Re: just-in-time debugging?
My approach is something like the others. I developed a small wrapper to catch unaligned traps on alpha. What it does is run a program in gdb with some specified arguments (it also sets up so that the process gets a SIGBUS when it does an unaligned access, but that's probably not relevant here). Any case, its available by anonymous ftp at ftp://uncarved.com/unaligned.c in case you're interested... Sean On Sat, Apr 28, 2001 at 09:17:10PM +0100, Tony Hoyle wrote: > Is there a way (kernel or userspace... doesn't matter) that gdb/ddd > could be invoked when a program is about > to dump core, or perhaps on a certain signal (that the app could deliver > to itself when required). The latter case > is what I need right now, as I have to debug an app that breaks > seemingly randomly & I need to halt when > certain assertions fail. Core dumps aren't much use as you can't resume > them, otherwise I'd just force a segfault > or something. > > I had a look at the do_coredump stuff and it looks like it could be > altered to call gdb in the same way that > modprobe gets called by kmod... however I don't sufficiently know the > code to work out whether it'd work properly > or not. > > A patch to glibc would perhaps be better, but I know that code even > less! > > Something like responding to SIGTRAP would probably be ideal. > > Tony > > -- > > "Two weeks before due date, the programmers work 22 hour days cobbling an > application from... (apparently) one programmer bashing his face into the > keyboard." -- Dilbert > > [EMAIL PROTECTED]http://www.nothing-on.tv > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: just-in-time debugging?
My approach is something like the others. I developed a small wrapper to catch unaligned traps on alpha. What it does is run a program in gdb with some specified arguments (it also sets up so that the process gets a SIGBUS when it does an unaligned access, but that's probably not relevant here). Any case, its available by anonymous ftp at ftp://uncarved.com/unaligned.c in case you're interested... Sean On Sat, Apr 28, 2001 at 09:17:10PM +0100, Tony Hoyle wrote: Is there a way (kernel or userspace... doesn't matter) that gdb/ddd could be invoked when a program is about to dump core, or perhaps on a certain signal (that the app could deliver to itself when required). The latter case is what I need right now, as I have to debug an app that breaks seemingly randomly I need to halt when certain assertions fail. Core dumps aren't much use as you can't resume them, otherwise I'd just force a segfault or something. I had a look at the do_coredump stuff and it looks like it could be altered to call gdb in the same way that modprobe gets called by kmod... however I don't sufficiently know the code to work out whether it'd work properly or not. A patch to glibc would perhaps be better, but I know that code even less! Something like responding to SIGTRAP would probably be ideal. Tony -- Two weeks before due date, the programmers work 22 hour days cobbling an application from... (apparently) one programmer bashing his face into the keyboard. -- Dilbert [EMAIL PROTECTED]http://www.nothing-on.tv - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
RE: just-in-time debugging?
On 28-Apr-2001 Tony Hoyle wrote: > On 28 Apr 2001 13:44:48 -0700, Davide Libenzi wrote: >> Sorry but why don't You run Your application with gdb ? >> Once Your program crashes You'll get the prompt and You'll be able to >> stack-trace and watching whatever You need. >> The solution I use to be able to get inside the program even when the gdb is >> not running is the one that You can find in the attached file. >> Basically it install the handler that will create a script file that You can >> use to automatically enter with gdb inside Your program while it's running. > > > > Because the program is invoked as part of a much larger system & I don't > > know which process is going to crash when. > > Having gdb come up automatically would greatly decrease development > time. I'm trying to track down multiple bugs (caused by me, but they > still need tracking down) which show up during stress testing. The bug > will manifest itself in maybe the 1000th iteration... If I could hack > gdb into coming up automatically when things went wrong it'd get rid of > the need to have thousands of printf's in the app (which is my primary > debugging tool at the moment). > > At work I do this all the time... Windows pops up a dialog which > basically says 'the program has crashed, debug?' and drops you straight > into VC with everything intact. It has assertion macros which wrap int3 > instructions. You then continue your app under normal debug conditions. Just check the code I sent, it works fine for Your needs. - Davide - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
RE: just-in-time debugging?
On 28 Apr 2001 13:44:48 -0700, Davide Libenzi wrote: > Sorry but why don't You run Your application with gdb ? > Once Your program crashes You'll get the prompt and You'll be able to > stack-trace and watching whatever You need. > The solution I use to be able to get inside the program even when the gdb is > not running is the one that You can find in the attached file. > Basically it install the handler that will create a script file that You can > use to automatically enter with gdb inside Your program while it's running. Because the program is invoked as part of a much larger system & I don't know which process is going to crash when. Having gdb come up automatically would greatly decrease development time. I'm trying to track down multiple bugs (caused by me, but they still need tracking down) which show up during stress testing. The bug will manifest itself in maybe the 1000th iteration... If I could hack gdb into coming up automatically when things went wrong it'd get rid of the need to have thousands of printf's in the app (which is my primary debugging tool at the moment). At work I do this all the time... Windows pops up a dialog which basically says 'the program has crashed, debug?' and drops you straight into VC with everything intact. It has assertion macros which wrap int3 instructions. You then continue your app under normal debug conditions. Tony (Fighting with evolution because Mozilla broke imap again... sigh...) -- "Two weeks before due date, the programmers work 22 hour days cobbling an application from... (apparently) one programmer bashing his face into the keyboard." -- Dilbert [EMAIL PROTECTED]http://www.nothing-on.tv - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
RE: just-in-time debugging?
On 28-Apr-2001 Tony Hoyle wrote: > Is there a way (kernel or userspace... doesn't matter) that gdb/ddd > could be invoked when a program is about > to dump core, or perhaps on a certain signal (that the app could deliver > to itself when required). The latter case > is what I need right now, as I have to debug an app that breaks > seemingly randomly & I need to halt when > certain assertions fail. Core dumps aren't much use as you can't resume > them, otherwise I'd just force a segfault > or something. > > I had a look at the do_coredump stuff and it looks like it could be > altered to call gdb in the same way that > modprobe gets called by kmod... however I don't sufficiently know the > code to work out whether it'd work properly > or not. Sorry but why don't You run Your application with gdb ? Once Your program crashes You'll get the prompt and You'll be able to stack-trace and watching whatever You need. The solution I use to be able to get inside the program even when the gdb is not running is the one that You can find in the attached file. Basically it install the handler that will create a script file that You can use to automatically enter with gdb inside Your program while it's running. - Davide GdbHook.cpp
Re: just-in-time debugging?
Tony Hoyle ([EMAIL PROTECTED]) wrote:
> Is there a way that gdb/ddd could be invoked when a program is about
> to dump core...?
Yes, I use that to get a symbolic stack dump after a crash,
although I find that the gdb so invoked doesn't accept interactive
commands, and I have to use 'kill -9' afterwards.
Here's the code I use:
void dump_stack(int signum)
{
(void) signum;
char s[160];
// The right command to execute depends on the program. Adjust to taste.
system("echo 'info threads\nbt\nthread 3\nbt\nthread 4\nbt\nthread 5\nbt\n' >
gdbcmd");
sprintf(s, "gdb -batch -x gdbcmd %s %d", argv0, (int) getpid());
printf("Crashed! Starting debugger to get stack dump. You may need to kill -9
this process afterwards.\n");
system(s);
exit(1);
}
main() {
signal(SIGSEGV, dump_stack);
signal(SIGBUS, dump_stack);
...
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
just-in-time debugging?
Is there a way (kernel or userspace... doesn't matter) that gdb/ddd could be invoked when a program is about to dump core, or perhaps on a certain signal (that the app could deliver to itself when required). The latter case is what I need right now, as I have to debug an app that breaks seemingly randomly & I need to halt when certain assertions fail. Core dumps aren't much use as you can't resume them, otherwise I'd just force a segfault or something. I had a look at the do_coredump stuff and it looks like it could be altered to call gdb in the same way that modprobe gets called by kmod... however I don't sufficiently know the code to work out whether it'd work properly or not. A patch to glibc would perhaps be better, but I know that code even less! Something like responding to SIGTRAP would probably be ideal. Tony -- "Two weeks before due date, the programmers work 22 hour days cobbling an application from... (apparently) one programmer bashing his face into the keyboard." -- Dilbert [EMAIL PROTECTED]http://www.nothing-on.tv - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: just-in-time debugging?
Tony Hoyle ([EMAIL PROTECTED]) wrote:
Is there a way that gdb/ddd could be invoked when a program is about
to dump core...?
Yes, I use that to get a symbolic stack dump after a crash,
although I find that the gdb so invoked doesn't accept interactive
commands, and I have to use 'kill -9' afterwards.
Here's the code I use:
void dump_stack(int signum)
{
(void) signum;
char s[160];
// The right command to execute depends on the program. Adjust to taste.
system(echo 'info threads\nbt\nthread 3\nbt\nthread 4\nbt\nthread 5\nbt\n'
gdbcmd);
sprintf(s, gdb -batch -x gdbcmd %s %d, argv0, (int) getpid());
printf(Crashed! Starting debugger to get stack dump. You may need to kill -9
this process afterwards.\n);
system(s);
exit(1);
}
main() {
signal(SIGSEGV, dump_stack);
signal(SIGBUS, dump_stack);
...
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
RE: just-in-time debugging?
On 28-Apr-2001 Tony Hoyle wrote: Is there a way (kernel or userspace... doesn't matter) that gdb/ddd could be invoked when a program is about to dump core, or perhaps on a certain signal (that the app could deliver to itself when required). The latter case is what I need right now, as I have to debug an app that breaks seemingly randomly I need to halt when certain assertions fail. Core dumps aren't much use as you can't resume them, otherwise I'd just force a segfault or something. I had a look at the do_coredump stuff and it looks like it could be altered to call gdb in the same way that modprobe gets called by kmod... however I don't sufficiently know the code to work out whether it'd work properly or not. Sorry but why don't You run Your application with gdb ? Once Your program crashes You'll get the prompt and You'll be able to stack-trace and watching whatever You need. The solution I use to be able to get inside the program even when the gdb is not running is the one that You can find in the attached file. Basically it install the handler that will create a script file that You can use to automatically enter with gdb inside Your program while it's running. - Davide GdbHook.cpp
RE: just-in-time debugging?
On 28-Apr-2001 Tony Hoyle wrote: On 28 Apr 2001 13:44:48 -0700, Davide Libenzi wrote: Sorry but why don't You run Your application with gdb ? Once Your program crashes You'll get the prompt and You'll be able to stack-trace and watching whatever You need. The solution I use to be able to get inside the program even when the gdb is not running is the one that You can find in the attached file. Basically it install the handler that will create a script file that You can use to automatically enter with gdb inside Your program while it's running. Because the program is invoked as part of a much larger system I don't know which process is going to crash when. Having gdb come up automatically would greatly decrease development time. I'm trying to track down multiple bugs (caused by me, but they still need tracking down) which show up during stress testing. The bug will manifest itself in maybe the 1000th iteration... If I could hack gdb into coming up automatically when things went wrong it'd get rid of the need to have thousands of printf's in the app (which is my primary debugging tool at the moment). At work I do this all the time... Windows pops up a dialog which basically says 'the program has crashed, debug?' and drops you straight into VC with everything intact. It has assertion macros which wrap int3 instructions. You then continue your app under normal debug conditions. Just check the code I sent, it works fine for Your needs. - Davide - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
