern void kmemleak_not_leak(const void *ptr) __ref;
+extern void kmemleak_ignore(const void *ptr) __ref;
 extern void kmemleak_scan_area(const void *ptr, unsigned long offset,
-			       size_t length, gfp_t gfp);
-extern void kmemleak_no_scan(const void *ptr);
+			       size_t length, gfp_t gfp) __ref;
+extern void kmemleak_no_scan(const void *ptr) __ref;
 
 static inline void kmemleak_alloc_recursive(const void *ptr, size_t size,
 					    int min_count, unsigned long flags,

mm/bootmem.c

@@ -521,7 +521,11 @@ find_block:
 		region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
 				start_off);
 		memset(region, 0, size);
-		kmemleak_alloc(region, size, 1, 0);
+		/*
+		 * The min_count is set to 0 so that bootmem allocated blocks
+		 * are never reported as leaks.
+		 */
+		kmemleak_alloc(region, size, 0, 0);
 		return region;
 	}