Hello. I think the reason for all that complexity is
because there is
no guarantee that a very stale core image won't be erased
from the swap
partition during subsequent runs after the actual crash. In
other words,
it is an attempt to implement the policy that a savecore is
only written
to /var/crash the first time a machine reboots after a panic
and crash
dump. Just opening the swap partition, looking for a core
header, and
writing to /var/crash pretty much guarantees you'll be
writing a /var/crash
image every time a machine reboots.
One way to work around this problem, perhaps, without
implementing the
complexity you're trying to deal with, is to introduce a
swap scrubber into
the boot sequence. The idea here is that the core header
could be erased
from the dump partition after savecore is run, but before
swapping is
enabled. This mechanism is probably not full proof, because
it doesn't
account for machines which don't make it to multiuser mode
between reboots,
but it probably does cover 90% of the installations.
-Brian
On Dec 10, 12:05pm, "Devon H. O'Dell" wrote:
} Subject: Savecore Complexity Questions
} Hey guys,
}
} After getting the initial minidump, I started working on
modifying
} savecore / libkvm to store it to disk. I'm kind of at a
point where I
} feel like this isn't the right solution and am questioning
savecore's
} current complexity. For instance, it seems like it will
refuse to save a
} core if the kernel that cored does not match the currently
running
} kernel, and it relies on libkvm for reading the core
header, the core
} itself, and writing it to the disk.
}
} This seems to be needlessly complex. I don't understand
why savecore
} shouldn't just open the configured dump partition, poke
around for the
} core magic, and just write what it finds to disk. (So this
is what I'm
} planning on implementing and have actually begun work
on).
}
} Does anybody have other / better suggestions about this
(or information
} on why savecore has all this -- what seems to me to be
needless --
} complexity)?
}
} Thanks,
}
} --dho
>-- End of excerpt from "Devon H. O'Dell"
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