6baec880d7
Building an arm64 allmodconfig kernel with clang results in over 140 warnings about overly large stack frames, the worst ones being: drivers/gpu/drm/panel/panel-sitronix-st7789v.c:196:12: error: stack frame size of 20224 bytes in function 'st7789v_prepare' drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td028ttec1.c:196:12: error: stack frame size of 13120 bytes in function 'td028ttec1_panel_enable' drivers/usb/host/max3421-hcd.c:1395:1: error: stack frame size of 10048 bytes in function 'max3421_spi_thread' drivers/net/wan/slic_ds26522.c:209:12: error: stack frame size of 9664 bytes in function 'slic_ds26522_probe' drivers/crypto/ccp/ccp-ops.c:2434:5: error: stack frame size of 8832 bytes in function 'ccp_run_cmd' drivers/media/dvb-frontends/stv0367.c:1005:12: error: stack frame size of 7840 bytes in function 'stv0367ter_algo' None of these happen with gcc today, and almost all of these are the result of a single known issue in llvm. Hopefully it will eventually get fixed with the clang-9 release. In the meantime, the best idea I have is to turn off asan-stack for clang-8 and earlier, so we can produce a kernel that is safe to run. I have posted three patches that address the frame overflow warnings that are not addressed by turning off asan-stack, so in combination with this change, we get much closer to a clean allmodconfig build, which in turn is necessary to do meaningful build regression testing. It is still possible to turn on the CONFIG_ASAN_STACK option on all versions of clang, and it's always enabled for gcc, but when CONFIG_COMPILE_TEST is set, the option remains invisible, so allmodconfig and randconfig builds (which are normally done with a forced CONFIG_COMPILE_TEST) will still result in a mostly clean build. Link: http://lkml.kernel.org/r/20190222222950.3997333-1-arnd@arndb.de Link: https://bugs.llvm.org/show_bug.cgi?id=38809 Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Qian Cai <cai@lca.pw> Reviewed-by: Mark Brown <broonie@kernel.org> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
57 lines
1.6 KiB
Makefile
57 lines
1.6 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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ifdef CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_INLINE
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call_threshold := 10000
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else
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call_threshold := 0
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endif
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KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
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CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
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cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
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# -fasan-shadow-offset fails without -fsanitize
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CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
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-fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
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$(call cc-option, -fsanitize=kernel-address \
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-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
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ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
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CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
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else
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# Now add all the compiler specific options that are valid standalone
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CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
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$(call cc-param,asan-globals=1) \
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$(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
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$(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \
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$(call cc-param,asan-use-after-scope=1) \
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$(call cc-param,asan-instrument-allocas=1)
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endif
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ifdef CONFIG_KASAN_EXTRA
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CFLAGS_KASAN += $(call cc-option, -fsanitize-address-use-after-scope)
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endif
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endif # CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_SW_TAGS
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ifdef CONFIG_KASAN_INLINE
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instrumentation_flags := -mllvm -hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
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else
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instrumentation_flags := -mllvm -hwasan-instrument-with-calls=1
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endif
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CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
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-mllvm -hwasan-instrument-stack=0 \
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$(instrumentation_flags)
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endif # CONFIG_KASAN_SW_TAGS
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ifdef CONFIG_KASAN
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CFLAGS_KASAN_NOSANITIZE := -fno-builtin
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endif
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