kstack_erase: Support Clang stack depth tracking

Wire up CONFIG_KSTACK_ERASE to Clang 21's new stack depth tracking
callback[1] option.

Link: https://clang.llvm.org/docs/SanitizerCoverage.html#tracing-stack-depth [1]
Acked-by: Nicolas Schier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>
This commit is contained in:
Kees Cook committed 2025-07-26 14:28:35 -07:00
1 parent 6676fd3c99
commit a8f0b1f8ef
2 files changed
+10 -1

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+6
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@@ -8,6 +8,12 @@ kstack-erase-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE) += -fplugin-arg-stack
DISABLE_KSTACK_ERASE := -fplugin-arg-stackleak_plugin-disable
endif
ifdef CONFIG_CC_IS_CLANG
kstack-erase-cflags-y += -fsanitize-coverage=stack-depth
kstack-erase-cflags-y += -fsanitize-coverage-stack-depth-callback-min=$(CONFIG_KSTACK_ERASE_TRACK_MIN_SIZE)
DISABLE_KSTACK_ERASE := -fno-sanitize-coverage=stack-depth
endif
KSTACK_ERASE_CFLAGS := $(kstack-erase-cflags-y)
export STACKLEAK_CFLAGS DISABLE_KSTACK_ERASE
+4 -1
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@@ -82,10 +82,13 @@ choice
endchoice
config CC_HAS_SANCOV_STACK_DEPTH_CALLBACK
def_bool $(cc-option,-fsanitize-coverage-stack-depth-callback-min=1)
config KSTACK_ERASE
bool "Poison kernel stack before returning from syscalls"
depends on HAVE_ARCH_KSTACK_ERASE
depends on GCC_PLUGINS
depends on GCC_PLUGINS || CC_HAS_SANCOV_STACK_DEPTH_CALLBACK
help
This option makes the kernel erase the kernel stack before
returning from system calls. This has the effect of leaving