MM: virtual address debug

Add some (configurable) expensive sanity checking to catch wrong address translations on x86. - create linux/mmdebug.h file to be able include this file in asm headers to not get unsolvable loops in header files - __phys_addr on x86_32 became a function in ioremap.c since PAGE_OFFSET, is_vmalloc_addr and VMALLOC_* non-constasts are undefined if declared in page_32.h - add __phys_addr_const for initializing doublefault_tss.__cr3 Tested on 386, 386pae, x86_64 and x86_64 numa=fake=2. Contains Andi's enable numa virtual address debug patch. Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>

MM: virtual address debug
Add some (configurable) expensive sanity checking to catch wrong address translations on x86. - create linux/mmdebug.h file to be able include this file in asm headers to not get unsolvable loops in header files - __phys_addr on x86_32 became a function in ioremap.c since PAGE_OFFSET, is_vmalloc_addr and VMALLOC_* non-constasts are undefined if declared in page_32.h - add __phys_addr_const for initializing doublefault_tss.__cr3 Tested on 386, 386pae, x86_64 and x86_64 numa=fake=2. Contains Andi's enable numa virtual address debug patch. Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Jiri Slaby · Ingo Molnar
1 parent 952f4a0a9b
Showing 8 changed files with 61 additions and 16 deletions Side-by-side Diff
arch/x86/kernel/doublefault_32.c
arch/x86/mm/ioremap.c
include/asm-x86/mmzone_64.h
include/asm-x86/page_32.h
include/linux/mm.h
include/linux/mmdebug.h
lib/Kconfig.debug
mm/vmalloc.c
@@ -66,7 +66,7 @@
 		.ds		= __USER_DS,
 		.fs		= __KERNEL_PERCPU,
  
-		.__cr3		= __pa(swapper_pg_dir)
+		.__cr3		= __phys_addr_const((unsigned long)swapper_pg_dir)
 	}
 };
@@ -23,18 +23,26 @@
  
 #ifdef CONFIG_X86_64
  
-unsigned long __phys_addr(unsigned long x)
+static inline int phys_addr_valid(unsigned long addr)
 {
-	if (x >= __START_KERNEL_map)
-		return x - __START_KERNEL_map + phys_base;
-	return x - PAGE_OFFSET;
+	return addr < (1UL << boot_cpu_data.x86_phys_bits);
 }
-EXPORT_SYMBOL(__phys_addr);
  
-static inline int phys_addr_valid(unsigned long addr)
+unsigned long __phys_addr(unsigned long x)
 {
-	return addr < (1UL << boot_cpu_data.x86_phys_bits);
+	if (x >= __START_KERNEL_map) {
+		x -= __START_KERNEL_map;
+		VIRTUAL_BUG_ON(x >= KERNEL_IMAGE_SIZE);
+		x += phys_base;
+	} else {
+		VIRTUAL_BUG_ON(x < PAGE_OFFSET);
+		x -= PAGE_OFFSET;
+		VIRTUAL_BUG_ON(system_state == SYSTEM_BOOTING ? x > MAXMEM :
+					!phys_addr_valid(x));
+	}
+	return x;
 }
+EXPORT_SYMBOL(__phys_addr);
  
 #else
  
@@ -42,6 +50,15 @@
 {
 	return 1;
 }
+
+unsigned long __phys_addr(unsigned long x)
+{
+	/* VMALLOC_* aren't constants; not available at the boot time */
+	VIRTUAL_BUG_ON(x < PAGE_OFFSET || (system_state != SYSTEM_BOOTING &&
+					is_vmalloc_addr((void *)x)));
+	return x - PAGE_OFFSET;
+}
+EXPORT_SYMBOL(__phys_addr);
  
 #endif
  
@@ -7,7 +7,7 @@
  
 #ifdef CONFIG_NUMA
  
-#define VIRTUAL_BUG_ON(x)
+#include <linux/mmdebug.h>
  
 #include <asm/smp.h>
  
@@ -64,7 +64,8 @@
 #endif
  
 #ifndef __ASSEMBLY__
-#define __phys_addr(x)		((x) - PAGE_OFFSET)
+#define __phys_addr_const(x)	((x) - PAGE_OFFSET)
+extern unsigned long __phys_addr(unsigned long);
 #define __phys_reloc_hide(x)	RELOC_HIDE((x), 0)
  
 #ifdef CONFIG_FLATMEM
@@ -7,6 +7,7 @@
  
 #include <linux/gfp.h>
 #include <linux/list.h>
+#include <linux/mmdebug.h>
 #include <linux/mmzone.h>
 #include <linux/rbtree.h>
 #include <linux/prio_tree.h>
@@ -209,12 +210,6 @@
  * files which need it (119 of them)
  */
 #include <linux/page-flags.h>
-
-#ifdef CONFIG_DEBUG_VM
-#define VM_BUG_ON(cond) BUG_ON(cond)
-#else
-#define VM_BUG_ON(condition) do { } while(0)
-#endif
  
 /*
  * Methods to modify the page usage count.
+#ifndef LINUX_MM_DEBUG_H
+#define LINUX_MM_DEBUG_H 1
+
+#include <linux/autoconf.h>
+
+#ifdef CONFIG_DEBUG_VM
+#define VM_BUG_ON(cond) BUG_ON(cond)
+#else
+#define VM_BUG_ON(cond) do { } while(0)
+#endif
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+#define VIRTUAL_BUG_ON(cond) BUG_ON(cond)
+#else
+#define VIRTUAL_BUG_ON(cond) do { } while(0)
+#endif
+
+#endif
@@ -469,6 +469,15 @@
  
 	  If unsure, say N.
  
+config DEBUG_VIRTUAL
+	bool "Debug VM translations"
+	depends on DEBUG_KERNEL && X86
+	help
+	  Enable some costly sanity checks in virtual to page code. This can
+	  catch mistakes with virt_to_page() and friends.
+
+	  If unsure, say N.
+
 config DEBUG_WRITECOUNT
 	bool "Debug filesystem writers count"
 	depends on DEBUG_KERNEL
@@ -180,6 +180,11 @@
 	pmd_t *pmd;
 	pte_t *ptep, pte;
  
+	/* XXX we might need to change this if we add VIRTUAL_BUG_ON for
+	 * architectures that do not vmalloc module space */
+	VIRTUAL_BUG_ON(!is_vmalloc_addr(vmalloc_addr) &&
+			!is_module_address(addr));
+
 	if (!pgd_none(*pgd)) {
 		pud = pud_offset(pgd, addr);
 		if (!pud_none(*pud)) {
...	...	@@ -66,7 +66,7 @@
66	66	.ds = __USER_DS,
67	67	.fs = __KERNEL_PERCPU,
68	68
69		- .__cr3 = __pa(swapper_pg_dir)
	69	+ .__cr3 = __phys_addr_const((unsigned long)swapper_pg_dir)
70	70	}
71	71	};
...	...	@@ -23,18 +23,26 @@
23	23
24	24	#ifdef CONFIG_X86_64
25	25
26		-unsigned long __phys_addr(unsigned long x)
	26	+static inline int phys_addr_valid(unsigned long addr)
27	27	{
28		- if (x >= __START_KERNEL_map)
29		- return x - __START_KERNEL_map + phys_base;
30		- return x - PAGE_OFFSET;
	28	+ return addr < (1UL << boot_cpu_data.x86_phys_bits);
31	29	}
32		-EXPORT_SYMBOL(__phys_addr);
33	30
34		-static inline int phys_addr_valid(unsigned long addr)
	31	+unsigned long __phys_addr(unsigned long x)
35	32	{
36		- return addr < (1UL << boot_cpu_data.x86_phys_bits);
	33	+ if (x >= __START_KERNEL_map) {
	34	+ x -= __START_KERNEL_map;
	35	+ VIRTUAL_BUG_ON(x >= KERNEL_IMAGE_SIZE);
	36	+ x += phys_base;
	37	+ } else {
	38	+ VIRTUAL_BUG_ON(x < PAGE_OFFSET);
	39	+ x -= PAGE_OFFSET;
	40	+ VIRTUAL_BUG_ON(system_state == SYSTEM_BOOTING ? x > MAXMEM :
	41	+ !phys_addr_valid(x));
	42	+ }
	43	+ return x;
37	44	}
	45	+EXPORT_SYMBOL(__phys_addr);
38	46
39	47	#else
40	48
...	...	@@ -42,6 +50,15 @@
42	50	{
43	51	return 1;
44	52	}
	53	+
	54	+unsigned long __phys_addr(unsigned long x)
	55	+{
	56	+ /* VMALLOC_* aren't constants; not available at the boot time */
	57	+ VIRTUAL_BUG_ON(x < PAGE_OFFSET \|\| (system_state != SYSTEM_BOOTING &&
	58	+ is_vmalloc_addr((void *)x)));
	59	+ return x - PAGE_OFFSET;
	60	+}
	61	+EXPORT_SYMBOL(__phys_addr);
45	62
46	63	#endif
47	64
...	...	@@ -7,7 +7,7 @@
7	7
8	8	#ifdef CONFIG_NUMA
9	9
10		-#define VIRTUAL_BUG_ON(x)
	10	+#include <linux/mmdebug.h>
11	11
12	12	#include <asm/smp.h>
13	13
...	...	@@ -64,7 +64,8 @@
64	64	#endif
65	65
66	66	#ifndef __ASSEMBLY__
67		-#define __phys_addr(x) ((x) - PAGE_OFFSET)
	67	+#define __phys_addr_const(x) ((x) - PAGE_OFFSET)
	68	+extern unsigned long __phys_addr(unsigned long);
68	69	#define __phys_reloc_hide(x) RELOC_HIDE((x), 0)
69	70
70	71	#ifdef CONFIG_FLATMEM
...	...	@@ -7,6 +7,7 @@
7	7
8	8	#include <linux/gfp.h>
9	9	#include <linux/list.h>
	10	+#include <linux/mmdebug.h>
10	11	#include <linux/mmzone.h>
11	12	#include <linux/rbtree.h>
12	13	#include <linux/prio_tree.h>
...	...	@@ -209,12 +210,6 @@
209	210	* files which need it (119 of them)
210	211	*/
211	212	#include <linux/page-flags.h>
212		-
213		-#ifdef CONFIG_DEBUG_VM
214		-#define VM_BUG_ON(cond) BUG_ON(cond)
215		-#else
216		-#define VM_BUG_ON(condition) do { } while(0)
217		-#endif
218	213
219	214	/*
220	215	* Methods to modify the page usage count.
	1	+#ifndef LINUX_MM_DEBUG_H
	2	+#define LINUX_MM_DEBUG_H 1
	3	+
	4	+#include <linux/autoconf.h>
	5	+
	6	+#ifdef CONFIG_DEBUG_VM
	7	+#define VM_BUG_ON(cond) BUG_ON(cond)
	8	+#else
	9	+#define VM_BUG_ON(cond) do { } while(0)
	10	+#endif
	11	+
	12	+#ifdef CONFIG_DEBUG_VIRTUAL
	13	+#define VIRTUAL_BUG_ON(cond) BUG_ON(cond)
	14	+#else
	15	+#define VIRTUAL_BUG_ON(cond) do { } while(0)
	16	+#endif
	17	+
	18	+#endif
...	...	@@ -469,6 +469,15 @@
469	469
470	470	If unsure, say N.
471	471
	472	+config DEBUG_VIRTUAL
	473	+ bool "Debug VM translations"
	474	+ depends on DEBUG_KERNEL && X86
	475	+ help
	476	+ Enable some costly sanity checks in virtual to page code. This can
	477	+ catch mistakes with virt_to_page() and friends.
	478	+
	479	+ If unsure, say N.
	480	+
472	481	config DEBUG_WRITECOUNT
473	482	bool "Debug filesystem writers count"
474	483	depends on DEBUG_KERNEL
...	...	@@ -180,6 +180,11 @@
180	180	pmd_t *pmd;
181	181	pte_t *ptep, pte;
182	182
	183	+ /* XXX we might need to change this if we add VIRTUAL_BUG_ON for
	184	+ * architectures that do not vmalloc module space */
	185	+ VIRTUAL_BUG_ON(!is_vmalloc_addr(vmalloc_addr) &&
	186	+ !is_module_address(addr));
	187	+
183	188	if (!pgd_none(*pgd)) {
184	189	pud = pud_offset(pgd, addr);
185	190	if (!pud_none(*pud)) {