From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELtjiiylLxVXcLTBL+Dz9XXHfSmhoAGKMDdFizu0YPxg7485daX1+O6tVjoRDJQJ5tGOlBmU ARC-Seal: i=1; a=rsa-sha256; t=1521483813; cv=none; d=google.com; s=arc-20160816; b=VH3EPuU3HSB4a1mFCiPvdaHgY3eA9wnHZ9w4CnyhA+ppOwXzpgUiA06uXI3F4dqXER Rx3jKzw3oU5/Im+F2LZ0KjnWcKk3fTTjMCPoZesPBABM0jxlweiJaLh8uWnVTouX/7i8 4tDgbUA/rB6v/P5WHhop1qMHjWF5+ibkVXEf4nXPaTWnH/4cAIeUhztd8RzbqNUwJBcl 2A9dm8zNVodAD1+8+tgBBtwNSnon6oBcVtCnHW1KeyDTYSBPW0wl9pds9Z7Tzp2tncEA AvuQw8niWTF2zmRQXODkhqbYROZSGzJ/nq8zB0O/pz61FNKgro5b8edBJBTZ9cq81lUA aUwQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=wF+9772r45PQfWP3M3F+HGdntpVPlvJ4+TSywRn/lgk=; b=yONhdY3S0oKWhbY6VPC0zhS4X54rJz3sgLv11dkLih3E6MdsjaJjV+LD9nxmP9eeXG qr2zTarua2DUnopWWQI+bl49CXEpI2O0fRtgBrqgO49nkmV7OhkCpMvt+XrcHGVjuQEb 4b51kM3QKgT5qF/kb42SnsXXTS/aoAwgV3E21FePLtNTP5zP8Er6WgYiGhlcxZZB56ob j8KTJQDDadi6qqjEsnebxKwwZuoeH4ts5iPEnL3uvNqJ9/Qin1MQDEw5B9MhMR6II8PD nCCTNO9jYk9yr+6KQK8l7HwNOjIfRH5wuVRJJtFPdRbPtcZnrtrFH3OPyKBWCVgsWon9 TTNg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Dmitry Vyukov , Kees Cook , Sasha Levin Subject: [PATCH 4.9 126/241] lkdtm: turn off kcov for lkdtm_rodata_do_nothing: Date: Mon, 19 Mar 2018 19:06:31 +0100 Message-Id: <20180319180756.416129214@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180319180751.172155436@linuxfoundation.org> References: <20180319180751.172155436@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1595391411037569790?= X-GMAIL-MSGID: =?utf-8?q?1595391411037569790?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann [ Upstream commit 7064dc7fc13b2994d33ae540ffb7a3a05ac463bf ] 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 Acked-by: Dmitry Vyukov Acked-by: Kees Cook Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/misc/Makefile | 2 ++ 1 file changed, 2 insertions(+) --- 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 := OBJCOPYFLAGS_lkdtm_rodata_objcopy.o := \ --set-section-flags .text=alloc,readonly \