Ok, I'll start a new thread with the details. I'm not so sure if this is
actually
related to Xenomai, but until now I was only able to reproduce it in
conjunction with
xenomai libs, so ...
The example is already reduced to a minimum. I'm working with a Blackfin-based
board like BF537-STAMP, with 2010R1-RC5 blackfin-linux-dist on it and stock
kernel
as it comes with the dist (2.6.34.7-ADI-2010R1). Just Xenomai 2.5.3 was replaced
by 2.5.5.2. Toolchain is 2010R1-RC4 taken as binary from blackfin.uclinux.org.
The code itself actually doesn't seem to matter. The problem can be reproduced
with an
example as simple as this "a.c":
int main (void) { return 0; }
Normally, this can be started on the target via gdbserver and debugged from the host.
I used the gdb command script
file a.out
target remote 10.0.10.9:2222
break main
cont
The target would run the example, and stop, e.g. at "Breakpoint 1, 0x00b7b626 in
main ()"
These compile commands produce a working a.out:
bfin-linux-uclibc-gcc -L/opt/uClinux/blackfin-linux-dist/staging/usr/lib
-lpthread a.c
or
bfin-linux-uclibc-gcc -L/opt/uClinux/blackfin-linux-dist/staging/usr/lib
-lpthread_rt -lxenomai a.c
but this one that combines all -l options above doesn't:
bfin-linux-uclibc-gcc -L/opt/uClinux/blackfin-linux-dist/staging/usr/lib
-lpthread_rt -lxenomai -lpthread a.c
(Adding -lrt, to complete the suggested posix-ldflags, doesn't help, so I omit
it here for shortness)
The result on the target, when started with gdbserver and as soon as the host
says "cont", is a NULL pointer access. It seems to occur even before main() is
reached.
Following is the complete output on the target:
/tmp # gdbserver :2222 ./a.out
Process ./a.out created; pid = 320
Listening on port 2222
Remote debugging from host 10.0.10.10
NULL pointer access
Deferred Exception context
CURRENT PROCESS:
COMM=a.out PID=320 CPU=0
TEXT = 0x00ea9000-0x00ea96c8 DATA = 0x00eaa6c8-0x00eaa834
BSS = 0x00eaa834-0x013a0000 USER-STACK = 0x013bfe60
return address: [0x01666f10]; contents of:
0x01666ef0: e42f 0015 0c07 1405 3047 67f8 e628 0015
0x01666f00: 320e 3044 300d 3014 e50a 003a 5ea2 9153
0x01666f10: [9159] ac5b 0061 0c07 1404 6000 e628 0015
0x01666f20: e801 0000 05a4 0010 e51a 0016 05f4 e800
ADSP-BF537-0.3 533(MHz CCLK) 133(MHz SCLK) (mpu off)
Linux version 2.6.34.7-ADI-2010R1-svn10663 (kawk@fee) (gcc version 4.3.5
(ADI-2010R1-RC4) ) #58 Mon Jan 24 17:24:55 CET 2011
SEQUENCER STATUS: Not tainted
SEQSTAT: 00060027 IPEND: 0008 IMASK: ffff SYSCFG: 0006
EXCAUSE : 0x27
physical IVG3 asserted : <0xffa0076c> { _trap + 0x0 }
RETE: <0x00000000> /* Maybe null pointer? */
RETN: <0x00b8a000> /* kernel dynamic memory */
RETX: <0x00000480> /* Maybe fixed code section */
RETS: <0x01666eda> [ /lib/libpthread.so.0 + 0x6eda ]
PC : <0x01666f10> [ /lib/libpthread.so.0 + 0x6f10 ]
DCPLB_FAULT_ADDR: <0x00000000> /* Maybe null pointer? */
ICPLB_FAULT_ADDR: <0x01666f10> [ /lib/libpthread.so.0 + 0x6f10 ]
PROCESSOR STATE:
R0 : 0000001c R1 : 013bd374 R2 : 013bd3f4 R3 : 00000008
R4 : 013bd3f4 R5 : 013bd374 R6 : 015e9448 R7 : 00000000
P0 : 000000ae P1 : 015e9448 P2 : 015e9650 P3 : 00000000
P4 : 0000001c P5 : 015e8b40 FP : 013bd340 SP : 00b89f24
LB0: 01620483 LT0: 01620482 LC0: 00000000
LB1: 016675a1 LT1: 01667578 LC1: 000003ff
B0 : 00000137 L0 : 00000000 M0 : 000000b4 I0 : 013bd6bc
B1 : 000000c0 L1 : 00000000 M1 : 00000001 I1 : 00000001
B2 : 7ffff000 L2 : 00000000 M2 : 00001802 I2 : 00000002
B3 : 00000000 L3 : 00000000 M3 : 0000005b I3 : 00000006
A0.w: 00000000 A0.x: 00000000 A1.w: 00000000 A1.x: 00000000
USP : 013bd330 ASTAT: 02003064
Hardware Trace:
0 Target : <0x00003bf8> { _trap_c + 0x0 }
Source : <0xffa00700> { _exception_to_level5 + 0xa4 } JUMP.L
1 Target : <0xffa0065c> { _exception_to_level5 + 0x0 }
Source : <0xffa00510> { _bfin_return_from_exception + 0x18 } RTX
2 Target : <0xffa004f8> { _bfin_return_from_exception + 0x0 }
Source : <0xffa005b4> { _ex_trap_c + 0x74 } JUMP.S
3 Target : <0xffa00540> { _ex_trap_c + 0x0 }
Source : <0xffa007c4> { _trap + 0x58 } JUMP (P4)
4 Target : <0xffa0076c> { _trap + 0x0 }
FAULT : <0x01666f10> [ /lib/libpthread.so.0 + 0x6f10 ] P1 = [P3]
Source : <0x01666f0e> [ /lib/libpthread.so.0 + 0x6f0e ] P3 = [P2]
5 Target : <0x01666eee> [ /lib/libpthread.so.0 + 0x6eee ]
Source : <0x01666ee2> [ /lib/libpthread.so.0 + 0x6ee2 ] IF CC JUMP pcrel
(BP)
6 Target : <0x01666eda> [ /lib/libpthread.so.0 + 0x6eda ]
Source : <0x01666e64> [ /lib/libpthread.so.0 + 0x6e64 ] RTS
7 Target : <0x01666e60> [ /lib/libpthread.so.0 + 0x6e60 ]
Source : <0x01666e3c> [ /lib/libpthread.so.0 + 0x6e3c ] JUMP.S
8 Target : <0x01666e18> [ /lib/libpthread.so.0 + 0x6e18 ]
Source : <0x01666ed6> [ /lib/libpthread.so.0 + 0x6ed6 ] CALL pcrel
9 Target : <0x01666ec8> [ /lib/libpthread.so.0 + 0x6ec8 ]
Source : <0xffa00d12> { __common_int_entry + 0xce } RTI
10 Target : <0xffa00cb0> { __common_int_entry + 0x6c }
Source : <0xffa00f80> { _evt_system_call + 0x64 } JUMP.S
11 Target : <0xffa00f80> { _evt_system_call + 0x64 }
Source : <0xffa00982> { _system_call + 0xee } RTS
12 Target : <0xffa0097c> { _system_call + 0xe8 }
Source : <0x000031fe> { _do_notify_resume + 0x52 } RTS
13 Target : <0x000031fa> { _do_notify_resume + 0x4e }
Source : <0x000031dc> { _do_notify_resume + 0x30 } IF CC JUMP pcrel (BP)
14 Target : <0x000031ce> { _do_notify_resume + 0x22 }
Source : <0x000031aa> { _do_signal + 0x126 } RTS
15 Target : <0x000031a0> { _do_signal + 0x11c }
Source : <0x00003118> { _do_signal + 0x94 } IF CC JUMP pcrel (BP)
Userspace Stack
Stack info:
SP: [0x013bd330] <0x013bd330> [ a.out + 0x1d330 ]
Memory from 0x013bd330 to 013be000
013bd330:[00000000] 00000000 00000000 00000000 013bd4d8 00000400 013bd638 00b8595c
013bd350: 013bd580 01599628 0000001c 013be86c 0000001c 013bd374 013bd3f4 00000000
013bd370: 00000000 0000001c 00000000 ffffffff 00000000 00000000 00000002 00000000
013bd390: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
013bd3b0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
...
013bdfb0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
013bdfd0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
013bdff0: 00000000 00000000 00000000 00000000
Return addresses in stack:
address : <0x01665f66> [ /lib/libpthread.so.0 + 0x5f66 ]
address : <0x0166759a> [ /lib/libpthread.so.0 + 0x759a ]
The specified locations RETS and PC
RETS: <0x01666eda> [ /lib/libpthread.so.0 + 0x6eda ]
PC : <0x01666f10> [ /lib/libpthread.so.0 + 0x6f10 ]
resolve to
0x6eda libpthread/linuxthreads.old/signals.c:113
0x6f10 libpthread/linuxthreads.old/signals.c:127
Kolja
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