[PATCH RFC V2 0/3] KASLR feature to randomize each loadable module

[PATCH RFC V2 0/3] KASLR feature to randomize each loadable module

[Rick Edgecombe]

Hi,

This is v2 of the "KASLR feature to randomize each loadable module" patchset.
The purpose is to increase the randomization and makes the modules randomized
in relation to each other instead of just the base, so that if one module leaks,
the location of the others can't be inferred.

This code needs some refactoring and simplification, but I was hoping to get
some feedback on the benchmarks and provide an update.

V2 brings the TLB flushes down to close to the existing algorithm and increases
the modules that get high randomness based on the concerns raised by Jann Horn
about the BPF JIT use case. It also tries to address Kees Cook's comments about
possible minimal boot time regression by measuring the average allocation time
to be below the existing allocator. It also addresses Mathew Wilcox's comment
on the GFP_NOWARN not being needed. There is also some data on PTE memory use
which is higher than the original algorithm, as suggested by Jann.

This is off of 4.18-RC3.

Changes since v1:
 - New implementation of __vmalloc_node_try_addr based on the
   __vmalloc_node_range implementation, that only flushes TLB when needed.
 - Modified module loading algorithm to try to reduce the TLB flushes further.
 - Increase "random area" tries in order to increase the number of modules that
   can get high randomness.
 - Increase "random area" size to 2/3 of module area in order to increase the
   number of modules that can get high randomness.
 - Fix for 0day failures on other architectures.
 - Fix for wrong debugfs permissions. (thanks to Jann)
 - Spelling fix .(thanks to Jann)
 - Data on module_alloc performance and TLB flushes. (brought up by Kees and
   Jann)
 - Data on memory usage. (suggested by Jann)
 
Todo:
 - Refactor __vmalloc_node_try_addr to be smaller and share more code with the
   normal vmalloc path, and misc cleanup
 - More real world testing other than the synthetic micro benchmarks described
   below. BPF kselftest brought up by Daniel Borkman.

New Algorithm
=============
In addition to __vmalloc_node_try_addr only purging the lazy free areas when it
needs to, it also now supports a mode where it will fail to allocate instead of
doing any purge. In this case it reports when the allocation would have
succeeded if it was allowed to purge. It returns this information via an
ERR_PTR.

The logic for the selection of a location in the random ara is changed as well.
The number of tries is increased from 10 to 10000, which actually still gives
good performance. At a high level, the vmalloc algorithm quickly traverses an
RB-Tree to find a start position and then more slowly traverses a link list to
look for an open spot. Since this new algorithm randomly picks a spot, it
mostly just needs to traverse the RB-Tree, and as a result the "tries" are fast
enough that the number can be high and still be faster than traversing the
linked list. In the data below you can see that the random algorithm is on
average actually faster than the existing one.

The increase in number of tries is also to support the BPF JIT use case, by
increasing the number of modules that can get high randomness.

Since the __vmalloc_node_try_addr now can optionally fail instead of purging,
for the first half of the tries, the algorithm tries to find a spot where it
doesn't need to do a purge. For the second half it allows purges. The 50:50
split is to try to be a happy medium between reducing TLB flushes and reducing
average allocation time.

Randomness
==========
In the last patchset the size of the random area used in the calculations was
incorrect. The entropy should have been closer to 17 bits, not 18, which is why
its lower here even though the number of random area tries is cranked up. 17.3
bits is likely maintained to much higher number of allocations than shown here
in reality, since it seems that the BPF JIT allocations are usually smaller than
modules. If you assume the majority of allocations are 1 page, 17 bits is
maintained to 8000 modules.

Modules		Min Info
1000		17.3
2000		17.3
3000		17.3
4000		17.3
5000		17.08
6000		16.30
7000		15.67
8000		14.92

Allocation Time
===============
The average module_alloc time over N modules was actually always faster with the
random algorithm:

Modules	Existing(ns)	New(ns)
1000	4,761		1,134
2000	9,730		1,149
3000	15,572		1,396
4000	20,723		2,161
5000	26,206		4,349
6000	31,374		8,615
7000	36,123		14,009
8000	40,174		23,396

Average Nth Allocation time was usually better than the existing algorithm,
until the modules get very high.

Module	Original(ns)	New(ns)
1000	8,800		1,288
2000	20,949		1,477
3000	31,980		2,583
4000	44,539		9,250
5000	55,212		25,986
6000	65,968		39,540
7000	74,883		57,798
8000	85,392		97,319

TLB Flushes Per Allocation
==========================
The new algorithm flushes the TLB a little bit more than the existing algorithm.
For the sake of comparison to the old simpler __vmalloc_node_try_addr
implementation, this is about a 238x improvement in some cases.

Modules	Existing	New
1000	0.0014		0.001407
2000	0.001746	0.0018155
3000	0.0018186667	0.0021186667
4000	0.00187525	0.00249675
5000	0.001897	0.0025334
6000	0.0019066667	0.0025228333
7000	0.001925	0.0025315714
8000	0.0019325	0.002553

Memory Usage
============
A downside is that since the random area is fragmented, it uses extra PTE pages.
It first approaches 1.3 MB of PTEs as the random area fills. After that it
increases more slowly. I am not sure this can be improved without reducing
randomness.

Modules	Existing(pages)	New(pages)
100	6		159
200	11		240
300	15		285
400	20		307
500	23		315
1000	41		330
2000	80		335
3000	118		338

Module Capacity
===============
The estimate of module capacity also now goes back up to ~17000, so the real
value should be close to the existing algorithm.


Rick Edgecombe (3):
  vmalloc: Add __vmalloc_node_try_addr function
  x86/modules: Increase randomization for modules
  vmalloc: Add debugfs modfraginfo

 arch/x86/include/asm/pgtable_64_types.h |   1 +
 arch/x86/kernel/module.c                | 103 +++++++++++-
 include/linux/vmalloc.h                 |   3 +
 mm/vmalloc.c                            | 275 +++++++++++++++++++++++++++++++-
 4 files changed, 375 insertions(+), 7 deletions(-)

-- 
2.7.4

[PATCH 1/3] vmalloc: Add __vmalloc_node_try_addr function

[Rick Edgecombe]

Create __vmalloc_node_try_addr function that tries to allocate at a specific
address and supports caller specified behavior for whether any lazy purging
happens if there is a collision.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 include/linux/vmalloc.h |   3 +
 mm/vmalloc.c            | 174 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 177 insertions(+)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 398e9c9..c7712c8 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -82,6 +82,9 @@ extern void *__vmalloc_node_range(unsigned long size, unsigned long align,
 			unsigned long start, unsigned long end, gfp_t gfp_mask,
 			pgprot_t prot, unsigned long vm_flags, int node,
 			const void *caller);
+extern void *__vmalloc_node_try_addr(unsigned long addr, unsigned long size,
+			gfp_t gfp_mask,	pgprot_t prot, unsigned long vm_flags,
+			int node, int try_purge, const void *caller);
 #ifndef CONFIG_MMU
 extern void *__vmalloc_node_flags(unsigned long size, int node, gfp_t flags);
 static inline void *__vmalloc_node_flags_caller(unsigned long size, int node,
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index cfea25b..b6f2449 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1710,6 +1710,180 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 }
 
 /**
+ *	__vmalloc_try_addr  -  try to alloc at a specific address
+ *	@addr:		address to try
+ *	@size:		size to try
+ *	@gfp_mask:	flags for the page level allocator
+ *	@prot:		protection mask for the allocated pages
+ *	@vm_flags:	additional vm area flags (e.g. %VM_NO_GUARD)
+ *	@node:		node to use for allocation or NUMA_NO_NODE
+ *	@try_purge:	try to purge if needed to fulfill and allocation
+ *	@caller:	caller's return address
+ *
+ *	Try to allocate at the specific address. If it succeeds the address is
+ *	returned. If it fails NULL is returned. If try_purge is zero, it will
+ *	return an EBUSY ERR_PTR if it could have allocated if it was allowed to
+ *	purge. It may trigger TLB flushes if a purge is needed, and try_purge is
+ *	set.
+ */
+void *__vmalloc_node_try_addr(unsigned long addr, unsigned long size,
+			gfp_t gfp_mask,	pgprot_t prot, unsigned long vm_flags,
+			int node, int try_purge, const void *caller)
+{
+	struct vmap_area *va;
+	struct vm_struct *area;
+	struct rb_node *n;
+	struct vmap_area *cur_va = NULL;
+	struct vmap_area *first_before = NULL;
+
+	int not_at_end = 0;
+	int need_purge = 0;
+	int blocked = 0;
+	int purged = 0;
+
+	unsigned long real_size = size;
+	unsigned long addr_end;
+
+	size = PAGE_ALIGN(size);
+	if (!size || (size >> PAGE_SHIFT) > totalram_pages)
+		return NULL;
+
+	WARN_ON(in_interrupt());
+
+	va = kmalloc_node(sizeof(struct vmap_area),
+			gfp_mask & GFP_RECLAIM_MASK, node);
+	if (unlikely(!va)) {
+		warn_alloc(gfp_mask, NULL,
+			"kmalloc: allocation failure");
+		return NULL;
+	}
+
+	area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
+	if (unlikely(!area)) {
+		warn_alloc(gfp_mask, NULL,
+			"kmalloc: allocation failure");
+		goto failva;
+	}
+	/*
+	 * Only scan the relevant parts containing pointers to other objects
+	 * to avoid false negatives.
+	 */
+	kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK);
+
+	if (!(vm_flags & VM_NO_GUARD))
+		size += PAGE_SIZE;
+
+	addr_end = addr + size;
+	if (addr > addr_end)
+		return NULL;
+
+retry:
+	spin_lock(&vmap_area_lock);
+
+	n = vmap_area_root.rb_node;
+	while (n) {
+		cur_va = rb_entry(n, struct vmap_area, rb_node);
+		if (addr < cur_va->va_end) {
+			not_at_end = 1;
+			if (cur_va->va_start == addr) {
+				first_before = cur_va;
+				break;
+			}
+			n = n->rb_left;
+		} else {
+			first_before = cur_va;
+			n = n->rb_right;
+		}
+	}
+
+	/*
+	 * Linearly search through to make sure there is a hole, unless we are
+	 * at the end of the VA list.
+	 */
+	if (not_at_end) {
+		/*
+		 * If there is no VA that starts before the
+		 * target address, start the check from the closest VA.
+		 */
+		if (first_before)
+			cur_va = first_before;
+
+		while (cur_va->va_start < addr_end) {
+			if (cur_va->va_end > addr) {
+				if (cur_va->flags & VM_LAZY_FREE) {
+					need_purge = 1;
+				} else {
+					blocked = 1;
+					break;
+				}
+			}
+
+			if (list_is_last(&cur_va->list, &vmap_area_list))
+				break;
+
+			cur_va = list_next_entry(cur_va, list);
+		}
+
+		if (blocked || (!try_purge && need_purge)) {
+			/*
+			 * If a non-lazy free va blocks the allocation, or
+			 * we are not supposed to purge, but we need to the
+			 * allocation fails.
+			 */
+			goto fail;
+		}
+		if (try_purge && need_purge) {
+			if (purged) {
+				/* if purged once before, give up */
+				goto fail;
+			} else {
+				/*
+				 * If the va blocking the allocation is set to
+				 * be purged then purge all vmap_areas that are
+				 * set to purged since this will flush the TLBs
+				 * anyway.
+				 */
+				spin_unlock(&vmap_area_lock);
+				purge_vmap_area_lazy();
+				need_purge = 0;
+				purged = 1;
+				goto retry;
+			}
+		}
+	}
+
+	va->va_start = addr;
+	va->va_end = addr_end;
+	va->flags = 0;
+	__insert_vmap_area(va);
+
+	spin_unlock(&vmap_area_lock);
+
+	setup_vmalloc_vm(area, va, vm_flags, caller);
+
+	addr = (unsigned long)__vmalloc_area_node(area, gfp_mask, prot, node);
+	if (!addr) {
+		warn_alloc(gfp_mask, NULL,
+			"vmalloc: allocation failure: %lu bytes", real_size);
+		return NULL;
+	}
+
+	clear_vm_uninitialized_flag(area);
+
+	kmemleak_vmalloc(area, size, gfp_mask);
+
+	return (void *)addr;
+fail:
+	kfree(area);
+	spin_unlock(&vmap_area_lock);
+failva:
+	kfree(va);
+	if (need_purge && !blocked)
+		return ERR_PTR(-EBUSY);
+	return NULL;
+}
+
+/**
  *	__vmalloc_node_range  -  allocate virtually contiguous memory
  *	@size:		allocation size
  *	@align:		desired alignment
-- 
2.7.4

[PATCH 2/3] x86/modules: Increase randomization for modules

[Rick Edgecombe]

This changes the behavior of the KASLR logic for allocating memory for the text
sections of loadable modules. It randomizes the location of each module text
section with about 17 bits of entropy in typical use. This is enabled on X86_64
only. For 32 bit, the behavior is unchanged.

The algorithm evenly breaks the module space in two, a random area and a backup
area. For module text allocations, it first tries to allocate at a number of
randomly located starting pages inside the random section. If this fails, it
will allocate in the backup area. The backup area base will be offset in the
same way as the current algorithm does for the base area, 1024 possible
locations.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 arch/x86/include/asm/pgtable_64_types.h |   1 +
 arch/x86/kernel/module.c                | 103 ++++++++++++++++++++++++++++++--
 2 files changed, 98 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 054765a..56452a0 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -141,6 +141,7 @@ extern unsigned int ptrs_per_p4d;
 /* The module sections ends with the start of the fixmap */
 #define MODULES_END		_AC(0xffffffffff000000, UL)
 #define MODULES_LEN		(MODULES_END - MODULES_VADDR)
+#define MODULES_RAND_LEN	PAGE_ALIGN((MODULES_LEN/3)*2)
 
 #define ESPFIX_PGD_ENTRY	_AC(-2, UL)
 #define ESPFIX_BASE_ADDR	(ESPFIX_PGD_ENTRY << P4D_SHIFT)
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index f58336a..4ffff9f 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -77,6 +77,93 @@ static unsigned long int get_module_load_offset(void)
 }
 #endif
 
+static unsigned long get_module_area_base(void)
+{
+	return MODULES_VADDR + get_module_load_offset();
+}
+
+#if defined(CONFIG_X86_64) && defined(CONFIG_RANDOMIZE_BASE)
+static unsigned long get_module_vmalloc_start(void)
+{
+	if (kaslr_enabled())
+		return MODULES_VADDR + MODULES_RAND_LEN
+						+ get_module_load_offset();
+	else
+		return get_module_area_base();
+}
+
+static void *try_module_alloc(unsigned long addr, unsigned long size,
+					int try_purge)
+{
+	return __vmalloc_node_try_addr(addr, size, GFP_KERNEL,
+						PAGE_KERNEL_EXEC, 0,
+						NUMA_NO_NODE, try_purge,
+						__builtin_return_address(0));
+}
+
+/*
+ * Try to allocate in the random area. First 5000 times without purging, then
+ * 5000 times with purging. If these fail, return NULL.
+ */
+static void *try_module_randomize_each(unsigned long size)
+{
+	void *p = NULL;
+	unsigned int i;
+	unsigned long offset;
+	unsigned long addr;
+	unsigned long end;
+	unsigned long last_lazy_free_blocked = 0;
+	const unsigned long nr_mod_positions = MODULES_RAND_LEN / MODULE_ALIGN;
+	const unsigned long nr_try_purge = 5000;
+	const unsigned long nr_no_purge = 5000;
+
+	if (!kaslr_enabled())
+		return NULL;
+
+	for (i = 0; i < nr_try_purge + nr_no_purge; i++) {
+		offset = (get_random_long() % nr_mod_positions) * MODULE_ALIGN;
+		addr = (unsigned long)MODULES_VADDR + offset;
+		end = addr + size;
+
+		if (end > addr && end < MODULES_END) {
+			if (i < nr_no_purge) {
+				/* First try to avoid having to purge */
+				p = try_module_alloc(addr, size, 0);
+
+				/*
+				 * Save the last value that was blocked by a
+				 * lazy purge area
+				 */
+				if (IS_ERR(p) && PTR_ERR(p) == -EBUSY)
+					last_lazy_free_blocked = addr;
+				else if (p && !IS_ERR(p))
+					return p;
+			} else {
+				/* Give up and allow for purges */
+				if (i == nr_try_purge && last_lazy_free_blocked)
+					addr = last_lazy_free_blocked;
+
+				p = try_module_alloc(addr, size, 1);
+
+				if (p)
+					return p;
+			}
+		}
+	}
+	return NULL;
+}
+#else
+static unsigned long get_module_vmalloc_start(void)
+{
+	return get_module_area_base();
+}
+
+static void *try_module_randomize_each(unsigned long size)
+{
+	return NULL;
+}
+#endif
+
 void *module_alloc(unsigned long size)
 {
 	void *p;
@@ -84,16 +171,20 @@ void *module_alloc(unsigned long size)
 	if (PAGE_ALIGN(size) > MODULES_LEN)
 		return NULL;
 
-	p = __vmalloc_node_range(size, MODULE_ALIGN,
-				    MODULES_VADDR + get_module_load_offset(),
-				    MODULES_END, GFP_KERNEL,
-				    PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
-				    __builtin_return_address(0));
+	p = try_module_randomize_each(size);
+
+	if (!p)
+		p = __vmalloc_node_range(size, MODULE_ALIGN,
+						get_module_vmalloc_start(),
+						MODULES_END, GFP_KERNEL,
+						PAGE_KERNEL_EXEC, 0,
+						NUMA_NO_NODE,
+						__builtin_return_address(0));
+
 	if (p && (kasan_module_alloc(p, size) < 0)) {
 		vfree(p);
 		return NULL;
 	}
-
 	return p;
 }
 
-- 
2.7.4

[PATCH 3/3] vmalloc: Add debugfs modfraginfo

[Rick Edgecombe]

Add debugfs file "modfraginfo" for providing info on module space
fragmentation.  This can be used for determining if loadable module
randomization is causing any problems for extreme module loading situations,
like huge numbers of modules or extremely large modules.

Sample output when RANDOMIZE_BASE and X86_64 is configured:
Largest free space:		847253504
External Memory Fragementation:	20%
Allocations in backup area:	0

Sample output when just X86_64:
Largest free space:		847253504
External Memory Fragementation:	20%

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 mm/vmalloc.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 100 insertions(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index b6f2449..85441f2 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -18,6 +18,7 @@
 #include <linux/interrupt.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/debugfs.h>
 #include <linux/debugobjects.h>
 #include <linux/kallsyms.h>
 #include <linux/list.h>
@@ -33,6 +34,7 @@
 #include <linux/bitops.h>
 
 #include <linux/uaccess.h>
+#include <asm/setup.h>
 #include <asm/tlbflush.h>
 #include <asm/shmparam.h>
 
@@ -2922,7 +2924,104 @@ static int __init proc_vmalloc_init(void)
 		proc_create_seq("vmallocinfo", 0400, NULL, &vmalloc_op);
 	return 0;
 }
-module_init(proc_vmalloc_init);
+#else
+static int proc_vmalloc_init(void)
+{
+	return 0;
+}
+#endif
 
+#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_64)
+#if defined(CONFIG_RANDOMIZE_BASE)
+static void print_backup_area(struct seq_file *m, unsigned long backup_cnt)
+{
+	if (kaslr_enabled())
+		seq_printf(m, "Allocations in backup area:\t%lu\n", backup_cnt);
+}
+#else
+static void print_backup_area(struct seq_file *m, unsigned long backup_cnt)
+{
+}
 #endif
+static int modulefraginfo_debug_show(struct seq_file *m, void *v)
+{
+	struct list_head *i;
+	unsigned long last_end = MODULES_VADDR;
+	unsigned long total_free = 0;
+	unsigned long largest_free = 0;
+	unsigned long backup_cnt = 0;
+	unsigned long gap;
+
+	spin_lock(&vmap_area_lock);
+
+	list_for_each(i, &vmap_area_list) {
+		struct vmap_area *obj = list_entry(i, struct vmap_area, list);
+
+		if (!(obj->flags & VM_LAZY_FREE)
+			&& obj->va_start >= MODULES_VADDR
+			&& obj->va_end <= MODULES_END) {
+
+			if (obj->va_start >= MODULES_VADDR + MODULES_RAND_LEN)
+				backup_cnt++;
+
+			gap = (obj->va_start - last_end);
+			if (gap > largest_free)
+				largest_free = gap;
+			total_free += gap;
+
+			last_end = obj->va_end;
+		}
+	}
+
+	gap = (MODULES_END - last_end);
+	if (gap > largest_free)
+		largest_free = gap;
+	total_free += gap;
+
+	spin_unlock(&vmap_area_lock);
 
+	seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
+	if (total_free)
+		seq_printf(m, "External Memory Fragmentation:\t%lu%%\n",
+			100-(100*largest_free/total_free));
+	else
+		seq_puts(m, "External Memory Fragmentation:\t0%%\n");
+
+	print_backup_area(m, backup_cnt);
+
+	return 0;
+}
+
+static int proc_module_frag_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, modulefraginfo_debug_show, NULL);
+}
+
+static const struct file_operations debug_module_frag_operations = {
+	.open       = proc_module_frag_debug_open,
+	.read       = seq_read,
+	.llseek     = seq_lseek,
+	.release    = single_release,
+};
+
+static void debug_modfrag_init(void)
+{
+	debugfs_create_file("modfraginfo", 0400, NULL, NULL,
+			&debug_module_frag_operations);
+}
+#else /* defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_64) */
+static void debug_modfrag_init(void)
+{
+}
+#endif
+
+#if defined(CONFIG_DEBUG_FS) || defined(CONFIG_PROC_FS)
+static int __init info_vmalloc_init(void)
+{
+	proc_vmalloc_init();
+	debug_modfrag_init();
+	return 0;
+}
+
+module_init(info_vmalloc_init);
+#endif
-- 
2.7.4

Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3167 bytes --]

Hi Rick,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.18-rc5]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Rick-Edgecombe/KASLR-feature-to-randomize-each-loadable-module/20180707-083637
config: um-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=um 

All errors (new ones prefixed by >>):

   mm/vmalloc.c: In function 'modulefraginfo_debug_show':
>> mm/vmalloc.c:2964:41: error: 'MODULES_RAND_LEN' undeclared (first use in this function); did you mean 'MODULE_NAME_LEN'?
       if (obj->va_start >= MODULES_VADDR + MODULES_RAND_LEN)
                                            ^~~~~~~~~~~~~~~~
                                            MODULE_NAME_LEN
   mm/vmalloc.c:2964:41: note: each undeclared identifier is reported only once for each function it appears in

vim +2964 mm/vmalloc.c

  2933	
  2934	#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_64)
  2935	#if defined(CONFIG_RANDOMIZE_BASE)
  2936	static void print_backup_area(struct seq_file *m, unsigned long backup_cnt)
  2937	{
  2938		if (kaslr_enabled())
  2939			seq_printf(m, "Allocations in backup area:\t%lu\n", backup_cnt);
  2940	}
  2941	#else
  2942	static void print_backup_area(struct seq_file *m, unsigned long backup_cnt)
  2943	{
  2944	}
  2945	#endif
  2946	static int modulefraginfo_debug_show(struct seq_file *m, void *v)
  2947	{
  2948		struct list_head *i;
  2949		unsigned long last_end = MODULES_VADDR;
  2950		unsigned long total_free = 0;
  2951		unsigned long largest_free = 0;
  2952		unsigned long backup_cnt = 0;
  2953		unsigned long gap;
  2954	
  2955		spin_lock(&vmap_area_lock);
  2956	
  2957		list_for_each(i, &vmap_area_list) {
  2958			struct vmap_area *obj = list_entry(i, struct vmap_area, list);
  2959	
  2960			if (!(obj->flags & VM_LAZY_FREE)
  2961				&& obj->va_start >= MODULES_VADDR
  2962				&& obj->va_end <= MODULES_END) {
  2963	
> 2964				if (obj->va_start >= MODULES_VADDR + MODULES_RAND_LEN)
  2965					backup_cnt++;
  2966	
  2967				gap = (obj->va_start - last_end);
  2968				if (gap > largest_free)
  2969					largest_free = gap;
  2970				total_free += gap;
  2971	
  2972				last_end = obj->va_end;
  2973			}
  2974		}
  2975	
  2976		gap = (MODULES_END - last_end);
  2977		if (gap > largest_free)
  2978			largest_free = gap;
  2979		total_free += gap;
  2980	
  2981		spin_unlock(&vmap_area_lock);
  2982	
  2983		seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
  2984		if (total_free)
  2985			seq_printf(m, "External Memory Fragmentation:\t%lu%%\n",
  2986				100-(100*largest_free/total_free));
  2987		else
  2988			seq_puts(m, "External Memory Fragmentation:\t0%%\n");
  2989	
  2990		print_backup_area(m, backup_cnt);
  2991	
  2992		return 0;
  2993	}
  2994	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
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Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3167 bytes --]

Hi Rick,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.18-rc5]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Rick-Edgecombe/KASLR-feature-to-randomize-each-loadable-module/20180707-083637
config: um-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=um 

All errors (new ones prefixed by >>):

   mm/vmalloc.c: In function 'modulefraginfo_debug_show':
>> mm/vmalloc.c:2964:41: error: 'MODULES_RAND_LEN' undeclared (first use in this function); did you mean 'MODULE_NAME_LEN'?
       if (obj->va_start >= MODULES_VADDR + MODULES_RAND_LEN)
                                            ^~~~~~~~~~~~~~~~
                                            MODULE_NAME_LEN
   mm/vmalloc.c:2964:41: note: each undeclared identifier is reported only once for each function it appears in

vim +2964 mm/vmalloc.c

  2933	
  2934	#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_64)
  2935	#if defined(CONFIG_RANDOMIZE_BASE)
  2936	static void print_backup_area(struct seq_file *m, unsigned long backup_cnt)
  2937	{
  2938		if (kaslr_enabled())
  2939			seq_printf(m, "Allocations in backup area:\t%lu\n", backup_cnt);
  2940	}
  2941	#else
  2942	static void print_backup_area(struct seq_file *m, unsigned long backup_cnt)
  2943	{
  2944	}
  2945	#endif
  2946	static int modulefraginfo_debug_show(struct seq_file *m, void *v)
  2947	{
  2948		struct list_head *i;
  2949		unsigned long last_end = MODULES_VADDR;
  2950		unsigned long total_free = 0;
  2951		unsigned long largest_free = 0;
  2952		unsigned long backup_cnt = 0;
  2953		unsigned long gap;
  2954	
  2955		spin_lock(&vmap_area_lock);
  2956	
  2957		list_for_each(i, &vmap_area_list) {
  2958			struct vmap_area *obj = list_entry(i, struct vmap_area, list);
  2959	
  2960			if (!(obj->flags & VM_LAZY_FREE)
  2961				&& obj->va_start >= MODULES_VADDR
  2962				&& obj->va_end <= MODULES_END) {
  2963	
> 2964				if (obj->va_start >= MODULES_VADDR + MODULES_RAND_LEN)
  2965					backup_cnt++;
  2966	
  2967				gap = (obj->va_start - last_end);
  2968				if (gap > largest_free)
  2969					largest_free = gap;
  2970				total_free += gap;
  2971	
  2972				last_end = obj->va_end;
  2973			}
  2974		}
  2975	
  2976		gap = (MODULES_END - last_end);
  2977		if (gap > largest_free)
  2978			largest_free = gap;
  2979		total_free += gap;
  2980	
  2981		spin_unlock(&vmap_area_lock);
  2982	
  2983		seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
  2984		if (total_free)
  2985			seq_printf(m, "External Memory Fragmentation:\t%lu%%\n",
  2986				100-(100*largest_free/total_free));
  2987		else
  2988			seq_puts(m, "External Memory Fragmentation:\t0%%\n");
  2989	
  2990		print_backup_area(m, backup_cnt);
  2991	
  2992		return 0;
  2993	}
  2994	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 19863 bytes --]

Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[Edgecombe, Rick P]

On Thu, 2018-06-21 at 14:32 +0200, Jann Horn wrote:
> On Thu, Jun 21, 2018 at 12:12 AM Rick Edgecombe
> <rick.p.edgecombe@intel.com> wrote:
> > 
> > Add debugfs file "modfraginfo" for providing info on module space
> > fragmentation.  This can be used for determining if loadable module
> > randomization is causing any problems for extreme module loading
> > situations,
> > like huge numbers of modules or extremely large modules.
> > 
> > Sample output when RANDOMIZE_BASE and X86_64 is configured:
> > Largest free space:             847253504
> > External Memory Fragementation: 20%
> > Allocations in backup area:     0
> > 
> > Sample output otherwise:
> > Largest free space:             847253504
> > External Memory Fragementation: 20%
> [...]
> > 
> > +       seq_printf(m, "Largest free space:\t\t%lu\n",
> > largest_free);
> > +       if (total_free)
> > +               seq_printf(m, "External Memory
> > Fragementation:\t%lu%%\n",
> "Fragmentation"
> 
> > 
> > +                       100-(100*largest_free/total_free));
> > +       else
> > +               seq_puts(m, "External Memory
> > Fragementation:\t0%%\n");
> "Fragmentation"

Oops! Thanks.

> [...]
> > 
> > +static const struct file_operations debug_module_frag_operations =
> > {
> > +       .open       = proc_module_frag_debug_open,
> > +       .read       = seq_read,
> > +       .llseek     = seq_lseek,
> > +       .release    = single_release,
> > +};
> > 
> > +static void debug_modfrag_init(void)
> > +{
> > +       debugfs_create_file("modfraginfo", 0x0400, NULL, NULL,
> > +                       &debug_module_frag_operations);
> 0x0400 is 02000, which is the setgid bit. I think you meant to type
> 0400?

Yes, thanks.

Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[Edgecombe, Rick P]

On Thu, 2018-06-21 at 14:32 +0200, Jann Horn wrote:
> On Thu, Jun 21, 2018 at 12:12 AM Rick Edgecombe
> <rick.p.edgecombe@intel.com> wrote:
> > 
> > Add debugfs file "modfraginfo" for providing info on module space
> > fragmentation.  This can be used for determining if loadable module
> > randomization is causing any problems for extreme module loading
> > situations,
> > like huge numbers of modules or extremely large modules.
> > 
> > Sample output when RANDOMIZE_BASE and X86_64 is configured:
> > Largest free space:             847253504
> > External Memory Fragementation: 20%
> > Allocations in backup area:     0
> > 
> > Sample output otherwise:
> > Largest free space:             847253504
> > External Memory Fragementation: 20%
> [...]
> > 
> > +       seq_printf(m, "Largest free space:\t\t%lu\n",
> > largest_free);
> > +       if (total_free)
> > +               seq_printf(m, "External Memory
> > Fragementation:\t%lu%%\n",
> "Fragmentation"
> 
> > 
> > +                       100-(100*largest_free/total_free));
> > +       else
> > +               seq_puts(m, "External Memory
> > Fragementation:\t0%%\n");
> "Fragmentation"

Oops! Thanks.

> [...]
> > 
> > +static const struct file_operations debug_module_frag_operations =
> > {
> > +       .open       = proc_module_frag_debug_open,
> > +       .read       = seq_read,
> > +       .llseek     = seq_lseek,
> > +       .release    = single_release,
> > +};
> > 
> > +static void debug_modfrag_init(void)
> > +{
> > +       debugfs_create_file("modfraginfo", 0x0400, NULL, NULL,
> > +                       &debug_module_frag_operations);
> 0x0400 is 02000, which is the setgid bit. I think you meant to type
> 0400?

Yes, thanks.

Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[Jann Horn]

On Thu, Jun 21, 2018 at 12:12 AM Rick Edgecombe
<rick.p.edgecombe@intel.com> wrote:
> Add debugfs file "modfraginfo" for providing info on module space
> fragmentation.  This can be used for determining if loadable module
> randomization is causing any problems for extreme module loading situations,
> like huge numbers of modules or extremely large modules.
>
> Sample output when RANDOMIZE_BASE and X86_64 is configured:
> Largest free space:             847253504
> External Memory Fragementation: 20%
> Allocations in backup area:     0
>
> Sample output otherwise:
> Largest free space:             847253504
> External Memory Fragementation: 20%
[...]
> +       seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
> +       if (total_free)
> +               seq_printf(m, "External Memory Fragementation:\t%lu%%\n",

"Fragmentation"

> +                       100-(100*largest_free/total_free));
> +       else
> +               seq_puts(m, "External Memory Fragementation:\t0%%\n");

"Fragmentation"

[...]
> +static const struct file_operations debug_module_frag_operations = {
> +       .open       = proc_module_frag_debug_open,
> +       .read       = seq_read,
> +       .llseek     = seq_lseek,
> +       .release    = single_release,
> +};
>
> +static void debug_modfrag_init(void)
> +{
> +       debugfs_create_file("modfraginfo", 0x0400, NULL, NULL,
> +                       &debug_module_frag_operations);

0x0400 is 02000, which is the setgid bit. I think you meant to type 0400?

Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3152 bytes --]

Hi Rick,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on mmotm/master]
[also build test ERROR on v4.18-rc1 next-20180620]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Rick-Edgecombe/KASLR-feature-to-randomize-each-loadable-module/20180621-061051
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: parisc-c3000_defconfig (attached as .config)
compiler: hppa-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=parisc 

All errors (new ones prefixed by >>):

   mm/vmalloc.c: In function 'modulefraginfo_debug_show':
>> mm/vmalloc.c:2821:27: error: 'MODULES_VADDR' undeclared (first use in this function); did you mean 'MODULE_AUTHOR'?
     unsigned long last_end = MODULES_VADDR;
                              ^~~~~~~~~~~~~
                              MODULE_AUTHOR
   mm/vmalloc.c:2821:27: note: each undeclared identifier is reported only once for each function it appears in
   mm/vmalloc.c:2834:22: error: 'MODULES_END' undeclared (first use in this function); did you mean 'MODULES_VADDR'?
       && obj->va_end <= MODULES_END) {
                         ^~~~~~~~~~~
                         MODULES_VADDR

vim +2821 mm/vmalloc.c

  2817	
  2818	static int modulefraginfo_debug_show(struct seq_file *m, void *v)
  2819	{
  2820		struct list_head *i;
> 2821		unsigned long last_end = MODULES_VADDR;
  2822		unsigned long total_free = 0;
  2823		unsigned long largest_free = 0;
  2824		unsigned long backup_cnt = 0;
  2825		unsigned long gap;
  2826	
  2827		spin_lock(&vmap_area_lock);
  2828	
  2829		list_for_each(i, &vmap_area_list) {
  2830			struct vmap_area *obj = list_entry(i, struct vmap_area, list);
  2831	
  2832			if (!(obj->flags & VM_LAZY_FREE)
  2833				&& obj->va_start >= MODULES_VADDR
  2834				&& obj->va_end <= MODULES_END) {
  2835	
  2836				if (obj->va_start >= get_backup_start())
  2837					backup_cnt++;
  2838	
  2839				gap = (obj->va_start - last_end);
  2840				if (gap > largest_free)
  2841					largest_free = gap;
  2842				total_free += gap;
  2843	
  2844				last_end = obj->va_end;
  2845			}
  2846		}
  2847	
  2848		gap = (MODULES_END - last_end);
  2849		if (gap > largest_free)
  2850			largest_free = gap;
  2851		total_free += gap;
  2852	
  2853		spin_unlock(&vmap_area_lock);
  2854	
  2855		seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
  2856		if (total_free)
  2857			seq_printf(m, "External Memory Fragementation:\t%lu%%\n",
  2858				100-(100*largest_free/total_free));
  2859		else
  2860			seq_puts(m, "External Memory Fragementation:\t0%%\n");
  2861	
  2862		print_backup_area(m, backup_cnt);
  2863	
  2864		return 0;
  2865	}
  2866	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 14543 bytes --]

Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3152 bytes --]

Hi Rick,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on mmotm/master]
[also build test ERROR on v4.18-rc1 next-20180620]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Rick-Edgecombe/KASLR-feature-to-randomize-each-loadable-module/20180621-061051
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: parisc-c3000_defconfig (attached as .config)
compiler: hppa-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=parisc 

All errors (new ones prefixed by >>):

   mm/vmalloc.c: In function 'modulefraginfo_debug_show':
>> mm/vmalloc.c:2821:27: error: 'MODULES_VADDR' undeclared (first use in this function); did you mean 'MODULE_AUTHOR'?
     unsigned long last_end = MODULES_VADDR;
                              ^~~~~~~~~~~~~
                              MODULE_AUTHOR
   mm/vmalloc.c:2821:27: note: each undeclared identifier is reported only once for each function it appears in
   mm/vmalloc.c:2834:22: error: 'MODULES_END' undeclared (first use in this function); did you mean 'MODULES_VADDR'?
       && obj->va_end <= MODULES_END) {
                         ^~~~~~~~~~~
                         MODULES_VADDR

vim +2821 mm/vmalloc.c

  2817	
  2818	static int modulefraginfo_debug_show(struct seq_file *m, void *v)
  2819	{
  2820		struct list_head *i;
> 2821		unsigned long last_end = MODULES_VADDR;
  2822		unsigned long total_free = 0;
  2823		unsigned long largest_free = 0;
  2824		unsigned long backup_cnt = 0;
  2825		unsigned long gap;
  2826	
  2827		spin_lock(&vmap_area_lock);
  2828	
  2829		list_for_each(i, &vmap_area_list) {
  2830			struct vmap_area *obj = list_entry(i, struct vmap_area, list);
  2831	
  2832			if (!(obj->flags & VM_LAZY_FREE)
  2833				&& obj->va_start >= MODULES_VADDR
  2834				&& obj->va_end <= MODULES_END) {
  2835	
  2836				if (obj->va_start >= get_backup_start())
  2837					backup_cnt++;
  2838	
  2839				gap = (obj->va_start - last_end);
  2840				if (gap > largest_free)
  2841					largest_free = gap;
  2842				total_free += gap;
  2843	
  2844				last_end = obj->va_end;
  2845			}
  2846		}
  2847	
  2848		gap = (MODULES_END - last_end);
  2849		if (gap > largest_free)
  2850			largest_free = gap;
  2851		total_free += gap;
  2852	
  2853		spin_unlock(&vmap_area_lock);
  2854	
  2855		seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
  2856		if (total_free)
  2857			seq_printf(m, "External Memory Fragementation:\t%lu%%\n",
  2858				100-(100*largest_free/total_free));
  2859		else
  2860			seq_puts(m, "External Memory Fragementation:\t0%%\n");
  2861	
  2862		print_backup_area(m, backup_cnt);
  2863	
  2864		return 0;
  2865	}
  2866	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 14543 bytes --]

Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3149 bytes --]

Hi Rick,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on mmotm/master]
[also build test ERROR on v4.18-rc1 next-20180620]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Rick-Edgecombe/KASLR-feature-to-randomize-each-loadable-module/20180621-061051
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: mips-fuloong2e_defconfig (attached as .config)
compiler: mips64el-linux-gnuabi64-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=mips 

All errors (new ones prefixed by >>):

   mm/vmalloc.c: In function 'modulefraginfo_debug_show':
>> mm/vmalloc.c:2821:27: error: 'MODULES_VADDR' undeclared (first use in this function); did you mean 'MODULE_END'?
     unsigned long last_end = MODULES_VADDR;
                              ^~~~~~~~~~~~~
                              MODULE_END
   mm/vmalloc.c:2821:27: note: each undeclared identifier is reported only once for each function it appears in
>> mm/vmalloc.c:2834:22: error: 'MODULES_END' undeclared (first use in this function); did you mean 'MODULE_END'?
       && obj->va_end <= MODULES_END) {
                         ^~~~~~~~~~~
                         MODULE_END

vim +2821 mm/vmalloc.c

  2817	
  2818	static int modulefraginfo_debug_show(struct seq_file *m, void *v)
  2819	{
  2820		struct list_head *i;
> 2821		unsigned long last_end = MODULES_VADDR;
  2822		unsigned long total_free = 0;
  2823		unsigned long largest_free = 0;
  2824		unsigned long backup_cnt = 0;
  2825		unsigned long gap;
  2826	
  2827		spin_lock(&vmap_area_lock);
  2828	
  2829		list_for_each(i, &vmap_area_list) {
  2830			struct vmap_area *obj = list_entry(i, struct vmap_area, list);
  2831	
  2832			if (!(obj->flags & VM_LAZY_FREE)
  2833				&& obj->va_start >= MODULES_VADDR
> 2834				&& obj->va_end <= MODULES_END) {
  2835	
  2836				if (obj->va_start >= get_backup_start())
  2837					backup_cnt++;
  2838	
  2839				gap = (obj->va_start - last_end);
  2840				if (gap > largest_free)
  2841					largest_free = gap;
  2842				total_free += gap;
  2843	
  2844				last_end = obj->va_end;
  2845			}
  2846		}
  2847	
  2848		gap = (MODULES_END - last_end);
  2849		if (gap > largest_free)
  2850			largest_free = gap;
  2851		total_free += gap;
  2852	
  2853		spin_unlock(&vmap_area_lock);
  2854	
  2855		seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
  2856		if (total_free)
  2857			seq_printf(m, "External Memory Fragementation:\t%lu%%\n",
  2858				100-(100*largest_free/total_free));
  2859		else
  2860			seq_puts(m, "External Memory Fragementation:\t0%%\n");
  2861	
  2862		print_backup_area(m, backup_cnt);
  2863	
  2864		return 0;
  2865	}
  2866	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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Re: [PATCH 3/3] vmalloc: Add debugfs modfraginfo

[kbuild test robot]

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Hi Rick,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on mmotm/master]
[also build test ERROR on v4.18-rc1 next-20180620]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Rick-Edgecombe/KASLR-feature-to-randomize-each-loadable-module/20180621-061051
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: mips-fuloong2e_defconfig (attached as .config)
compiler: mips64el-linux-gnuabi64-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=mips 

All errors (new ones prefixed by >>):

   mm/vmalloc.c: In function 'modulefraginfo_debug_show':
>> mm/vmalloc.c:2821:27: error: 'MODULES_VADDR' undeclared (first use in this function); did you mean 'MODULE_END'?
     unsigned long last_end = MODULES_VADDR;
                              ^~~~~~~~~~~~~
                              MODULE_END
   mm/vmalloc.c:2821:27: note: each undeclared identifier is reported only once for each function it appears in
>> mm/vmalloc.c:2834:22: error: 'MODULES_END' undeclared (first use in this function); did you mean 'MODULE_END'?
       && obj->va_end <= MODULES_END) {
                         ^~~~~~~~~~~
                         MODULE_END

vim +2821 mm/vmalloc.c

  2817	
  2818	static int modulefraginfo_debug_show(struct seq_file *m, void *v)
  2819	{
  2820		struct list_head *i;
> 2821		unsigned long last_end = MODULES_VADDR;
  2822		unsigned long total_free = 0;
  2823		unsigned long largest_free = 0;
  2824		unsigned long backup_cnt = 0;
  2825		unsigned long gap;
  2826	
  2827		spin_lock(&vmap_area_lock);
  2828	
  2829		list_for_each(i, &vmap_area_list) {
  2830			struct vmap_area *obj = list_entry(i, struct vmap_area, list);
  2831	
  2832			if (!(obj->flags & VM_LAZY_FREE)
  2833				&& obj->va_start >= MODULES_VADDR
> 2834				&& obj->va_end <= MODULES_END) {
  2835	
  2836				if (obj->va_start >= get_backup_start())
  2837					backup_cnt++;
  2838	
  2839				gap = (obj->va_start - last_end);
  2840				if (gap > largest_free)
  2841					largest_free = gap;
  2842				total_free += gap;
  2843	
  2844				last_end = obj->va_end;
  2845			}
  2846		}
  2847	
  2848		gap = (MODULES_END - last_end);
  2849		if (gap > largest_free)
  2850			largest_free = gap;
  2851		total_free += gap;
  2852	
  2853		spin_unlock(&vmap_area_lock);
  2854	
  2855		seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
  2856		if (total_free)
  2857			seq_printf(m, "External Memory Fragementation:\t%lu%%\n",
  2858				100-(100*largest_free/total_free));
  2859		else
  2860			seq_puts(m, "External Memory Fragementation:\t0%%\n");
  2861	
  2862		print_backup_area(m, backup_cnt);
  2863	
  2864		return 0;
  2865	}
  2866	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
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[PATCH 3/3] vmalloc: Add debugfs modfraginfo

[Rick Edgecombe]

Add debugfs file "modfraginfo" for providing info on module space
fragmentation.  This can be used for determining if loadable module
randomization is causing any problems for extreme module loading situations,
like huge numbers of modules or extremely large modules.

Sample output when RANDOMIZE_BASE and X86_64 is configured:
Largest free space:		847253504
External Memory Fragementation:	20%
Allocations in backup area:	0

Sample output otherwise:
Largest free space:		847253504
External Memory Fragementation:	20%

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 mm/vmalloc.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 109 insertions(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 9e0820c9..afb8fe9 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -18,6 +18,7 @@
 #include <linux/interrupt.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
+#include <linux/debugfs.h>
 #include <linux/debugobjects.h>
 #include <linux/kallsyms.h>
 #include <linux/list.h>
@@ -33,6 +34,7 @@
 #include <linux/bitops.h>
 
 #include <linux/uaccess.h>
+#include <asm/setup.h>
 #include <asm/tlbflush.h>
 #include <asm/shmparam.h>
 
@@ -2785,7 +2787,113 @@ static int __init proc_vmalloc_init(void)
 		proc_create_seq("vmallocinfo", 0400, NULL, &vmalloc_op);
 	return 0;
 }
-module_init(proc_vmalloc_init);
+#else
+static int proc_vmalloc_init(void)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_DEBUG_FS
+#if defined(CONFIG_RANDOMIZE_BASE) && defined(CONFIG_X86_64)
+static void print_backup_area(struct seq_file *m, unsigned long backup_cnt)
+{
+	if (kaslr_enabled())
+		seq_printf(m, "Allocations in backup area:\t%lu\n", backup_cnt);
+}
+static unsigned long get_backup_start(void)
+{
+	return MODULES_VADDR + MODULES_RAND_LEN;
+}
+#else
+static void print_backup_area(struct seq_file *m, unsigned long backup_cnt)
+{
+}
+static unsigned long get_backup_start(void)
+{
+	return 0;
+}
+#endif
+
+static int modulefraginfo_debug_show(struct seq_file *m, void *v)
+{
+	struct list_head *i;
+	unsigned long last_end = MODULES_VADDR;
+	unsigned long total_free = 0;
+	unsigned long largest_free = 0;
+	unsigned long backup_cnt = 0;
+	unsigned long gap;
+
+	spin_lock(&vmap_area_lock);
+
+	list_for_each(i, &vmap_area_list) {
+		struct vmap_area *obj = list_entry(i, struct vmap_area, list);
+
+		if (!(obj->flags & VM_LAZY_FREE)
+			&& obj->va_start >= MODULES_VADDR
+			&& obj->va_end <= MODULES_END) {
+
+			if (obj->va_start >= get_backup_start())
+				backup_cnt++;
+
+			gap = (obj->va_start - last_end);
+			if (gap > largest_free)
+				largest_free = gap;
+			total_free += gap;
+
+			last_end = obj->va_end;
+		}
+	}
+
+	gap = (MODULES_END - last_end);
+	if (gap > largest_free)
+		largest_free = gap;
+	total_free += gap;
+
+	spin_unlock(&vmap_area_lock);
+
+	seq_printf(m, "Largest free space:\t\t%lu\n", largest_free);
+	if (total_free)
+		seq_printf(m, "External Memory Fragementation:\t%lu%%\n",
+			100-(100*largest_free/total_free));
+	else
+		seq_puts(m, "External Memory Fragementation:\t0%%\n");
+
+	print_backup_area(m, backup_cnt);
+
+	return 0;
+}
+
+static int proc_module_frag_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, modulefraginfo_debug_show, NULL);
+}
+
+static const struct file_operations debug_module_frag_operations = {
+	.open       = proc_module_frag_debug_open,
+	.read       = seq_read,
+	.llseek     = seq_lseek,
+	.release    = single_release,
+};
 
+static void debug_modfrag_init(void)
+{
+	debugfs_create_file("modfraginfo", 0x0400, NULL, NULL,
+			&debug_module_frag_operations);
+}
+#else
+static void debug_modfrag_init(void)
+{
+}
 #endif
 
+#if defined(CONFIG_DEBUG_FS) || defined(CONFIG_PROC_FS)
+static int __init info_vmalloc_init(void)
+{
+	proc_vmalloc_init();
+	debug_modfrag_init();
+	return 0;
+}
+
+module_init(info_vmalloc_init);
+#endif
-- 
2.7.4