The patch titled
Subject: lib/stackdepot: use page allocator if both slab and memblock is unavailable
has been added to the -mm tree. Its filename is
lib-stackdepot-use-page-allocator-if-both-slab-and-memblock-is-unavailable.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/lib-stackdepot-use-page-allocator-if-both-slab-and-memblock-is-unavailable.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/lib-stackdepot-use-page-allocator-if-both-slab-and-memblock-is-unavailable.patch
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------------------------------------------------------
From: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Subject: lib/stackdepot: use page allocator if both slab and memblock is unavailable
After commit 2dba5eb1c73b ("lib/stackdepot: allow optional init and
stack_table allocation by kvmalloc()"), stack_depot_init() is called later
if CONFIG_STACKDEPOT_ALWAYS_INIT=n to remove unnecessary memory usage. It
allocates stack_table using memblock_alloc() or kvmalloc() depending on
availability of slab allocator.
But when stack_depot_init() is called while creating boot slab caches,
both slab allocator and memblock is not available. So kernel crashes.
Allocate stack_table from page allocator when both slab allocator and
memblock is unavailable.
Limit size of stack_table when using page allocator because vmalloc() is
also unavailable in kmem_cache_init(). It must not be larger than
(PAGE_SIZE << (MAX_ORDER - 1)).
This patch was tested on both CONFIG_STACKDEPOT_ALWAYS_INIT=y and n.
[lkp@xxxxxxxxx: fix W=1 build warning]
Link: https://lkml.kernel.org/r/YhtDCoHWsF11rwze@xxxxxxxxxxxxxxxxxxx-northeast-1.compute.internal
Fixes: 2dba5eb1c73b ("lib/stackdepot: allow optional init and stack_table allocation by kvmalloc()")
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Oliver Glitta <glittao@xxxxxxxxx>
Cc: Faiyaz Mohammed <faiyazm@xxxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Cc: Johannes Berg <johannes.berg@xxxxxxxxx>
Cc: Yury Norov <yury.norov@xxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Matteo Croce <mcroce@xxxxxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Imran Khan <imran.f.khan@xxxxxxxxxx>
Cc: Zqiang <qiang.zhang@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/stackdepot.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
--- a/lib/stackdepot.c~lib-stackdepot-use-page-allocator-if-both-slab-and-memblock-is-unavailable
+++ a/lib/stackdepot.c
@@ -73,6 +73,14 @@ static int next_slab_inited;
static size_t depot_offset;
static DEFINE_RAW_SPINLOCK(depot_lock);
+static size_t stack_hash_size = (1 << CONFIG_STACK_HASH_ORDER);
+static inline size_t stack_hash_mask(void)
+{
+ return stack_hash_size - 1;
+}
+
+#define STACK_HASH_SEED 0x9747b28c
+
static bool init_stack_slab(void **prealloc)
{
if (!*prealloc)
@@ -142,10 +150,6 @@ depot_alloc_stack(unsigned long *entries
return stack;
}
-#define STACK_HASH_SIZE (1L << CONFIG_STACK_HASH_ORDER)
-#define STACK_HASH_MASK (STACK_HASH_SIZE - 1)
-#define STACK_HASH_SEED 0x9747b28c
-
static bool stack_depot_disable;
static struct stack_record **stack_table;
@@ -172,18 +176,28 @@ __ref int stack_depot_init(void)
mutex_lock(&stack_depot_init_mutex);
if (!stack_depot_disable && !stack_table) {
- size_t size = (STACK_HASH_SIZE * sizeof(struct stack_record *));
+ size_t size = (stack_hash_size * sizeof(struct stack_record *));
int i;
if (slab_is_available()) {
pr_info("Stack Depot allocating hash table with kvmalloc\n");
stack_table = kvmalloc(size, GFP_KERNEL);
+ } else if (totalram_pages() > 0) {
+ /* Reduce size because vmalloc may be unavailable */
+ size = min_t(size_t, size, PAGE_SIZE << (MAX_ORDER - 1));
+ stack_hash_size = size / sizeof(struct stack_record *);
+
+ pr_info("Stack Depot allocating hash table with __get_free_pages\n");
+ stack_table = (struct stack_record **)
+ __get_free_pages(GFP_KERNEL, get_order(size));
} else {
pr_info("Stack Depot allocating hash table with memblock_alloc\n");
stack_table = memblock_alloc(size, SMP_CACHE_BYTES);
}
+
if (stack_table) {
- for (i = 0; i < STACK_HASH_SIZE; i++)
+ pr_info("Stack Depot hash table size=%zu\n", stack_hash_size);
+ for (i = 0; i < stack_hash_size; i++)
stack_table[i] = NULL;
} else {
pr_err("Stack Depot hash table allocation failed, disabling\n");
@@ -363,7 +377,7 @@ depot_stack_handle_t __stack_depot_save(
goto fast_exit;
hash = hash_stack(entries, nr_entries);
- bucket = &stack_table[hash & STACK_HASH_MASK];
+ bucket = &stack_table[hash & stack_hash_mask()];
/*
* Fast path: look the stack trace up without locking.
_
Patches currently in -mm which might be from 42.hyeyoo@xxxxxxxxx are
lib-stackdepot-use-page-allocator-if-both-slab-and-memblock-is-unavailable.patch
