The patch titled
Subject: kasan: use stack_depot_put for tag-based modes
has been added to the -mm mm-unstable branch. Its filename is
kasan-use-stack_depot_put-for-tag-based-modes.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kasan-use-stack_depot_put-for-tag-based-modes.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: kasan: use stack_depot_put for tag-based modes
Date: Wed, 13 Sep 2023 19:14:44 +0200
Make tag-based KASAN modes to evict stack traces from the stack depot once
they are evicted from the stack ring.
Internally, pass STACK_DEPOT_FLAG_GET to stack_depot_save_flags (via
kasan_save_stack) to increment the refcount when saving a new entry to
stack ring and call stack_depot_put when removing an entry from stack
ring.
Link: https://lkml.kernel.org/r/6e2367e7693aa107f05c649abe06180fff847bb4.1694625260.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
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>
---
mm/kasan/report_tags.c | 1 +
mm/kasan/tags.c | 10 ++++++++--
2 files changed, 9 insertions(+), 2 deletions(-)
--- a/mm/kasan/report_tags.c~kasan-use-stack_depot_put-for-tag-based-modes
+++ a/mm/kasan/report_tags.c
@@ -7,6 +7,7 @@
#include <linux/atomic.h>
#include "kasan.h"
+#include "../slab.h"
extern struct kasan_stack_ring stack_ring;
--- a/mm/kasan/tags.c~kasan-use-stack_depot_put-for-tag-based-modes
+++ a/mm/kasan/tags.c
@@ -97,12 +97,13 @@ static void save_stack_info(struct kmem_
gfp_t gfp_flags, bool is_free)
{
unsigned long flags;
- depot_stack_handle_t stack;
+ depot_stack_handle_t stack, old_stack;
u64 pos;
struct kasan_stack_ring_entry *entry;
void *old_ptr;
- stack = kasan_save_stack(gfp_flags, STACK_DEPOT_FLAG_CAN_ALLOC);
+ stack = kasan_save_stack(gfp_flags,
+ STACK_DEPOT_FLAG_CAN_ALLOC | STACK_DEPOT_FLAG_GET);
/*
* Prevent save_stack_info() from modifying stack ring
@@ -121,6 +122,8 @@ next:
if (!try_cmpxchg(&entry->ptr, &old_ptr, STACK_RING_BUSY_PTR))
goto next; /* Busy slot. */
+ old_stack = entry->stack;
+
entry->size = cache->object_size;
entry->pid = current->pid;
entry->stack = stack;
@@ -129,6 +132,9 @@ next:
entry->ptr = object;
read_unlock_irqrestore(&stack_ring.lock, flags);
+
+ if (old_stack)
+ stack_depot_put(old_stack);
}
void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
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
