------- Comment #5 from axel at freakout dot de 2007-06-10 10:05 ------- Subject: Re: gcc 4.2.0 compiled vanilla kernel 2.4.34.5 crashes when VIA C3 optimized -march=c3
According to rguenth at gcc dot gnu dot org: > > ------- Comment #4 from rguenth at gcc dot gnu dot org 2007-06-09 10:27 > ------- > We need this reduced to a managable testcase that gcc miscompiles. > Sorry - but kernel debugging in the early boot stage goes far beyond my capabilities. I tried to gather as much information as i can. The crash can be reproduced just with the kernel itself, no modules involved. I've added an archive with two dirs gcc-4.1.2 and gcc-4.2.0 - in each dir is the compiled kernel vmlinux and the boot image vmlinuz, with can be loaded by any bootloader (grub, lilo, syslinux, loadlin, ...). i also added the corresponding System.map's. The kernel were produced from identical (the same) source trees with gcc 4.1.2 and gcc 4.2.0 on the same machine. The gcc 4.1.2 compiled kernel boots until panic - no root fs - works ok. The gcc 4.2.0 kernel crashes with this output: ====================================================================== Kernel command line: BOOT_IMAGE=vmlinuz4.434 Initializing CPU#0 Detected 797.420 MHz processor. Console: colour VGA+ 80x25 Unable to handle kernel paging request at virtual address f000fec4 printing eip: c0295690 *pde = 00000000 Oops: 0002 CPU: 0 EIP: 0010:[<c0295690>] Not tainted EFLAGS: 00010017 eax: f00fec4 ebx: 00000000 ecx: 00000037 edx: 00000010 esi: 000994c1 edi: c0105000 ebp: 0008e000 esp: c0251fe4 ds: 0018 es: 0020 ss: 0018 Process swapper (pid: 0, stackpage=c0251000) Stack: 00000020 c0252290 00000010 00000216 c0252630 c0295ae0 c0100191 Call Trace: Code: 10 00 f3 a5 ea 19 00 00 90 bf f4 3f 8e d8 8e d0 3f a3 c1 8c <0>Kernel panic: Attempted to kill the idle task! In idle task - not syncing ====================================================================== This output is also in the archive dir of gcc-4.2.0/crash.txt The working kernel (produced from gcc-4.1.2) prints: ====================================================================== Calibrating delay loop... 1592.52 BogoMIPS ====================================================================== at the point where the gcc-4.2.0 produced kernel crashes with the above messages. Hope this helps. Axel -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32264