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    SubjectRe: [PATCH 12/X] uprobes: x86: introduce abort_xol()
    On 10/21, Srikar Dronamraju wrote:
    >
    > > If it is not clear, abort_xol() is needed when we should
    > > re-execute the original insn (replaced with int3), see the
    > > next patch.
    >
    > We should be removing the breakpoint in abort_xol().

    Why? See also below.

    > Otherwise if we just set the instruction pointer to int3 and signal a
    > sigill, then the user may be confused why a breakpoint is generating
    > SIGILL.

    Which user?

    gdb? Of course it can be confused. But it can be confused in any case.

    > > +void abort_xol(struct pt_regs *regs)
    > > +{
    > > + // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    > > + // !!! Dear Srikar and Ananth, please implement me !!!
    > > + // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    > > + struct uprobe_task *utask = current->utask;
    > > + regs->ip = utask->vaddr;
    >
    > nit:
    > Shouldnt we be setting the ip to the next instruction after this
    > instruction?

    Not sure...

    We should restart the same insn. Say, if the probed insn
    was "*(int*)0 = 0", it should be executed again after SIGSEGV. Unless
    the task was killed by this signal.

    And in this case we should call uprobe_consumer()->handler() again,
    we shouldn't remove "int3".

    > I have applied all your patches and ran tests, the tests are all
    > passing.
    >
    > I will fold them into my patches and send them out.

    Great, thanks.

    Oleg.



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