The patch titled
Subject: lib/stackdepot: add depot_fetch_stack helper
has been added to the -mm mm-unstable branch. Its filename is
lib-stackdepot-add-depot_fetch_stack-helper.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-stackdepot-add-depot_fetch_stack-helper.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: lib/stackdepot: add depot_fetch_stack helper
Date: Mon, 20 Nov 2023 18:47:03 +0100
Add a helper depot_fetch_stack function that fetches the pointer to a
stack record.
With this change, all static depot_* functions now operate on stack pools
and the exported stack_depot_* functions operate on the hash table.
Link: https://lkml.kernel.org/r/170d8c202f29dc8e3d5491ee074d1e9e029a46db.1700502145.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/stackdepot.c | 45 ++++++++++++++++++++++++++++-----------------
1 file changed, 28 insertions(+), 17 deletions(-)
--- a/lib/stackdepot.c~lib-stackdepot-add-depot_fetch_stack-helper
+++ a/lib/stackdepot.c
@@ -310,6 +310,7 @@ depot_alloc_stack(unsigned long *entries
stack->handle.extra = 0;
memcpy(stack->entries, entries, flex_array_size(stack, entries, size));
pool_offset += required_size;
+
/*
* Let KMSAN know the stored stack record is initialized. This shall
* prevent false positive reports if instrumented code accesses it.
@@ -319,6 +320,32 @@ depot_alloc_stack(unsigned long *entries
return stack;
}
+static struct stack_record *depot_fetch_stack(depot_stack_handle_t handle)
+{
+ union handle_parts parts = { .handle = handle };
+ /*
+ * READ_ONCE pairs with potential concurrent write in
+ * depot_alloc_stack().
+ */
+ int pool_index_cached = READ_ONCE(pool_index);
+ void *pool;
+ size_t offset = parts.offset << DEPOT_STACK_ALIGN;
+ struct stack_record *stack;
+
+ if (parts.pool_index > pool_index_cached) {
+ WARN(1, "pool index %d out of bounds (%d) for stack id %08x\n",
+ parts.pool_index, pool_index_cached, handle);
+ return NULL;
+ }
+
+ pool = stack_pools[parts.pool_index];
+ if (!pool)
+ return NULL;
+
+ stack = pool + offset;
+ return stack;
+}
+
/* Calculates the hash for a stack. */
static inline u32 hash_stack(unsigned long *entries, unsigned int size)
{
@@ -462,14 +489,6 @@ EXPORT_SYMBOL_GPL(stack_depot_save);
unsigned int stack_depot_fetch(depot_stack_handle_t handle,
unsigned long **entries)
{
- union handle_parts parts = { .handle = handle };
- /*
- * READ_ONCE pairs with potential concurrent write in
- * depot_alloc_stack.
- */
- int pool_index_cached = READ_ONCE(pool_index);
- void *pool;
- size_t offset = parts.offset << DEPOT_STACK_ALIGN;
struct stack_record *stack;
*entries = NULL;
@@ -482,15 +501,7 @@ unsigned int stack_depot_fetch(depot_sta
if (!handle || stack_depot_disabled)
return 0;
- if (parts.pool_index > pool_index_cached) {
- WARN(1, "pool index %d out of bounds (%d) for stack id %08x\n",
- parts.pool_index, pool_index_cached, handle);
- return 0;
- }
- pool = stack_pools[parts.pool_index];
- if (!pool)
- return 0;
- stack = pool + offset;
+ stack = depot_fetch_stack(handle);
*entries = stack->entries;
return stack->size;
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
lib-stackdepot-print-disabled-message-only-if-truly-disabled.patch
lib-stackdepot-check-disabled-flag-when-fetching.patch
lib-stackdepot-simplify-__stack_depot_save.patch
lib-stackdepot-drop-valid-bit-from-handles.patch
lib-stackdepot-add-depot_fetch_stack-helper.patch
lib-stackdepot-use-fixed-sized-slots-for-stack-records.patch
lib-stackdepot-fix-and-clean-up-atomic-annotations.patch
lib-stackdepot-rework-helpers-for-depot_alloc_stack.patch
lib-stackdepot-rename-next_pool_required-to-new_pool_required.patch
lib-stackdepot-store-next-pool-pointer-in-new_pool.patch
lib-stackdepot-store-free-stack-records-in-a-freelist.patch
lib-stackdepot-use-read-write-lock.patch
lib-stackdepot-use-list_head-for-stack-record-links.patch
kmsan-use-stack_depot_save-instead-of-__stack_depot_save.patch
lib-stackdepot-kasan-add-flags-to-__stack_depot_save-and-rename.patch
lib-stackdepot-add-refcount-for-records.patch
lib-stackdepot-allow-users-to-evict-stack-traces.patch
kasan-remove-atomic-accesses-to-stack-ring-entries.patch
kasan-check-object_size-in-kasan_complete_mode_report_info.patch
kasan-use-stack_depot_put-for-tag-based-modes.patch
kasan-use-stack_depot_put-for-generic-mode.patch
lib-stackdepot-adjust-depot_pools_cap-for-kmsan.patch
