This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: last_100_frees.stp on aarch64 is crashing while doing sprint_ubacktrace()
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: William Cohen <wcohen at redhat dot com>
- Cc: systemtap at sourceware dot org, Mark Wielaard <mjw at redhat dot com>, Pratyush Anand <panand at redhat dot com>, Dave Long <dave dot long at linaro dot org>
- Date: Fri, 19 Jun 2015 12:38:26 -0400
- Subject: Re: last_100_frees.stp on aarch64 is crashing while doing sprint_ubacktrace()
- Authentication-results: sourceware.org; auth=none
- References: <55843208 dot 6030003 at redhat dot com>
William Cohen <wcohen@redhat.com> writes:
> [...] Any suggestions on how to further diagnose this? Other
> nuggets of information available in the output below?
Certainly. One would start from retaining a copy of the systemtap
module, built with
# stap -p4 -k -DDEBUG_UNWIND=2 -G CONFIG_DEBUGINFO=y ...
so one can apply normal post-mortem debugging techniques to the module
(disassemble at the trapping address, deduce whether data or code is
more suspect, etc.). dwarf-dump the target process to check the dwarf
data by hand. Attempt run; collect vmcore and any panicy messages.
runtime/unwind.c:processCFI() works its way through the dwarf data
with some protection against e.g. bad data, but it may be
insufficient.
> Jun 19 10:36:46 apm-mustang-ev3-11 kernel: Hardware name: AppliedMicro Mustang/Mustang, BIOS 1.1.0 Apr 22 2015
> Jun 19 10:36:46 apm-mustang-ev3-11 kernel: task: fffffe01dda97300 ti: fffffe00bd960000 task.ti: fffffe00bd960000
> Jun 19 10:36:46 apm-mustang-ev3-11 kernel: PC is at processCFI.constprop.119+0x77c/0x8d8 [stap_30b4cb5617d66b47c47d1ba687c18f92_2825]
> Jun 19 10:36:46 apm-mustang-ev3-11 kernel: LR is at processCFI.constprop.119+0x75c/0x8d8 [stap_30b4cb5617d66b47c47d1ba687c18f92_2825]
> Jun 19 10:36:46 apm-mustang-ev3-11 kernel: pc : [<fffffdfffc4fa2e0>] lr : [<fffffdfffc4fa2c0>] pstate: 20000145
> [...]
> Jun 19 10:36:46 apm-mustang-ev3-11 kernel: [<fffffdfffc4fa2e0>] processCFI.constprop.119+0x77c/0x8d8 [stap_30b4cb5617d66b47c47d1ba687c18f92_2825]
> Jun 19 10:36:46 apm-mustang-ev3-11 kernel: [<fffffdfffc4fb3f4>] unwind_frame.constprop.115+0x44c/0xe1c [stap_30b4cb5617d66b47c47d1ba687c18f92_2825]
> [...]