[PATCH v2 02/14] stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth

Kees Cook
2025-05-23T04:39:38Z

The Clang stack depth tracking implementation has a fixed name for
the stack depth tracking callback, "__sanitizer_cov_stack_depth", so
rename the GCC plugin function to match since the plugin has no external
dependencies on naming.

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <linux-hardening@vger.kernel.org>
---
security/Kconfig.hardening | 4 +-
scripts/gcc-plugins/stackleak_plugin.c | 52 +++++++++++++-------------
include/linux/kstack_erase.h | 2 +-
kernel/kstack_erase.c | 4 +-
tools/objtool/check.c | 2 +-
5 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index 125b35e2ef0f..f7aa2024ab25 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -129,8 +129,8 @@ config KSTACK_ERASE_TRACK_MIN_SIZE
help
The KSTACK_ERASE option instruments the kernel code for tracking
the lowest border of the kernel stack (and for some other purposes).
- It inserts the stackleak_track_stack() call for the functions with
- a stack frame size greater than or equal to this parameter.
+ It inserts the __sanitizer_cov_stack_depth() call for the functions
+ with a stack frame size greater than or equal to this parameter.
If unsure, leave the default value 100.

config KSTACK_ERASE_METRICS
diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c
index d20c47d21ad8..e486488c867d 100644
--- a/scripts/gcc-plugins/stackleak_plugin.c
+++ b/scripts/gcc-plugins/stackleak_plugin.c
@@ -9,7 +9,7 @@
* any of the gcc libraries
*
* This gcc plugin is needed for tracking the lowest border of the kernel stack.
- * It instruments the kernel code inserting stackleak_track_stack() calls:
+ * It instruments the kernel code inserting __sanitizer_cov_stack_depth() calls:
* - after alloca();
* - for the functions with a stack frame size greater than or equal
* to the "track-min-size" plugin parameter.
@@ -33,7 +33,7 @@ __visible int plugin_is_GPL_compatible;

static int track_frame_size = -1;
static bool build_for_x86 = false;
-static const char track_function[] = "stackleak_track_stack";
+static const char track_function[] = "__sanitizer_cov_stack_depth";
static bool disable = false;
static bool verbose = false;

@@ -58,7 +58,7 @@ static void add_stack_tracking_gcall(gimple_stmt_iterator *gsi, bool after)
cgraph_node_ptr node;
basic_block bb;

- /* Insert calling stackleak_track_stack() */
+ /* Insert calling __sanitizer_cov_stack_depth() */
stmt = gimple_build_call(track_function_decl, 0);
gimple_call = as_a_gcall(stmt);
if (after)
@@ -120,12 +120,12 @@ static void add_stack_tracking_gasm(gimple_stmt_iterator *gsi, bool after)
gcc_assert(build_for_x86);

/*
- * Insert calling stackleak_track_stack() in asm:
- * asm volatile("call stackleak_track_stack"
+ * Insert calling __sanitizer_cov_stack_depth() in asm:
+ * asm volatile("call __sanitizer_cov_stack_depth"
* :: "r" (current_stack_pointer))
* Use ASM_CALL_CONSTRAINT trick from arch/x86/include/asm/asm.h.
* This constraint is taken into account during gcc shrink-wrapping
- * optimization. It is needed to be sure that stackleak_track_stack()
+ * optimization. It is needed to be sure that __sanitizer_cov_stack_depth()
* call is inserted after the prologue of the containing function,
* when the stack frame is prepared.
*/
@@ -137,7 +137,7 @@ static void add_stack_tracking_gasm(gimple_stmt_iterator *gsi, bool after)
input = build_tree_list(NULL_TREE, build_const_char_string(2, "r"));
input = chainon(NULL_TREE, build_tree_list(input, sp_decl));
vec_safe_push(inputs, input);
- asm_call = gimple_build_asm_vec("call stackleak_track_stack",
+ asm_call = gimple_build_asm_vec("call __sanitizer_cov_stack_depth",
inputs, NULL, NULL, NULL);
gimple_asm_set_volatile(asm_call, true);
if (after)
@@ -151,11 +151,11 @@ static void add_stack_tracking(gimple_stmt_iterator *gsi, bool after)
{
/*
* The 'no_caller_saved_registers' attribute is used for
- * stackleak_track_stack(). If the compiler supports this attribute for
- * the target arch, we can add calling stackleak_track_stack() in asm.
+ * __sanitizer_cov_stack_depth(). If the compiler supports this attribute for
+ * the target arch, we can add calling __sanitizer_cov_stack_depth() in asm.
* That improves performance: we avoid useless operations with the
* caller-saved registers in the functions from which we will remove
- * stackleak_track_stack() call during the stackleak_cleanup pass.
+ * __sanitizer_cov_stack_depth() call during the stackleak_cleanup pass.
*/
if (lookup_attribute_spec(get_identifier("no_caller_saved_registers")))
add_stack_tracking_gasm(gsi, after);
@@ -165,7 +165,7 @@ static void add_stack_tracking(gimple_stmt_iterator *gsi, bool after)

/*
* Work with the GIMPLE representation of the code. Insert the
- * stackleak_track_stack() call after alloca() and into the beginning
+ * __sanitizer_cov_stack_depth() call after alloca() and into the beginning
* of the function if it is not instrumented.
*/
static unsigned int stackleak_instrument_execute(void)
@@ -205,7 +205,7 @@ static unsigned int stackleak_instrument_execute(void)
DECL_NAME_POINTER(current_function_decl));
}

- /* Insert stackleak_track_stack() call after alloca() */
+ /* Insert __sanitizer_cov_stack_depth() call after alloca() */
add_stack_tracking(&gsi, true);
if (bb == entry_bb)
prologue_instrumented = true;
@@ -241,7 +241,7 @@ static unsigned int stackleak_instrument_execute(void)
return 0;
}

- /* Insert stackleak_track_stack() call at the function beginning */
+ /* Insert __sanitizer_cov_stack_depth() call at the function beginning */
bb = entry_bb;
if (!single_pred_p(bb)) {
/* gcc_assert(bb_loop_depth(bb) ||
@@ -270,15 +270,15 @@ static void remove_stack_tracking_gcall(void)
rtx_insn *insn, *next;

/*
- * Find stackleak_track_stack() calls. Loop through the chain of insns,
+ * Find __sanitizer_cov_stack_depth() calls. Loop through the chain of insns,
* which is an RTL representation of the code for a function.
*
* The example of a matching insn:
- * (call_insn 8 4 10 2 (call (mem (symbol_ref ("stackleak_track_stack")
- * [flags 0x41] <function_decl 0x7f7cd3302a80 stackleak_track_stack>)
- * [0 stackleak_track_stack S1 A8]) (0)) 675 {*call} (expr_list
- * (symbol_ref ("stackleak_track_stack") [flags 0x41] <function_decl
- * 0x7f7cd3302a80 stackleak_track_stack>) (expr_list (0) (nil))) (nil))
+ * (call_insn 8 4 10 2 (call (mem (symbol_ref ("__sanitizer_cov_stack_depth")
+ * [flags 0x41] <function_decl 0x7f7cd3302a80 __sanitizer_cov_stack_depth>)
+ * [0 __sanitizer_cov_stack_depth S1 A8]) (0)) 675 {*call} (expr_list
+ * (symbol_ref ("__sanitizer_cov_stack_depth") [flags 0x41] <function_decl
+ * 0x7f7cd3302a80 __sanitizer_cov_stack_depth>) (expr_list (0) (nil))) (nil))
*/
for (insn = get_insns(); insn; insn = next) {
rtx body;
@@ -318,7 +318,7 @@ static void remove_stack_tracking_gcall(void)
if (SYMBOL_REF_DECL(body) != track_function_decl)
continue;

- /* Delete the stackleak_track_stack() call */
+ /* Delete the __sanitizer_cov_stack_depth() call */
delete_insn_and_edges(insn);
#if BUILDING_GCC_VERSION < 8000
if (GET_CODE(next) == NOTE &&
@@ -340,12 +340,12 @@ static bool remove_stack_tracking_gasm(void)
gcc_assert(build_for_x86);

/*
- * Find stackleak_track_stack() asm calls. Loop through the chain of
+ * Find __sanitizer_cov_stack_depth() asm calls. Loop through the chain of
* insns, which is an RTL representation of the code for a function.
*
* The example of a matching insn:
* (insn 11 5 12 2 (parallel [ (asm_operands/v
- * ("call stackleak_track_stack") ("") 0
+ * ("call __sanitizer_cov_stack_depth") ("") 0
* [ (reg/v:DI 7 sp [ current_stack_pointer ]) ]
* [ (asm_input:DI ("r")) ] [])
* (clobber (reg:CC 17 flags)) ]) -1 (nil))
@@ -375,7 +375,7 @@ static bool remove_stack_tracking_gasm(void)
continue;

if (strcmp(ASM_OPERANDS_TEMPLATE(body),
- "call stackleak_track_stack")) {
+ "call __sanitizer_cov_stack_depth")) {
continue;
}

@@ -389,7 +389,7 @@ static bool remove_stack_tracking_gasm(void)

/*
* Work with the RTL representation of the code.
- * Remove the unneeded stackleak_track_stack() calls from the functions
+ * Remove the unneeded __sanitizer_cov_stack_depth() calls from the functions
* which don't call alloca() and don't have a large enough stack frame size.
*/
static unsigned int stackleak_cleanup_execute(void)
@@ -474,13 +474,13 @@ static bool stackleak_gate(void)
return track_frame_size >= 0;
}

-/* Build the function declaration for stackleak_track_stack() */
+/* Build the function declaration for __sanitizer_cov_stack_depth() */
static void stackleak_start_unit(void *gcc_data __unused,
void *user_data __unused)
{
tree fntype;

- /* void stackleak_track_stack(void) */
+ /* void __sanitizer_cov_stack_depth(void) */
fntype = build_function_type_list(void_type_node, NULL_TREE);
track_function_decl = build_fn_decl(track_function, fntype);
DECL_ASSEMBLER_NAME(track_function_decl); /* for LTO */
diff --git a/include/linux/kstack_erase.h b/include/linux/kstack_erase.h
index 4e432eefa4d0..bf3bf1905557 100644
--- a/include/linux/kstack_erase.h
+++ b/include/linux/kstack_erase.h
@@ -80,7 +80,7 @@ static inline void stackleak_task_init(struct task_struct *t)
asmlinkage void noinstr stackleak_erase(void);
asmlinkage void noinstr stackleak_erase_on_task_stack(void);
asmlinkage void noinstr stackleak_erase_off_task_stack(void);
-void __no_caller_saved_registers noinstr stackleak_track_stack(void);
+void __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void);

#else /* !CONFIG_KSTACK_ERASE */
static inline void stackleak_task_init(struct task_struct *t) { }
diff --git a/kernel/kstack_erase.c b/kernel/kstack_erase.c
index 201b846f8345..e49bb88b4f0a 100644
--- a/kernel/kstack_erase.c
+++ b/kernel/kstack_erase.c
@@ -156,7 +156,7 @@ asmlinkage void noinstr stackleak_erase_off_task_stack(void)
__stackleak_erase(false);
}

-void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
+void __used __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void)
{
unsigned long sp = current_stack_pointer;

@@ -174,4 +174,4 @@ void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
current->lowest_stack = sp;
}
}
-EXPORT_SYMBOL(stackleak_track_stack);
+EXPORT_SYMBOL(__sanitizer_cov_stack_depth);
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 31088a138bc9..dad81194a81b 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1192,7 +1192,7 @@ static const char *uaccess_safe_builtin[] = {
"__ubsan_handle_shift_out_of_bounds",
"__ubsan_handle_load_invalid_value",
/* KSTACK_ERASE */
- "stackleak_track_stack",
+ "__sanitizer_cov_stack_depth",
/* TRACE_BRANCH_PROFILING */
"ftrace_likely_update",
/* STACKPROTECTOR */
--
2.34.1