After inspecting a strange case in the mips64 kernel with address
errors, I'm starting to think there's a problem in the do_ade()
implementation. I think the 32-bit kernel may have a similar problem,
but I haven't really inspected it. The issue is where the kernel's
emulation of an address error causes another address error (NOT a page
fault).
Basically, I don't see how the exception table stuff in
emulate_load_store_insn is going to work. Consider this scenario:
- user process does a 'sw' (for example) to an illegal address
above xuseg but below xsseg
- do_ade calls emulate_load_store_insn, which tries swl/swr
- the swl again hits an illegal address, this time in the
kernel's context
- do_ade does NOT check the exception table for the swl
- emulate_load_store_insn goes to the 'swl' part of the switch
- die_if_kernel DOES __die before the SIGBUS is delivered.
So I don't see how the ex_table stuff is useful at all. Shouldn't
do_ade() do the exception table grovelling before calling
emulate_load_store_insn?
Kip
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