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    SubjectRe: [patch 15/21] ptrace changes
    Martin Schwidefsky wrote:
    > On Mon, 2008-11-03 at 11:14 -0600, David Smith wrote:
    >> Is this correct, or should the 1st syscall argument be found in
    >> regs->orig_gpr2 by syscall_get_arguments()/syscall_set_arguments()?
    > The question is when do syscall_get_arguments and syscall_set_arguments
    > functions get called? If they are called on a call chain that started
    > from do_syscall_trace_enter then we'd have to use orig_gpr2 instead of
    > gprs[2] but if the functions are not called via do_syscall_trace_enter
    > the first argument is located in grprs[2]. As far as I can see the sole
    > user of syscall_get_arguments is collect_syscall which is used to get
    > the registers of a blocked process. In this case the kernel call chain
    > does not include do_syscall_trace_enter, therefore the first argument is
    > in gprs[2], no?

    But, collect_syscall() also calls syscall_get_nr():

    *callno = syscall_get_nr(target, regs);
    if (*callno != -1L && maxargs > 0)
    syscall_get_arguments(target, regs, 0, maxargs, args);

    Both syscall_get_nr() *and* syscall_get_arguments() returning gprs[2]
    can't be right, can it?

    David Smith
    Red Hat
    256.217.0141 (direct)
    256.837.0057 (fax)

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      Last update: 2008-11-06 19:27    [W:0.020 / U:15.256 seconds]
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