Subject: port-arm/24077: KCORE_MAGIC not set on crash dumps
To: None <gnats-bugs@gnats.NetBSD.org>
From: Richard Earnshaw <email@example.com>
Date: 01/13/2004 14:50:44
>Synopsis: KCORE_MAGIC not set on crash dumps
>Arrival-Date: Tue Jan 13 14:51:00 UTC 2004
>Originator: Richard Earnshaw
>Release: NetBSD 1.6ZG
System: NetBSD shark1.cambridge.arm.com 1.6ZG NetBSD 1.6ZG (SHARK1) #2: Sat Dec 20 14:19:49 GMT 2003 firstname.lastname@example.org:/work/rearnsha/netbsd/build/src/shark/sys/arch/shark/compile/SHARK1 shark
After a kernel crash and dropping int DDB typing sync will sometimes
produce a crash dump (sometimes it won't but that's a different issue.
However, on reboot, savecore reports that there is no dump.
It turns out (on debugging savecore) that the problem is that code
in libkvm detects that the dump does not have the correct KCORE_MAGIC
value and so believes that there is no dump. Even savecore -f
will not work.
break into ddb, force a crash dump and reboot. System will
report that there is no dump file.
The kernel should write out a header on the crash dump as all other
architectures do. The header should also describe the physical memory
blocks of the crashing kernel.