On Tue, Jan 02, 2007 at 05:06:14PM -0500, D. Hazelton wrote: > On Tuesday 02 January 2007 16:56, Alistair John Strachan wrote: > > On Tuesday 02 January 2007 21:10, Adrian Bunk wrote: > > [snip] > > > > > > > Comparing your report and [1], it seems that if these are the same > > > > > problem, it's not a hardware bug but a gcc or kernel bug. > > > > > > > > This bug specifically indicates some kind of miscompilation in a > > > > driver, causing boot time hangs. My problem is quite different, and > > > > more subtle. The crash happens in the same place every time, which does > > > > suggest determinism (even with various options toggled on and off, and > > > > a 300K smaller kernel image), but it takes 8-12 hours to manifest and > > > > only happens with GCC 4.1.1. ... > > > > > > Sorry if my point goes a bit away from your problem: > > > > > > My point is that we have several reported problems only visible > > > with gcc 4.1. > > > > > > Other bug reports are e.g. [2] and [3], but they are only present with > > > using gcc 4.1 _and_ using -Os. > > > > I find [2] most compelling, and I can confirm that I do have the same > > problem with or without optimisation for size. I don't use selinux nor has > > it ever been enabled. > > > > At any rate, I have absolute confirmation that it is GCC 4.1.1, because > > with GCC 3.4.6 the same kernel I reported booting three days ago is still > > cheerfully working. I regularly get uptimes of 60+ days on that machine, > > rebooting only for kernel upgrades. 2.6.19 seems to be no worse in this > > regard. > > > > Perhaps fortunately, the configs I've tried have consistently failed to > > shake the crash, so I have a semi-reproducible test case here on C3-2 > > hardware if somebody wants to investigate the problem (though it still > > takes 6-12 hours). > > The GCC code generator appears to have been rewritten between 3.4.6 and > 4.1.1.... > > I took a look at the dump he posted and there are some minor and some massive > differences between the code. In one case some of the code is swapped, in > another there is code in the 3.4.6 version that isn't in the 4.1.1... Finally > the 4.1.1 version of the function has what appears to be function calls and > these don't appear in the code generated by 3.4.6
Differences are expected since we disable unit-at-a-time for gcc < 4 and gcc development didn't stall between 3.4 and 4.1. > In other words - the code generation for 4.1.1 appears to be broken when it > comes to generating system code. Bug number for an either already open or created by you bug in the gcc Bugzilla for what you claim to be a bug in gcc? > DRH cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/