Revision c39866f268f89868df17724cd2262d121552d8c9 authored by Nathan Chancellor on 28 September 2020, 22:48:54 UTC, committed by Kees Cook on 27 October 2020, 18:32:21 UTC
After turning on warnings for orphan section placement, enabling CONFIG_UNWINDER_FRAME_POINTER instead of CONFIG_UNWINDER_ARM causes thousands of warnings when clang + ld.lld are used: $ scripts/config --file arch/arm/configs/multi_v7_defconfig \ -d CONFIG_UNWINDER_ARM \ -e CONFIG_UNWINDER_FRAME_POINTER $ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 defconfig zImage ld.lld: warning: init/built-in.a(main.o):(.ARM.extab) is being placed in '.ARM.extab' ld.lld: warning: init/built-in.a(main.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(main.o):(.ARM.extab.ref.text) is being placed in '.ARM.extab.ref.text' ld.lld: warning: init/built-in.a(do_mounts.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(do_mounts.o):(.ARM.extab) is being placed in '.ARM.extab' ld.lld: warning: init/built-in.a(do_mounts_rd.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(do_mounts_rd.o):(.ARM.extab) is being placed in '.ARM.extab' ld.lld: warning: init/built-in.a(do_mounts_initrd.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(initramfs.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(initramfs.o):(.ARM.extab) is being placed in '.ARM.extab' ld.lld: warning: init/built-in.a(calibrate.o):(.ARM.extab.init.text) is being placed in '.ARM.extab.init.text' ld.lld: warning: init/built-in.a(calibrate.o):(.ARM.extab) is being placed in '.ARM.extab' These sections are handled by the ARM_UNWIND_SECTIONS define, which is only added to the list of sections when CONFIG_ARM_UNWIND is set. CONFIG_ARM_UNWIND is a hidden symbol that is only selected when CONFIG_UNWINDER_ARM is set so CONFIG_UNWINDER_FRAME_POINTER never handles these sections. According to the help text of CONFIG_UNWINDER_ARM, these sections should be discarded so that the kernel image size is not affected. Fixes: 5a17850e251a ("arm/build: Warn on orphan section placement") Link: https://github.com/ClangBuiltLinux/linux/issues/1152 Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Review-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> [kees: Made the discard slightly more specific] Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200928224854.3224862-1-natechancellor@gmail.com
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File | Mode | Size |
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auxdisplay | ||
binderfs | ||
bpf | ||
configfs | ||
connector | ||
ftrace | ||
hidraw | ||
hw_breakpoint | ||
kdb | ||
kfifo | ||
kmemleak | ||
kobject | ||
kprobes | ||
livepatch | ||
mei | ||
mic | ||
nitro_enclaves | ||
pidfd | ||
pktgen | ||
qmi | ||
rpmsg | ||
seccomp | ||
timers | ||
trace_events | ||
trace_printk | ||
uhid | ||
v4l | ||
vfio-mdev | ||
vfs | ||
watch_queue | ||
watchdog | ||
Kconfig | -rw-r--r-- | 6.7 KB |
Makefile | -rw-r--r-- | 1.3 KB |
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