From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Thu, 02 Aug 2001 01:13:14 +0000 Subject: Re: [Linux-ia64] Panic in linuxrc (2.4.7) Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Wed, 1 Aug 2001 16:15:43 -0700, David Mosberger said: David> Do you have CONFIG_PERFMON enabled? If not, try turning it David> on. We are investigating the problem. It looks to be a David> Heisenbug: the problem gets triggered depending on what the David> exact code layout is. Adding or removing a single bundle in David> the right place seems to make the difference... OK, this turns out to be due to an assembler bug: the assembler fails to put a stop bit in front of an "alloc" instruction if the "alloc" is preceded by a .align directive and the directive inserts one or more "nop" bundles. ;-( This bug was difficult to track down because it got triggered while psr.ic was cleared, which means that the IP reported in the tombstone is all wrong and there is no easy way to find out at which address the real fault occurred. Well, at least the workaround is easy: --- arch/ia64/kernel/entry.S-orig Wed Aug 1 12:48:26 2001 +++ arch/ia64/kernel/entry.S Wed Aug 1 18:05:31 2001 @@ -687,7 +687,7 @@ shladd in0=loc1,3,r17 mov in1=0 ;; - .align 32 +// .align 32 rse_clear_invalid: // cycle 0 { .mii Please try again with this patch applied. --david