[Libunwind-devel] unwind within a signal handler (in linux / arm)

[Harald Servat]

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Dear all,

  I've just downloaded a GIT clone of the libunwind and installed it in
a linux/ARM machine.

  We use libunwind from an library that monitors an application. This
library uses periodical sampling to collect some information (including
the callstack). I've found that libunwind segfaults when is issued from
the signal handler. I'm attaching the gdb output below.

  Has anyone seen this issue before?

Thank you in advance.

warning: Breakpoint address adjusted from 0x4002eb25 to 0x4002eb24.
Core was generated by `./mpi_ping'.
Program terminated with signal 11, Segmentation fault.
#0  dwarf_get (cursor=0xbe9edbf8) at ../include/tdep-arm/libunwind_i.h:114
114       *val = *(unw_word_t *) DWARF_GET_LOC (loc);
(gdb) where
#0  dwarf_get (cursor=0xbe9edbf8) at ../include/tdep-arm/libunwind_i.h:114
#1  _ULarm_step (cursor=0xbe9edbf8) at arm/Gstep.c:228
#2  0x4017e8c2 in trace_callers (time=<value optimized out>, offset=6,
type=1) at calltrace.c:78
#3  0x4017ebe6 in Extrae_SamplingHandler (address=0xbe9f1d50) at
sampling.c:83
#4  0x4017ec68 in TimeSamplingHandler (sig=<value optimized out>,
siginfo=0x0, context=<value optimized out>) at sampling.c:151
#5  <signal handler called>
#6  0x42112e9a in MPIDI_CH3I_Progress () from /usr/lib/libmpich.so.3
#7  0x42160038 in MPID_nem_network_poll () from /usr/lib/libmpich.so.3
#8  0x42160038 in MPID_nem_network_poll () from /usr/lib/libmpich.so.3
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
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