linux-kernel - [tip: locking/core] stackdepot: Enable context analysis

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <176762845530.510.12382375981998234833.tip-bot2@tip-bot2>
Date: Mon, 05 Jan 2026 15:54:15 -0000
From: "tip-bot2 for Marco Elver" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Marco Elver <elver@...gle.com>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: locking/core] stackdepot: Enable context analysis

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     c3d3023f1cf3de10f2d2f83b0d011fa7cab16cf0
Gitweb:        https://git.kernel.org/tip/c3d3023f1cf3de10f2d2f83b0d011fa7cab16cf0
Author:        Marco Elver <elver@...gle.com>
AuthorDate:    Fri, 19 Dec 2025 16:40:20 +01:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Mon, 05 Jan 2026 16:43:35 +01:00

stackdepot: Enable context analysis

Enable context analysis for stackdepot.

Signed-off-by: Marco Elver <elver@...gle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://patch.msgid.link/20251219154418.3592607-32-elver@google.com
---
 lib/Makefile     |  1 +
 lib/stackdepot.c | 20 ++++++++++++++------
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index 89defef..e755eee 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -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
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index de0b002..166f50a 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -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;