path: root/drivers
diff options
authorArnd Bergmann <arnd@arndb.de>2017-03-28 11:57:27 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-04-08 17:56:02 +0200
commit7064dc7fc13b2994d33ae540ffb7a3a05ac463bf (patch)
tree6d189ae4027ed27345cb548ec58ea4ab8474da1a /drivers
parente22aa9d781a27a961581c57442911309fb86a48e (diff)
lkdtm: turn off kcov for lkdtm_rodata_do_nothing:
I ran into a link error on ARM64 for lkdtm_rodata_do_nothing: drivers/misc/built-in.o: In function `lkdtm_rodata_do_nothing': :(.rodata+0x68c8): relocation truncated to fit: R_AARCH64_CALL26 against symbol `__sanitizer_cov_trace_pc' defined in .text section in kernel/built-in.o I did not analyze this further, but my theory is that we would need a trampoline to call __sanitizer_cov_trace_pc(), but the linker (correctly) only adds trampolines for callers in executable sections. Disabling KCOV for this one file avoids the build failure with no other practical downsides I can think of. The problem can only happen on kernels that contain both kcov and lkdtm, so if we want to backport this, it should be in the earliest version that has both (v4.8). Fixes: 5c9a8750a640 ("kernel: add kcov code coverage") Fixes: 9a49a528dcf3 ("lkdtm: add function for testing .rodata section") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 4c4d6dc03181..4fb10af2ea1c 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -61,6 +61,8 @@ lkdtm-$(CONFIG_LKDTM) += lkdtm_perms.o
lkdtm-$(CONFIG_LKDTM) += lkdtm_rodata_objcopy.o
lkdtm-$(CONFIG_LKDTM) += lkdtm_usercopy.o
+KCOV_INSTRUMENT_lkdtm_rodata.o := n
OBJCOPYFLAGS_lkdtm_rodata_objcopy.o := \
--set-section-flags .text=alloc,readonly \

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