Paul Pluzhnikov <[email protected]>
writes:
>> Does anyone have any ideas?
>
> Run your program under gdb. When GDB stops with the intentional
> SIGSEGV or SIGABRT, do "sig SIGSEGV" or "sig SIGABRT", which should
> continue the program into the sigal handler, into obtain_backtrace
> and into libunwind, and then GDB should stop with another crash. At
> that point you'll know where this is crashing, and perhaps why. Use
> the usual debugging techniques if the reason for the crash is not
> obvious.
Thanks for the tip. Doing this, the program immediately
SIGSEGV/SIGABRTs in __errno_location.
(gdb) run
Starting program: /tmp/backtrace
warning: Unable to find libthread_db matching inferior's thread
library, thread debugging will not be available.
warning: the debug information found in "/lib/libc-2.12.1.so.debug"
does not match "/lib/libc.so.6" (CRC mismatch).
warning: Unable to find libthread_db matching inferior's thread
library, thread debugging will not be available.
I'm a bit confused about those messages. I'm sure it's a bad
thing, but I don't really understand why it's there. The
.so.debug file is made with the relevant objcopy utility
using --only-keep-debug from the libc-2.12.1.so file, which
is then stripped (--strip-unneeded), and with objcopy
--add-gnu-debuglink.
libthread_db is on target, so I don't really understand why
gdb doesn't like it.
(gdb) sig SIGABRT
Continuing with signal SIGABRT.
Received signal SIGABRT (6) in thread 0x00031460, TID 1933
Registers:
R0: 00000007 R1: 00000000 R2: 00000001 R3: 00000008
R4: 0000078d R5: 00000001 R6: 00031674 R7: 00000000
R8: 00000000 R9: bef26a98 R10: 00000001 FP: 00030bec
PC: 0000b540 IP: 00030638 SP: 00030bd0 LR: 402467e4
ERR: 00000817 CPSR: 20000010 FAULT: 00000008 TRAP: 0000000e
OLDMSK: 00000000
Program received signal SIGSEGV, Segmentation fault.
0x4026da98 in __errno_location () from /lib/libc.so.6
(gdb) bt
#0 0x4026da98 in __errno_location () from /lib/libc.so.6
#1 0x40294d0c in vfprintf () from /lib/libc.so.6
#2 0x40299284 in ?? () from /lib/libc.so.6
#3 0x40299284 in ?? () from /lib/libc.so.6
[and it goes on forever]
Has anyone else had any luck using libunwind with multithreaded arm
applications?
--
Henrik Grindal Bakken <[email protected]>
PGP ID: 8D436E52
Fingerprint: 131D 9590 F0CF 47EF 7963 02AF 9236 D25A 8D43 6E52
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