Re: [Qemu-ppc] [Qemu-devel] Bugs when cross-compiling qemu for Windows with mingw 8.1, executable doesn't run

[Stefan Weil]

Am 17.08.2018 um 09:32 schrieb David Hildenbrand:
> On 18.07.2018 08:33, Howard Spoelstra wrote:
>> Hi all,
>>
>> I have two issues when cross compiling current master for Windows with
>> mingw 8.1. Host is Fedora29. See further below for gcc and mingw
>> versions.
>>
>> Reproduce with:
>> ./configure --cross-prefix=x86_64-w64-mingw32-
>> --target-list="ppc-softmmu" --enable-gtk --with-gtkabi=3.0
>> --enable-sdl --with-sdlabi=2.0
>>
>> Issue 1: Two bugs show up during compilation related to strncpy.
>> Replacing the offenders with memcpy seems to fix this.
>>
>> First time:
>> block/sheepdog.c: In function 'find_vdi_name':
>> block/sheepdog.c:1239:5: error: 'strncpy' specified bound 256 equals
>> destination size [-Werror=stringop-truncation]
>>      strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN);
>>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> Second time:
>> migration/global_state.c: In function 'global_state_store_running':
>> migration/global_state.c:45:5: error: 'strncpy' specified bound 100
>> equals destination size [-Werror=stringop-truncation]
>>      strncpy((char *)global_state.runstate,
>>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>             state, sizeof(global_state.runstate));
>>             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
> 
> These two reports should be independent of general functionality
> (sheepdog, migration). So what you see is most likely unrelated to this.
> 
>> Issue 2: once strncpy has been replaced with memcpy in these two
>> instances, I can successfully compile, but the executable doesn't run
>> in Windows.
>> I tried to debug, and this is what gdb told me:
>>
>> (gdb) run
>> Starting program: c:\qemu-fedora29beta\qemu-system-ppc-debug.exe -L
>> c:\qemu-fedora29beta\pc-bios -boot c -m 256 -M "mac99,via=pmu"
>> -prom-env "boot-args=-v" -prom-env "auto-boot?=true" -prom-env
>> "vga-ndrv?=true" -hda c:\Mac-disks\9.2.qcow2 -netdev
>> "user,id=network01" -device "sungem,netdev=network01" -sdl -d int
>> [New Thread 948.0x6d8]
>> [New Thread 948.0x2778]
>> [New Thread 948.0x286c]
>> [New Thread 948.0x3d0]
>>
>> Program received signal SIGSEGV, Segmentation fault.
>> getpagesize () at util/oslib-win32.c:535
>> 535     util/oslib-win32.c: No such file or directory.
> 
> This warning is just from GDB, not able to locate you sources I guess.
> 
>> (gdb) bt full
>> #0  getpagesize () at util/oslib-win32.c:535
> 
> Wonder why we should get a SEGFAULT in that simple function. As
> discussed offline, the functionality in general seems to work (if this
> function is compiled and run independently in your environment).
> 
> But maybe this backtrace is just misleading.
> 
>>         system_info = {{dwOemId = 56491488, {wProcessorArchitecture =
>> 64992, wReserved = 861}}, dwPageSize = 0,
>>           lpMinimumApplicationAddress = 0x99cca4
>> <register_module_init+60>, lpMaximumApplicationAddress = 0x3,
>>           dwActiveProcessorMask = 11102192, dwNumberOfProcessors =
>> 56584576, dwProcessorType = 0,
>>           dwAllocationGranularity = 200, wProcessorLevel = 0,
>> wProcessorRevision = 0}
> 
> dwPageSize = 0, I assume this is some random data on the stack and
> GetSystemInfo never got executed. I wonder where this segfault comes from.
> 
>> #1  0x00000000009b7fcd in init_real_host_page_size () at util/pagesize.c:16
>> No locals.
>> #2  0x00000000009bc5f2 in __do_global_ctors ()
>> No symbol table info available.
>> #3  0x00000000004013ca in __tmainCRTStartup () at ../crt/crtexe.c:324
>>         lock_free = <optimized out>
>>         fiberid = <optimized out>
>>         nested = <optimized out>
>>         lpszCommandLine = <optimized out>
>>         StartupInfo = {cb = 104, lpReserved = 0x3778e00 "", lpDesktop
>> = 0x377f440 "Winsta0\\Default",
>>           lpTitle = 0x3786280
>> "c:\\qemu-fedora29beta\\qemu-system-ppc-debug.exe", dwX = 0, dwY = 0,
>> dwXSize = 0,
>>           dwYSize = 0, dwXCountChars = 0, dwYCountChars = 0,
>> dwFillAttribute = 0, dwFlags = 0, wShowWindow = 0,
>>           cbReserved2 = 0, lpReserved2 = 0x0, hStdInput =
>> 0xffffffffffffffff, hStdOutput = 0xffffffffffffffff,
>>           hStdError = 0xffffffffffffffff}
>>         inDoubleQuote = <optimized out>
>> #4  0x00000000004014fb in WinMainCRTStartup () at ../crt/crtexe.c:184
>>         ret = 255
>> (gdb)
>>
>>
>> Gcc and mingw versions used:
>>
>> address@hidden qemu-master]$ gcc -v
>> Using built-in specs.
>> COLLECT_GCC=gcc
>> COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/8/lto-wrapper
>> OFFLOAD_TARGET_NAMES=nvptx-none
>> OFFLOAD_TARGET_DEFAULT=1
>> Target: x86_64-redhat-linux
>> Configured with: ../configure --enable-bootstrap
>> --enable-languages=c,c++,fortran,objc,obj-c++,ada,go,lto --prefix=/usr
>> --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-libmpx --enable-offload-targets=nvptx-none
>> --without-cuda-driver --enable-gnu-indirect-function --enable-cet
>> --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux
>> Thread model: posix
>> gcc version 8.1.1 20180626 (Red Hat 8.1.1-4) (GCC)
>>
>> address@hidden qemu-master]$ x86_64-w64-mingw32-gcc -v
>> Using built-in specs.
>> COLLECT_GCC=x86_64-w64-mingw32-gcc
>> COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-w64-mingw32/8.1.0/lto-wrapper
>> Target: x86_64-w64-mingw32
>> Configured with: ../configure --prefix=/usr --bindir=/usr/bin
>> --includedir=/usr/include --mandir=/usr/share/man
>> --infodir=/usr/share/info --datadir=/usr/share
>> --build=x86_64-redhat-linux-gnu --host=x86_64-redhat-linux-gnu
>> --with-gnu-as --with-gnu-ld --verbose --without-newlib
>> --disable-multilib --disable-plugin --with-system-zlib --disable-nls
>> --without-included-gettext --disable-win32-registry
>> --enable-languages=c,c++,objc,obj-c++,fortran
>> --with-bugurl=http://bugzilla.redhat.com/bugzilla --with-cloog
>> --enable-threads=posix --enable-libgomp --target=x86_64-w64-mingw32
>> --with-sysroot=/usr/x86_64-w64-mingw32/sys-root
>> --with-gxx-include-dir=/usr/x86_64-w64-mingw32/sys-root/mingw/include/c++
>> Thread model: posix
>> gcc version 8.1.0 20180502 (Fedora MinGW 8.1.0-1.fc29) (GCC)
>>
>> Thanks for looking into this,
>>
>> Best,
>> Howard
>>
> 
> No being a win32/mingw expert, Stefan any idea?


I'd try a debug build (configure [...] --enable-debug).

My installers (https://qemu.weilnetz.de/w64/) were built with
x86_64-w64-mingw32-gcc (GCC) 6.3.0 20170516 (from Debian Stretch).
Howard, perhaps you can try whether they show the same runtime SIGSEGV.
When I run your command line with a dummy disk image, OpenBIOS boots fine.

Kind regards,
Stefan