https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114115
Bug ID: 114115
Summary: xz-utils segfaults when built with -fprofile-generate
(bad interaction between IFUNC and binding?)
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: gcov-profile
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
Target Milestone: ---
This was first reported downstream in Gentoo at https://bugs.gentoo.org/925415.
xz-utils-5.6.0 (it started to use IFUNC recently for crc32) started to
segfault, but only when built with -march=x86-64-v3 & -fprofile-generate.
For convenience, a broken builddir is available at
http://dev.gentoo.org/~sam/bugs/xz/pgo/xz-5.6.0-abi_x86_64.amd64.tar.xz.
```
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x00000000000041b6 in ?? ()
(gdb) bt
#0 0x00000000000041b6 in ?? ()
#1 0x00007f861b2fcc75 in crc32_resolve () at
/var/tmp/portage/app-arch/xz-utils-5.6.0/work/xz-5.6.0/src/liblzma/check/crc32_fast.c:140
#2 0x00007f861b3541e4 in elf_machine_rela (map=<optimized out>,
scope=<optimized out>, reloc=0x7f861b2e05c8, sym=0x7f861b2ddfd8,
version=<optimized out>,
reloc_addr_arg=0x7f861b32ab10 <lzma_crc32@got[plt]>, skip_ifunc=<optimized
out>) at ../sysdeps/x86_64/dl-machine.h:314
#3 elf_dynamic_do_Rela (map=0x7f861b343160, scope=<optimized out>,
reladdr=<optimized out>, relsize=<optimized out>, nrelative=<optimized out>,
lazy=<optimized out>,
skip_ifunc=<optimized out>) at
/var/tmp/portage/sys-libs/glibc-2.39-r1/work/glibc-2.39/elf/do-rel.h:147
#4 _dl_relocate_object (l=l@entry=0x7f861b343160, scope=<optimized out>,
reloc_mode=<optimized out>, consider_profiling=<optimized out>,
consider_profiling@entry=0) at dl-reloc.c:301
#5 0x00007f861b363d61 in dl_main (phdr=<optimized out>, phnum=<optimized out>,
user_entry=<optimized out>, auxv=<optimized out>) at rtld.c:2311
#6 0x00007f861b36059f in _dl_sysdep_start
(start_argptr=start_argptr@entry=0x7ffdeae5bd20,
dl_main=dl_main@entry=0x7f861b362060 <dl_main>)
at ../sysdeps/unix/sysv/linux/dl-sysdep.c:140
#7 0x00007f861b361da2 in _dl_start_final (arg=0x7ffdeae5bd20) at rtld.c:494
#8 _dl_start (arg=0x7ffdeae5bd20) at rtld.c:581
#9 0x00007f861b360b88 in _start () from /lib64/ld-linux-x86-64.so.2
#10 0x0000000000000006 in ?? ()
#11 0x00007ffdeae5cfc9 in ?? ()
#12 0x00007ffdeae5d021 in ?? ()
#13 0x00007ffdeae5d026 in ?? ()
#14 0x00007ffdeae5d034 in ?? ()
#15 0x00007ffdeae5d03a in ?? ()
#16 0x00007ffdeae5d04b in ?? ()
#17 0x0000000000000000 in ?? ()
(gdb)
```
```
(gdb) frame 1
#1 0x00007f861b2fcc75 in crc32_resolve () at
/var/tmp/portage/app-arch/xz-utils-5.6.0/work/xz-5.6.0/src/liblzma/check/crc32_fast.c:140
140 {
(gdb) list
135 // This resolver is shared between all three dispatch methods. It
serves as
136 // the ifunc resolver if ifunc is supported, otherwise it is called as
a
137 // regular function by the constructor or first call resolution
methods.
138 static crc32_func_type
139 crc32_resolve(void)
140 {
141 return is_arch_extension_supported()
142 ? &crc32_arch_optimized : &crc32_generic;
143 }
144
(gdb)
```
