Jivko Sabev wrote: > I have performed the tests Jari requested and here are the results: Thanks. > The base case the started this whole thread: > > gcc --version > gcc (GCC) 4.1.2 (Ubuntu 4.1.2-0ubuntu4) In this case, that (32bit x86 ubuntu-7.04) gcc compiles valid source code to invalid object code. > dietlibc version: 0.3 (from an ubuntu deb binary package) dietlibc works as expected. No issues with it. I tested that initrd-BAD.gz that you sent me (compiled using 32bit x86 ubuntu gcc-4.1.2) in my test box. It failed to boot on my test box, same as your box. initrd-OK.gz that I compiled myself on my test box worked ok. More testing/debugging follows: Trying to manually run /linuxrc program from working initrd: # zcat /boot/initrd-OK.gz >/tmp/foo # mount -t minix /tmp/foo /mnt -o loop # /mnt/linuxrc ERROR: initrd config says USEPIVOT=1, but bootloader acts like USEPIVOT=0 # umount /mnt Above error message is what I expected. /linuxrc code detected that it was not running as process number 1, and terminated with an error message. The pid needs to be 1 because later that code execve()s init process which must run as pid 1. Now trying to manually run /linuxrc program from your failing initrd: # zcat /boot/initrd-BAD.gz >/tmp/foo # mount -t minix /tmp/foo /mnt -o loop # /mnt/linuxrc Segmentation fault # gdb /mnt/linuxrc [snip] (gdb) run Starting program: /mnt/linuxrc warning: shared library handler failed to enable breakpoint Program received signal SIGSEGV, Segmentation fault. 0x08048383 in ?? () (gdb) disas 0x08048370 0x080483a3 Dump of assembler code from 0x8048370 to 0x80483a3: 0x8048370: lea 0x4(%esp,1),%ecx 0x8048374: and $0xfffffff0,%esp 0x8048377: pushl 0xfffffffc(%ecx) 0x804837a: push %ebp 0x804837b: mov %esp,%ebp 0x804837d: sub $0x5a8,%esp 0x8048383: mov %gs:0x14,%edx <==== Seg fault here 0x804838a: mov %edx,0xfffffff0(%ebp) 0x804838d: xor %edx,%edx 0x804838f: mov %ecx,0xfffffff4(%ebp) 0x8048392: mov %ebx,0xfffffff8(%ebp) 0x8048395: mov %esi,0xfffffffc(%ebp) 0x8048398: mov 0x4(%ecx),%eax 0x804839b: mov %eax,0x8049be8 0x80483a0: call 0x8048798 End of assembler dump. (gdb) quit A debugging session is active. Do you still want to close the debugger?(y or n) y # umount /mnt gcc compiler put that bogus "0x8048383: mov %gs:0x14,%edx" instruction there. Instruction "0x804838d: xor %edx,%edx" is first "x=0;" assignment of main() function. I am going to add GCC= configuration entry to build-initrd.sh. The default will be "gcc", same as before. I will also add a note that the default gcc compiler on 32 bit x86 ubuntu 7.04 needs it overridden to "gcc-3.3". A patch is included. -- Jari Ruusu 1024R/3A220F51 5B 4B F9 BB D3 3F 52 E9 DB 1D EB E3 24 0E A9 DD --- ../loop-AES-v3.2a/build-initrd.sh 2007-05-14 15:18:12.000000000 +0300 +++ build-initrd.sh 2007-08-14 21:08:27.000000000 +0300 @@ -2,7 +2,7 @@ # # build-initrd.sh # -# Written by Jari Ruusu, May 14 2007 +# Written by Jari Ruusu, August 14 2007 # # Copyright 2001-2007 by Jari Ruusu. # Redistribution of this file is permitted under the GNU Public License. @@ -192,6 +192,11 @@ # The dietlibc can be found at http://www.fefe.de/dietlibc/ USEDIETLIBC=1 +# C compiler used to compile /linuxrc program. +# 32bit x86 ubuntu-7.04 gcc-4.1.2 is known to miscompile /linuxrc. Affected +# users should install gcc-3.3 package, and change this to GCC=gcc-3.3 +GCC=gcc + # 1 = load extra module, 0 = don't load # If this is enabled, module must be manually copied to # /boot/modules-KERNELRELEASE/ directory under name like foomatic.o @@ -632,9 +637,9 @@ EOF if [ ${USEDIETLIBC} == 1 ] ; then - diet gcc -Wall -O2 -s -static -pipe tmp-c-$$.c -o tmp-c-$$ + diet ${GCC} -Wall -O2 -s -static -pipe tmp-c-$$.c -o tmp-c-$$ else - gcc -Wall -O2 -s -static -nostartfiles -pipe tmp-c-$$.c -o tmp-c-$$ + ${GCC} -Wall -O2 -s -static -nostartfiles -pipe tmp-c-$$.c -o tmp-c-$$ fi rm -f tmp-c-$$.[co] - Linux-crypto: cryptography in and on the Linux system Archive: http://mail.nl.linux.org/linux-crypto/
