[uml-devel] UML/64bit is miscompiled by gcc 4.0.3 on Ubuntu 6.06 LTS

[Blaisorblade <blaisorblade@yahoo.it>]

I've found now the time to run a test, and I found that while on Ubuntu, until 
now, I couldn't compile a 64bit UML (I thought of some regression I didn't 
have the time to debug), compiling the same code with gcc 3.4 gets a fully 
working UML.

The used UML is release 2.6.18.6.

Ubuntu's gcc is:

$ gcc -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured 
with: ../src/configure -v --enable-languages=c,c++,java,f95,objc,ada,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --program-suffix=-4.0 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug --enable-java-awt=gtk-default --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.4.2-gcj-4.0-1.4.2.0/jre --enable-mpfr --disable-werror --enable-checking=release 
x86_64-linux-gnu
Thread model: posix
gcc version 4.0.3 (Ubuntu 4.0.3-1ubuntu5)


Without any errors, after these messages:

kjournald starting.  Commit interval 5 seconds
EXT3-fs: mounted filesystem with ordered data mode.
VFS: Mounted root (ext3 filesystem) readonly.

it hangs giving the following result at strace -p (I've printed two 
consecutive iterations of the same messages to show that they are the same):

--- SIGCHLD (Child exited) @ 0 (0) ---
wait4(31586, [{WIFSTOPPED(s) && WSTOPSIG(s) == SIGSEGV}], WSTOPPED, NULL) = 
31586
ptrace(PTRACE_GETREGS, 31586, 0, 0x6096dac8) = 0
ptrace(PTRACE_GETFPREGS, 31586, 0, 0x6096dba0) = 0
ptrace(PTRACE_CONT, 31586, 0, SIGSEGV)  = 0
--- SIGCHLD (Child exited) @ 0 (0) ---
wait4(31586, [{WIFSTOPPED(s) && WSTOPSIG(s) == SIGUSR1}], WSTOPPED, NULL) = 
31586
ptrace(PTRACE_SETREGS, 31586, 0, 0x6096dac8) = 0
ptrace(PTRACE_SETFPREGS, 31586, 0, 0x6096dba0) = 0
ptrace(PTRACE_SYSCALL, 31586, 0, SIG_0) = 0

--- SIGCHLD (Child exited) @ 0 (0) ---
wait4(31586, [{WIFSTOPPED(s) && WSTOPSIG(s) == SIGSEGV}], WSTOPPED, NULL) = 
31586
ptrace(PTRACE_GETREGS, 31586, 0, 0x6096dac8) = 0
ptrace(PTRACE_GETFPREGS, 31586, 0, 0x6096dba0) = 0
ptrace(PTRACE_CONT, 31586, 0, SIGSEGV)  = 0
--- SIGCHLD (Child exited) @ 0 (0) ---
wait4(31586, [{WIFSTOPPED(s) && WSTOPSIG(s) == SIGUSR1}], WSTOPPED, NULL) = 
31586
ptrace(PTRACE_SETREGS, 31586, 0, 0x6096dac8) = 0
ptrace(PTRACE_SETFPREGS, 31586, 0, 0x6096dba0) = 0
ptrace(PTRACE_SYSCALL, 31586, 0, SIG_0) = 0

I'll have to verify whether some code in the stubs is miscompiled. But not 
until... well, I dunno when I'll be back...

Anybody else with the same problem?
-- 
Inform me of my mistakes, so I can add them to my list!
Paolo Giarrusso, aka Blaisorblade
http://www.user-mode-linux.org/~blaisorblade
Chiacchiera con i tuoi amici in tempo reale! 
 http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com 


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