Commit c3d3023f authored by Marco Elver's avatar Marco Elver Committed by Peter Zijlstra
Browse files

stackdepot: Enable context analysis 



Enable context analysis for stackdepot.

Signed-off-by: default avatarMarco Elver <elver@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-32-elver@google.com
parent 0eaa911f

lib/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -250,6 +250,7 @@ obj-$(CONFIG_POLYNOMIAL) += polynomial.o 
# Prevent the compiler from calling builtins like memcmp() or bcmp() from this

# file.

CFLAGS_stackdepot.o += -fno-builtin

CONTEXT_ANALYSIS_stackdepot.o := y

obj-$(CONFIG_STACKDEPOT) += stackdepot.o

KASAN_SANITIZE_stackdepot.o := n

# In particular, instrumenting stackdepot.c with KMSAN will result in infinite

lib/stackdepot.c

+14 −6
Original line number Diff line number Diff line
@@ -61,18 +61,18 @@ static unsigned int stack_bucket_number_order; 
/* Hash mask for indexing the table. */

static unsigned int stack_hash_mask;



/* The lock must be held when performing pool or freelist modifications. */

static DEFINE_RAW_SPINLOCK(pool_lock);

/* Array of memory regions that store stack records. */

static void **stack_pools;

static void **stack_pools __pt_guarded_by(&pool_lock);

/* Newly allocated pool that is not yet added to stack_pools. */

static void *new_pool;

/* Number of pools in stack_pools. */

static int pools_num;

/* Offset to the unused space in the currently used pool. */

static size_t pool_offset = DEPOT_POOL_SIZE;

static size_t pool_offset __guarded_by(&pool_lock) = DEPOT_POOL_SIZE;

/* Freelist of stack records within stack_pools. */

static LIST_HEAD(free_stacks);

/* The lock must be held when performing pool or freelist modifications. */

static DEFINE_RAW_SPINLOCK(pool_lock);

static __guarded_by(&pool_lock) LIST_HEAD(free_stacks);



/* Statistics counters for debugfs. */

enum depot_counter_id {
@@ -291,6 +291,7 @@ EXPORT_SYMBOL_GPL(stack_depot_init); 
 * Initializes new stack pool, and updates the list of pools.

 */

static bool depot_init_pool(void **prealloc)

	__must_hold(&pool_lock)

{

	lockdep_assert_held(&pool_lock);
@@ -338,6 +339,7 @@ static bool depot_init_pool(void **prealloc) 


/* Keeps the preallocated memory to be used for a new stack depot pool. */

static void depot_keep_new_pool(void **prealloc)

	__must_hold(&pool_lock)

{

	lockdep_assert_held(&pool_lock);
@@ -357,6 +359,7 @@ static void depot_keep_new_pool(void **prealloc) 
 * the current pre-allocation.

 */

static struct stack_record *depot_pop_free_pool(void **prealloc, size_t size)

	__must_hold(&pool_lock)

{

	struct stack_record *stack;

	void *current_pool;
@@ -391,6 +394,7 @@ static struct stack_record *depot_pop_free_pool(void **prealloc, size_t size) 


/* Try to find next free usable entry from the freelist. */

static struct stack_record *depot_pop_free(void)

	__must_hold(&pool_lock)

{

	struct stack_record *stack;
@@ -428,6 +432,7 @@ static inline size_t depot_stack_record_size(struct stack_record *s, unsigned in 
/* Allocates a new stack in a stack depot pool. */

static struct stack_record *

depot_alloc_stack(unsigned long *entries, unsigned int nr_entries, u32 hash, depot_flags_t flags, void **prealloc)

	__must_hold(&pool_lock)

{

	struct stack_record *stack = NULL;

	size_t record_size;
@@ -486,6 +491,7 @@ depot_alloc_stack(unsigned long *entries, unsigned int nr_entries, u32 hash, dep 
}



static struct stack_record *depot_fetch_stack(depot_stack_handle_t handle)

	__must_not_hold(&pool_lock)

{

	const int pools_num_cached = READ_ONCE(pools_num);

	union handle_parts parts = { .handle = handle };
@@ -502,7 +508,8 @@ static struct stack_record *depot_fetch_stack(depot_stack_handle_t handle) 
		return NULL;

	}



	pool = stack_pools[pool_index];

	/* @pool_index either valid, or user passed in corrupted value. */

	pool = context_unsafe(stack_pools[pool_index]);

	if (WARN_ON(!pool))

		return NULL;
@@ -515,6 +522,7 @@ static struct stack_record *depot_fetch_stack(depot_stack_handle_t handle) 


/* Links stack into the freelist. */

static void depot_free_stack(struct stack_record *stack)

	__must_not_hold(&pool_lock)

{

	unsigned long flags;