[Buildroot] [Bug 10586] New: musl gcc has ifunc enabled when musl doesn't support it

[Buildroot] [Bug 10586] New: musl gcc has ifunc enabled when musl doesn't support it

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=10586

            Bug ID: 10586
           Summary: musl gcc has ifunc enabled when musl doesn't support
                    it
           Product: buildroot
           Version: unspecified
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P5
         Component: Other
          Assignee: unassigned at buildroot.uclibc.org
          Reporter: nathan.renniewaldock at gmail.com
                CC: buildroot at uclibc.org
  Target Milestone: ---

musl doesn't support ifunc[1], so needs to be specifically disabled as it
defaults to enabled.

Test case[2]:

$ cat >a.c <<EOD
int main(){ return 0; }
EOD

$ gcc -o a a.c -latomic

$ ./a
Error relocating /lib/libatomic.so.1: __atomic_store_8: symbol not found
Error relocating /lib/libatomic.so.1: __atomic_exchange_8: symbol not found
Error relocating /lib/libatomic.so.1: __atomic_load_8: symbol not found
Error relocating /lib/libatomic.so.1: __atomic_compare_exchange_8: symbol not
found


[1] http://www.openwall.com/lists/musl/2014/11/11/2
[2] http://www.openwall.com/lists/musl/2015/11/17/9

(tested buildroot 2017.11)

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[Buildroot] [Bug 10586] musl gcc has ifunc enabled when musl doesn't support it

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=10586

Carlos Santos <unixmania@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at buildroot.uclibc |unixmania at gmail.com
                   |.org                        |
             Status|NEW                         |ASSIGNED

--- Comment #1 from Carlos Santos <unixmania@gmail.com> ---
Sorry for the late answer. I'm taking this bug.

I can't reproduce this on a system buit with the following defconfig:

BR2_x86_64=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD=y
BR2_TOOLCHAIN_EXTERNAL_URL="https://toolchains.bootlin.com/downloads/releases/toolchains/x86-64-core-i7/tarballs/x86-64-core-i7--musl--bleeding-edge-2018.11-1.tar.bz2"
BR2_TOOLCHAIN_EXTERNAL_GCC_8=y
BR2_TOOLCHAIN_EXTERNAL_HEADERS_4_14=y
BR2_TOOLCHAIN_EXTERNAL_CUSTOM_MUSL=y
BR2_TOOLCHAIN_EXTERNAL_CXX=y
BR2_TOOLCHAIN_EXTERNAL_GDB_SERVER_COPY=y
BR2_SYSTEM_DHCP="eth0"
BR2_LINUX_KERNEL=y
BR2_LINUX_KERNEL_CUSTOM_VERSION=y
BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.16"
BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/x86_64/linux.config"
BR2_TARGET_ROOTFS_EXT2=y
# BR2_TARGET_ROOTFS_TAR is not set

$ echo 'int main(){ return 0; }' > /tmp/a.c
$ host/bin/x86_64-linux-gcc -o target/root/a /tmp/a.c -latomic
$ host/bin/x86_64-linux-readelf -d target/root/a

Dynamic section at offset 0x2eb0 contains 16 entries:
  Tag        Type                         Name/Value
 0x0000000000000001 (NEEDED)             Shared library: [libatomic.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so]
 0x000000000000000c (INIT)               0x401000
 0x000000000000000d (FINI)               0x401175
 0x0000000000000004 (HASH)               0x400290
 0x000000006ffffef5 (GNU_HASH)           0x4002b8
 0x0000000000000005 (STRTAB)             0x400340
 0x0000000000000006 (SYMTAB)             0x4002e0
 0x000000000000000a (STRSZ)              54 (bytes)
 0x000000000000000b (SYMENT)             24 (bytes)
 0x0000000000000015 (DEBUG)              0x0
 0x0000000000000003 (PLTGOT)             0x404000
 0x0000000000000002 (PLTRELSZ)           24 (bytes)
 0x0000000000000014 (PLTREL)             RELA
 0x0000000000000017 (JMPREL)             0x400378
 0x0000000000000000 (NULL)               0x0

$ make
$ qemu-kvm -M pc -m 1024 -kernel "images/bzImage" \
  -drive file=images/rootfs.ext2,if=virtio,format=raw \
  -append "root=/dev/vda console=ttyS0,115200n8 net.ifnames=0" \
  -net nic,model=virtio -net "user${hostfwd}" -nographic -enable-kvm \
  -rtc base=utc -device virtio-rng-pci -watchdog i6300esb
[...]
Welcome to Buildroot
buildroot login: root
# ./a
# 

Can you still see the error?

Could you please post a defconfig on which the problem happens?

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[Buildroot] [Bug 10586] musl gcc has ifunc enabled when musl doesn't support it

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=10586

--- Comment #2 from Carlos Santos <unixmania@gmail.com> ---
Patch submitted: https://patchwork.ozlabs.org/patch/1145462/

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[Buildroot] [Bug 10586] musl gcc has ifunc enabled when musl doesn't support it

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=10586

--- Comment #3 from Carlos Santos <unixmania@gmail.com> ---
(In reply to Carlos Santos from comment #2)

Please disregard it. That patch is for bug 10806.

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[Buildroot] [Bug 10586] musl gcc has ifunc enabled when musl doesn't support it

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=10586

Carlos Santos <unixmania@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |NEEDINFO

--- Comment #4 from Carlos Santos <unixmania@gmail.com> ---
Closing, since it could not be reproduced and the submitter did not provide
additional information. Feel free to reopen if newer evidences raise.

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