From 540e9053a126c5dfc765476a458120834f396302 Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@suse.cz>
Date: Fri, 21 Jan 2022 22:14:27 -0800
Subject: lib/stackdepot: allow optional init and stack_table allocation by
kvmalloc()
Git-commit: 2dba5eb1c73b6ba2988ced07250edeac0f8cbf5a
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Currently, enabling CONFIG_STACKDEPOT means its stack_table will be
allocated from memblock, even if stack depot ends up not actually used.
The default size of stack_table is 4MB on 32-bit, 8MB on 64-bit.
This is fine for use-cases such as KASAN which is also a config option
and has overhead on its own. But it's an issue for functionality that
has to be actually enabled on boot (page_owner) or depends on hardware
(GPU drivers) and thus the memory might be wasted. This was raised as
an issue [1] when attempting to add stackdepot support for SLUB's debug
object tracking functionality. It's common to build kernels with
CONFIG_SLUB_DEBUG and enable slub_debug on boot only when needed, or
create only specific kmem caches with debugging for testing purposes.
It would thus be more efficient if stackdepot's table was allocated only
when actually going to be used. This patch thus makes the allocation
(and whole stack_depot_init() call) optional:
- Add a CONFIG_STACKDEPOT_ALWAYS_INIT flag to keep using the current
well-defined point of allocation as part of mem_init(). Make
CONFIG_KASAN select this flag.
- Other users have to call stack_depot_init() as part of their own init
when it's determined that stack depot will actually be used. This may
depend on both config and runtime conditions. Convert current users
which are page_owner and several in the DRM subsystem. Same will be
done for SLUB later.
- Because the init might now be called after the boot-time memblock
allocation has given all memory to the buddy allocator, change
stack_depot_init() to allocate stack_table with kvmalloc() when
memblock is no longer available. Also handle allocation failure by
disabling stackdepot (could have theoretically happened even with
memblock allocation previously), and don't unnecessarily align the
memblock allocation to its own size anymore.
[1] https://lore.kernel.org/all/CAMuHMdW=eoVzM1Re5FVoEN87nKfiLmM2+Ah7eNu2KXEhCvbZyA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20211013073005.11351-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Marco Elver <elver@google.com> # stackdepot
Cc: Marco Elver <elver@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Oliver Glitta <glittao@gmail.com>
Cc: Imran Khan <imran.f.khan@oracle.com>
From: Colin Ian King <colin.king@canonical.com>
*Subject: lib/stackdepot: fix spelling mistake and grammar in pr_err message
There is a spelling mistake of the work allocation so fix this and
re-phrase the message to make it easier to read.
Link: https://lkml.kernel.org/r/20211015104159.11282-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
From: Vlastimil Babka <vbabka@suse.cz>
*Subject: lib/stackdepot: allow optional init and stack_table allocation by kvmalloc() - fixup
On FLATMEM, we call page_ext_init_flatmem_late() just before
kmem_cache_init() which means stack_depot_init() (called by page owner
init) will not recognize properly it should use kvmalloc() and not
memblock_alloc(). memblock_alloc() will also not issue a warning and
return a block memory that can be invalid and cause kernel page fault when
saving stacks, as reported by the kernel test robot [1].
Fix this by moving page_ext_init_flatmem_late() below kmem_cache_init() so
that slab_is_available() is true during stack_depot_init(). SPARSEMEM
doesn't have this issue, as it doesn't do page_ext_init_flatmem_late(),
but a different page_ext_init() even later in the boot process.
Thanks to Mike Rapoport for pointing out the FLATMEM init ordering issue.
While at it, also actually resolve a checkpatch warning in stack_depot_init()
from DRM CI, which was supposed to be in the original patch already.
[1] https://lore.kernel.org/all/20211014085450.GC18719@xsang-OptiPlex-9020/
Link: https://lkml.kernel.org/r/6abd9213-19a9-6d58-cedc-2414386d2d81@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: kernel test robot <oliver.sang@intel.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
From: Vlastimil Babka <vbabka@suse.cz>
*Subject: lib/stackdepot: allow optional init and stack_table allocation by kvmalloc() - fixup3
Due to cd06ab2fd48f ("drm/locking: add backtrace for locking contended
locks without backoff") landing recently to -next adding a new stack depot
user in drivers/gpu/drm/drm_modeset_lock.c we need to add an appropriate
call to stack_depot_init() there as well.
Link: https://lkml.kernel.org/r/2a692365-cfa1-64f2-34e0-8aa5674dce5e@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Marco Elver <elver@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Oliver Glitta <glittao@gmail.com>
Cc: Imran Khan <imran.f.khan@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
From: Vlastimil Babka <vbabka@suse.cz>
*Subject: lib/stackdepot: allow optional init and stack_table allocation by kvmalloc() - fixup4
Due to 4e66934eaadc ("lib: add reference counting tracking
infrastructure") landing recently to net-next adding a new stack depot
user in lib/ref_tracker.c we need to add an appropriate call to
stack_depot_init() there as well.
Link: https://lkml.kernel.org/r/45c1b738-1a2f-5b5f-2f6d-86fab206d01c@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Cc: Jiri Slab <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 1 +
drivers/gpu/drm/drm_mm.c | 4 +++
drivers/gpu/drm/drm_modeset_lock.c | 9 +++++++
drivers/gpu/drm/i915/intel_runtime_pm.c | 3 +++
include/linux/stackdepot.h | 25 ++++++++++++-------
init/main.c | 9 ++++---
lib/Kconfig | 4 +++
lib/Kconfig.kasan | 2 +-
lib/stackdepot.c | 33 +++++++++++++++++++++----
mm/page_owner.c | 2 ++
10 files changed, 74 insertions(+), 18 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index f3d79eda94bb..8b3822142fed 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -5511,6 +5511,7 @@ int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
mutex_init(&mgr->probe_lock);
#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
mutex_init(&mgr->topology_ref_history_lock);
+ stack_depot_init();
#endif
INIT_LIST_HEAD(&mgr->tx_msg_downq);
INIT_LIST_HEAD(&mgr->destroy_port_list);
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 7d1c578388d3..8257f9d4f619 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -980,6 +980,10 @@ void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
add_hole(&mm->head_node);
mm->scan_active = 0;
+
+#ifdef CONFIG_DRM_DEBUG_MM
+ stack_depot_init();
+#endif
}
EXPORT_SYMBOL(drm_mm_init);
diff --git a/drivers/gpu/drm/drm_modeset_lock.c b/drivers/gpu/drm/drm_modeset_lock.c
index c97323365675..918065982db4 100644
--- a/drivers/gpu/drm/drm_modeset_lock.c
+++ b/drivers/gpu/drm/drm_modeset_lock.c
@@ -107,6 +107,11 @@ static void __drm_stack_depot_print(depot_stack_handle_t stack_depot)
kfree(buf);
}
+
+static void __drm_stack_depot_init(void)
+{
+ stack_depot_init();
+}
#else /* CONFIG_DRM_DEBUG_MODESET_LOCK */
static depot_stack_handle_t __drm_stack_depot_save(void)
{
@@ -115,6 +120,9 @@ static depot_stack_handle_t __drm_stack_depot_save(void)
static void __drm_stack_depot_print(depot_stack_handle_t stack_depot)
{
}
+static void __drm_stack_depot_init(void)
+{
+}
#endif /* CONFIG_DRM_DEBUG_MODESET_LOCK */
/**
@@ -359,6 +367,7 @@ void drm_modeset_lock_init(struct drm_modeset_lock *lock)
{
ww_mutex_init(&lock->mutex, &crtc_ww_class);
INIT_LIST_HEAD(&lock->head);
+ __drm_stack_depot_init();
}
EXPORT_SYMBOL(drm_modeset_lock_init);
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 22dab36afcb6..53f1ccb78849 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -68,6 +68,9 @@ static noinline depot_stack_handle_t __save_depot_stack(void)
static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
spin_lock_init(&rpm->debug.lock);
+
+ if (rpm->available)
+ stack_depot_init();
}
static noinline depot_stack_handle_t
diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h
index ddc48d9c4973..5bf52221197b 100644
--- a/include/linux/stackdepot.h
+++ b/include/linux/stackdepot.h
@@ -13,6 +13,22 @@
typedef u32 depot_stack_handle_t;
+/*
+ * Every user of stack depot has to call this during its own init when it's
+ * decided that it will be calling stack_depot_save() later.
+ *
+ * The alternative is to select STACKDEPOT_ALWAYS_INIT to have stack depot
+ * enabled as part of mm_init(), for subsystems where it's known at compile time
+ * that stack depot will be used.
+ */
+int stack_depot_init(void);
+
+#ifdef CONFIG_STACKDEPOT_ALWAYS_INIT
+static inline int stack_depot_early_init(void) { return stack_depot_init(); }
+#else
+static inline int stack_depot_early_init(void) { return 0; }
+#endif
+
depot_stack_handle_t stack_depot_save(unsigned long *entries,
unsigned int nr_entries, gfp_t gfp_flags);
@@ -26,13 +42,4 @@ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
void stack_depot_print(depot_stack_handle_t stack);
-#ifdef CONFIG_STACKDEPOT
-int stack_depot_init(void);
-#else
-static inline int stack_depot_init(void)
-{
- return 0;
-}
-#endif /* CONFIG_STACKDEPOT */
-
#endif
diff --git a/init/main.c b/init/main.c
index 8d97aba78c3a..a0a0502ec1e3 100644
--- a/init/main.c
+++ b/init/main.c
@@ -826,12 +826,15 @@ static void __init mm_init(void)
init_mem_debugging_and_hardening();
kfence_alloc_pool();
report_meminit();
- stack_depot_init();
+ stack_depot_early_init();
mem_init();
mem_init_print_info();
- /* page_owner must be initialized after buddy is ready */
- page_ext_init_flatmem_late();
kmem_cache_init();
+ /*
+ * page_owner must be initialized after buddy is ready, and also after
+ * slab is ready so that stack_depot_init() works properly
+ */
+ page_ext_init_flatmem_late();
kmemleak_init();
pgtable_init();
debug_objects_mem_init();
diff --git a/lib/Kconfig b/lib/Kconfig
index 5c9c0687f76d..1fcef8cad1f9 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -665,6 +665,10 @@ config STACKDEPOT
bool
select STACKTRACE
+config STACKDEPOT_ALWAYS_INIT
+ bool
+ select STACKDEPOT
+
config STACK_HASH_ORDER
int "stack depot hash size (12 => 4KB, 20 => 1024KB)"
range 12 20
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 1e2d10f86011..dec5f20d3609 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -38,7 +38,7 @@ menuconfig KASAN
CC_HAS_WORKING_NOSANITIZE_ADDRESS) || \
HAVE_ARCH_KASAN_HW_TAGS
depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
- select STACKDEPOT
+ select STACKDEPOT_ALWAYS_INIT
help
Enables KASAN (KernelAddressSANitizer) - runtime memory debugger,
designed to find out-of-bounds accesses and use-after-free bugs.
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 5f6c1044bf64..54a1b82b2e8f 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -24,6 +24,7 @@
#include <linux/jhash.h>
#include <linux/kernel.h>
#include <linux/mm.h>
+#include <linux/mutex.h>
#include <linux/percpu.h>
#include <linux/printk.h>
#include <linux/slab.h>
@@ -162,18 +163,40 @@ static int __init is_stack_depot_disabled(char *str)
}
early_param("stack_depot_disable", is_stack_depot_disabled);
-int __init stack_depot_init(void)
+/*
+ * __ref because of memblock_alloc(), which will not be actually called after
+ * the __init code is gone, because at that point slab_is_available() is true
+ */
+__ref int stack_depot_init(void)
{
- if (!stack_depot_disable) {
+ static DEFINE_MUTEX(stack_depot_init_mutex);
+
+ mutex_lock(&stack_depot_init_mutex);
+ if (!stack_depot_disable && !stack_table) {
size_t size = (STACK_HASH_SIZE * sizeof(struct stack_record *));
int i;
- stack_table = memblock_alloc(size, size);
- for (i = 0; i < STACK_HASH_SIZE; i++)
- stack_table[i] = NULL;
+ if (slab_is_available()) {
+ pr_info("Stack Depot allocating hash table with kvmalloc\n");
+ stack_table = kvmalloc(size, GFP_KERNEL);
+ } 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++)
+ stack_table[i] = NULL;
+ } else {
+ pr_err("Stack Depot hash table allocation failed, disabling\n");
+ stack_depot_disable = true;
+ mutex_unlock(&stack_depot_init_mutex);
+ return -ENOMEM;
+ }
}
+ mutex_unlock(&stack_depot_init_mutex);
return 0;
}
+EXPORT_SYMBOL_GPL(stack_depot_init);
/* Calculate hash for a stack */
static inline u32 hash_stack(unsigned long *entries, unsigned int size)
diff --git a/mm/page_owner.c b/mm/page_owner.c
index cba269a599bd..efbd305bf559 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -80,6 +80,8 @@ static void init_page_owner(void)
if (!page_owner_enabled)
return;
+ stack_depot_init();
+
register_dummy_stack();
register_failure_stack();
register_early_stack();
--
2.38.1