One process traces another.
When the traced process tries to read, write or execute an unmapped
address it is stopped with a SIGSEGV signal.
The tracer now wants to determine the traced process' faulted address.
According to the (2.2.19) kernel source
.../arch/i386/mm/fault.c:do_page_fault()
such a fault in user mode causes the offending address and error code to
be saved in
tsk->tss.cr2
and
tsk->tss.error_code
respectively. There do not appear to be ptrace() or /proc hooks
to extract this data directly. In earlier unices extraction of this
data would have required grubbing around in /dev/kmem using the
kernel namelist as a guide.
How should a tracer extract this information under a current
(2.2.*, 2.4.*) Linux?
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This archive was generated by hypermail 2b29 : Sun Sep 30 2001 - 21:01:12 EST