Re: 4GB+DEBUG_PAGEALLOC oopses with 2.6.0-test3-mm1
From: Manfred Spraul
Date: Mon Aug 11 2003 - 10:27:17 EST
Ingo Molnar wrote:
(in theory it's possible that kernel-internal mounts pass in a pointer
where pointer + PAGE_SIZE is not a valid kernel address - if this happens
then we'd get a hard crash.)
Exactly that happens.
I'm running with CONFIG_PAGE_DEBUG, i.e. unallocated pages are marked as
non-present in the linear mapping.
Regarding the i386 trap handler: show_registers tries to hexdump the
current instructions. It did a __get_user, to avoid causing a fault when
%eip is invalid.
Now it contains:
if ((user_mode(regs) && get_user(c, eip)) ||
(!user_mode(regs) && __direct_get_user(c, eip))) {
printk(" Bad EIP value.");
break;
}
I.e. it's already fixed.
--
Manfred
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