https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90399
Bug ID: 90399
Summary: split-stack + shared library + static object
construction (C++)
Product: gcc
Version: 8.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libgcc
Assignee: unassigned at gcc dot gnu.org
Reporter: mkarsten at uwaterloo dot ca
Target Milestone: ---
Created attachment 46316
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46316&action=edit
example code and gdb output
I am building a shared library that internally uses split-stack and calls
__splitstack_makecontext() during construction of a static object. At runtime,
there seem to be two copies of split-stack code/variables (from libgcc.a) in
play - one that is added to the shared libray and another one that is added to
the executable. When the program is started, the following seems to happen:
- shared library copy of '__morestack_load_mmap()' initializes its copy of
'static_pagesize'
- however, the first call to '__splitstack_makecontext()' ends up in the other
instance where 'static_pagesize' is not initialized, thus 0, thus the
allocation fails and the program terminates with:
unable to allocate additional stack space: errno 22
Interestingly, gdb disassembly claims that the correct version of
__splitstack_makecontext() should be called. The stack backtrace shows that the
(executable) version
#3 0x0000555555556379 in __splitstack_makecontext ()
is called, despite the disassembly output claiming that the (shared library)
version would be called:
0x00007ffff7fc71f5 <+107>: callq 0x7ffff7fc7040
<__splitstack_makecontext@plt>
I am attaching a small example with Makefile and gdb output from triggering the
error. The bug can only be reproduced with multiple files, so I am attaching a
tgz archive. The same code works fine when avoiding the shared library (see
'make works' target in Makefile).
I have seen this with various versions of gcc on various Linux platforms
(Ubuntu and Arch). My most recent testing is with the packaged gcc 8.3.0 on
Arch Linux:
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gConfigured with: /build/gcc/src/gcc/configure
--prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
--enable-cet=autocc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
--enable-cet=auto
Thread model: posix
gcc version 8.3.0 (GCC)
Please let me know, if you need further information.
