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    SubjectRe: [PATCH] more sanity checks in Dwarf2 unwinder
    >>  	while (unwind(info) == 0 && UNW_PC(info)) {
    >> n++;
    >> oad->ops->address(oad->data, UNW_PC(info));
    >> if (arch_unw_user_mode(info))
    >> break;
    >> + if ((sp & ~(PAGE_SIZE - 1)) == (UNW_SP(info) & ~(PAGE_SIZE - 1))
    >> + && sp > UNW_SP(info))
    >> + break;
    >Hmm, but that wouldn't catch the case when the SP is completely
    >corrupted for some reason.
    >Maybe it would be better to just run a brute force check here like
    >the old in_exception_stack(). Similar on x86-64.

    Correct. Even though I know Linus disagrees here, I'm not sure
    I want to do this, as my ultimate goal would be to eliminate the
    hand-crafted linking (which we know got broken a few times on
    x86-64, because it's so easy to forget about).
    Not the least of the reasons for this is that this increases the
    chances of stucks.

    >> + if (UNW_PC(frame) % state.codeAlign
    >> + || UNW_SP(frame) % sleb128abs(state.dataAlign)
    >> + || (pc == UNW_PC(frame) && sp == UNW_SP(frame)))
    >> + return -EIO;
    >Would it be possible to add printks for the EIOs? We want to know
    >when dwarf2 is corrupted.

    Certainly, will be a follow-up patch.

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      Last update: 2006-11-29 15:01    [W:0.021 / U:9.144 seconds]
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