Created attachment 45816 [details] reproducer Reporting this for ada as reproducer is part of gprbuild (gprinstall) code. In some cases (return from exception handler) stack pointer is set to weird value and either stack smashing protection or storage error occurs. it's easy and 100% reproducible in Fedora linux distribution https://bugzilla.redhat.com/show_bug.cgi?id=1677173 gcc-9.0.1-0.4.fc30.armv7hl gprbuild-2018-12.fc30.armv7hl All other architectures (x86, s390x, ppc64le and aarch64 work fine) We were able to strip reproducer to ~200 LOC (attached) # gprbuild -v -cargs:Ada -O2 -g # valgrind ./exe/process ==29563== Memcheck, a memory error detector ==29563== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==29563== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info ==29563== Command: ./exe/process ==29563== warning: file does not exist '/tmp/a/satrace.log' ==29563== Warning: client switching stacks? SP change: 0xbdef07c0 --> 0x68818 ==29563== to suppress, use: --max-stackframe=1108836440 or greater aaa ==29563== Invalid write of size 4 ==29563== at 0x40C04: system__secondary_stack__ss_release (in /tmp/test/exe/process) ==29563== Address 0x68754 is 12 bytes inside data symbol "ada_main__sec_default_sized_stacks" ==29563== ==29563== Invalid read of size 4 ==29563== at 0x1A09C: _ada_process (process.adb:119) ==29563== Address 0x687ec is 164 bytes inside data symbol "ada_main__sec_default_sized_stacks" ==29563== ==29563== Invalid read of size 4 ==29563== at 0x1A0A4: _ada_process (process.adb:119) ==29563== Address 0xe1a02026 is not stack'd, malloc'd or (recently) free'd
I've reproduced manually using the reproducer and a bootstrapped gcc at r268766 gcc r265397 does not reproduce the problem. Hence I'm marking this as a regression. Between these two versions bootstrap with the configure line below fails. ../gcc-source/configure --enable-bootstrap --enable-languages=c,c++,fortran,objc,obj-c++,ada,lto --prefix=${HOME}/gcc-install --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl --enable-gnu-indirect-function --disable-sjlj-exceptions --with-tune=generic-armv7-a --with-arch=armv7-a --with-float=hard --with-fpu=vfpv3-d16 --with-abi=aapcs-linux --build=armv7hl-redhat-linux-gnueabi (mostly taken from the configure shown in `gcc -v` from the given package version)
So is this an Ada unwind bug? What kind of unwinder does Ada use?
Does this happen at -O1 too? If not, can you try and disable strict aliasing or scheduling (or other -O2 optimizations) and see what happens?
GCC 9.1 has been released.
GCC 9.2 has been released.