- For 2.6.14 and later ia64 kdumps, taken either as a result of the
INIT switch, or when an MCA exception has occurred, several problems
needed to be addressed. First, the "pseudo-task" that handles the
kdump operation due to an INIT or MCA was not being recognized as
the "panic" task. Secondly, the backtraces of the per-cpu INIT
or MCA handling pseudo-tasks only went back as far as their entry
onto their own per-cpu stacks, and did not show the backtrace of
the task that was running on that cpu when the INIT or MCA event
occurred. This version recognizes the pseudo-task that handles the
kdump operation; and for each cpu, the active tasks' backtraces now
also show a transition back to the task that was running on that cpu
when the INIT or MCA event occurred. (j-nomura@xxxxxxxxxxxxx)
- To address the need to display per-cpu variables, the "p"
command has been modified to recognize "per_cpu__xxx" arguments
when the kernel is SMP, in order to prevent the attempt to display
the contents of a variable whose symbol value does not represent
the actual location of its data. In that case, the data type of
the per-cpu variable will be displayed, followed by the addresses
of each per-cpu instance. Given that information, a proper command
can be utilized in order to display the data. For example, to look
at the per-cpu buffer_head accounting for cpu 2:
crash> p per_cpu__bh_accounting
PER-CPU DATA TYPE:
struct bh_accounting per_cpu__bh_accounting;
PER-CPU ADDRESSES:
[0]: c5405a80
[1]: c540da80
[2]: c5415a80
[3]: c541da80
crash> bh_accounting c5415a80
struct bh_accounting {
nr = 434,
ratelimit = 2216
}
Note that "p" on the first command line above is optional, because
whenever a data variable is entered alone, crash will recognize it
as such, and pass it to the "p" command by default. I had thought
of putting this functionality into the "struct" command, but many
of the per-cpu variables are pointers, arrays, etc.. So for the
non-structure cases, the "rd" command would be more appropriate,
or alternatively a cobbled-together gdb print command.
(anderson@xxxxxxxxxx)
- A consolidated cleanup and minor fixes patch has been applied
to
the experimental x86_64 dwarf CFI unwind facility.
(rachita@xxxxxxxxxx)
- Also related to the experimental x86_64 dwarf CFI unwind facility,
fixed a problem where if a "set unwind on" was done, and
followed
by a subsequent "set unwind off", then the "bt" output could
either
cause a segmentation violation, or display backtrace data
that was
different from the original. (anderson@xxxxxxxxxx)
Download from: http://people.redhat.com/anderson
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