gdb stack trace shows only those frames after the signal
srikrish
srikrish@in.ibm.com
Tue Dec 23 14:56:00 GMT 2003
Hi,After handling a signal the previous stack trace is lost. Is this a known problem? Any fixes?Hardware Environment: Intel
x86Software Environment:Linux RHEL 3; gdb-5.3.90-0.20030710.40rh; glibc 2.3.2-95.6; gcc 3.2.3 20030502 Also occurs with SuSE
Linux.Steps to Reproduce:1. compile the testcase (under Additinal Info below) with "gcc -o t mytrap.c"2. run "t"3. attach gdb to the
"t"'s PID and type "where"Actual Results:[root@localhost root]# gdbGNU gdb Red Hat Linux (5.3.90-0.20030710.40rh)This GDB was
configured as "i386-redhat-linux-gnu".(gdb) attach 2032Attaching to process 2032Reading symbols from /home/krishna/t...done.Using
host libthread_db library "/lib/libthread_db.so.1".Reading symbols from /lib/libc.so.6...done.Loaded symbols for
/lib/libc.so.6Reading symbols from /lib/ld-linux.so.2...done.Loaded symbols for /lib/ld-linux.so.20xb755d8cb in pause () from
/lib/libc.so.6(gdb) where#0 0xb755d8cb in pause () from /lib/libc.so.6#1 0x0804840f in function2 () at mytrap.c:8#2 0x0804842c in
function1 () at mytrap.c:15#3 0x08048449 in SIGSEGVhandler (sig=11, info=0xbfffa5a0, ucontext=0xbfffa620) at mytrap.c:22#4
<signal handler called>(gdb) frame 5#0 0x00000000 in ?? ()(gdb)Expected Results:the stack traceback should display functionb,
functiona, and main for this testcasemytrap.c:#include <stdio.h>#include <signal.h>#include <unistd.h>void function2( void ){
printf( "Now in function2.. pausing.. pid = %d\n", getpid() ); pause();}void function1( void ){ printf( "Now in function1\n" );
function2();}void SIGSEGVhandler( int sig, siginfo_t *info, void *ucontext ){ printf( "Now in SIGSEGVhandler\n" );
function1();}void functionb( void ){ char *p = NULL; printf( "Now in functionb... causing sig11...\n" ); *p = 'x'; /* forcing
SEGFAULT */}void functiona( void ){ printf( "Now in functiona\n" ); functionb();}int main( void ){ struct sigaction newact;
struct sigaction oldact; newact.sa_sigaction = SIGSEGVhandler; newact.sa_flags = SA_SIGINFO; sigaction( SIGSEGV, &newact,
&oldact ); printf( "About to call functiona\n" ); functiona(); return 0;}Srikrishnan
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