From: Jens Axboe <axboe@suse.de>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Daniel Phillips <phillips@arcor.de>,
Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
David Brownell <david-b@pacbell.net>,
Matthew Dharm <mdharm-kernel@one-eyed-alien.net>,
Greg KH <greg@kroah.com>,
linux-usb-devel@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: [linux-usb-devel] Re: [BK PATCH] USB changes for 2.5.34
Date: Mon, 16 Sep 2002 16:53:44 +0200 [thread overview]
Message-ID: <20020916145344.GN12364@suse.de> (raw)
In-Reply-To: <24433.1032185643@redhat.com>
On Mon, Sep 16 2002, David Woodhouse wrote:
>
> axboe@suse.de said:
> > See, even though I'm not fundamentally against using kernel
> > debuggers, I think this is very wrong. Where are you now? You are just
> > learning about the bio interface and the changes needed to make it
> > run. And this is definitely the most wrong point to start using a
> > debugger, and can only result in a dac960 that works by trial and
> > error.
>
> Nevertheless, the existence of a case where it's not sensible to use a
> debugger does not prove the non-existence of cases where it _is_ sensible
> to use a debugger.
>
> A case that happened to me recently -- tail-call optimisations screwed up
> the return value of a function somewhere deep in the routing code. Adding a
> printk made the problem go away. Staring at the C code was also of no use --
> the C code was just fine.
>
> Now, are you seriously suggesting that instead of using GDB to work out WTF
> was going on I should have spent three weeks starting at the output of
> 'objdump -d vmlinux' ?
I'm not suggesting anything for your case, and I'm not arguing against
kernel debuggers. Please re-read what I wrote: using a debugger for what
Daniel is attempting right now is stupid. Are you seriously suggesting
that you would trust your data to a driver that had been ported to 2.5,
not by studying the interface changes but by 'code blow up, gdb
inspection' method? I hope not.
I've used a kernel debugger a few times, for the things I tend to do
it's not very helpful. Or let me rephrase that into saying that it's not
more helpful than simply having the kernel compiled with -g and using
gdb on the resulting vmlinux just for backtraces and code inspection. So
I'm fine, and so I don't care very much about the typical pro/con
integrated debugger debates.
--
Jens Axboe
next prev parent reply other threads:[~2002-09-16 14:49 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-09 22:17 [BK PATCH] USB changes for 2.5.34 Greg KH
2002-09-10 0:17 ` Linus Torvalds
2002-09-10 0:19 ` Greg KH
2002-09-10 0:30 ` Linus Torvalds
2002-09-10 0:40 ` [linux-usb-devel] " Alan Cox
2002-09-10 1:41 ` Linus Torvalds
2002-09-10 1:48 ` Linus Torvalds
2002-09-10 10:23 ` Andries Brouwer
2002-09-10 0:35 ` Nicholas Miell
2002-09-10 1:01 ` [patch] dump_stack(): arch-neutral stack trace Andrew Morton
2002-09-15 4:34 ` Daniel Phillips
2002-09-15 4:51 ` Andrew Morton
2002-09-10 1:27 ` [BK PATCH] USB changes for 2.5.34 Linus Torvalds
2002-09-10 2:07 ` Matthew Dharm
2002-09-10 2:49 ` Linus Torvalds
2002-09-10 2:59 ` Linus Torvalds
2002-09-10 16:32 ` [linux-usb-devel] " David Brownell
2002-09-10 16:51 ` Linus Torvalds
2002-09-10 17:16 ` Jeff Garzik
2002-09-10 18:16 ` David S. Miller
2002-09-10 18:40 ` Linus Torvalds
2002-09-10 18:48 ` Jeff Garzik
2002-09-10 19:31 ` David S. Miller
2002-09-10 19:32 ` Oliver Xymoron
2002-09-10 19:38 ` Linus Torvalds
2002-09-10 19:43 ` Jeff Garzik
2002-09-10 21:52 ` Bill Davidsen
2002-09-10 22:02 ` Jeff Garzik
2002-09-10 18:44 ` Alan Cox
2002-09-10 19:03 ` Linus Torvalds
2002-09-10 19:27 ` Rik van Riel
2002-09-10 20:18 ` Alan Cox
2002-09-10 22:00 ` David Woodhouse
2002-09-10 22:23 ` Alan Cox
2002-09-10 22:26 ` David Woodhouse
2002-09-10 23:01 ` Alan Cox
2002-09-10 19:29 ` David S. Miller
2002-09-15 5:10 ` Daniel Phillips
2002-09-15 5:33 ` Daniel Berlin
2002-09-15 16:41 ` Daniel Phillips
2002-09-16 0:32 ` Horst von Brand
2002-09-15 6:07 ` Pete Zaitcev
2002-09-15 7:00 ` Andrew Morton
2002-09-15 14:53 ` Daniel Phillips
2002-09-15 18:23 ` Pete Zaitcev
2002-09-15 18:34 ` Jeff Garzik
2002-09-16 0:55 ` Larry McVoy
2002-09-15 20:05 ` David Woodhouse
2002-09-15 21:35 ` Rob Landley
2002-09-16 3:00 ` Larry McVoy
2002-09-16 3:08 ` Daniel Phillips
2002-09-16 11:16 ` Henning P. Schmiedehausen
2002-09-16 18:35 ` Thunder from the hill
2002-09-16 18:45 ` Daniel Phillips
2002-09-16 19:36 ` Thunder from the hill
2002-09-16 19:40 ` Daniel Phillips
2002-09-16 8:50 ` Ian Molton
2002-09-16 9:37 ` Rob Landley
2002-09-15 18:06 ` Linus Torvalds
2002-09-15 18:36 ` Roman Zippel
2002-09-15 19:04 ` Daniel Jacobowitz
2002-09-15 19:43 ` Andrew Morton
2002-09-15 19:43 ` Daniel Phillips
2002-09-15 23:24 ` Larry McVoy
2002-09-15 23:41 ` Daniel Jacobowitz
2002-09-15 23:52 ` Larry McVoy
2002-09-16 0:01 ` Robert Love
2002-09-16 1:29 ` Alan Cox
2002-09-16 2:13 ` Larry McVoy
2002-09-16 11:05 ` Henning P. Schmiedehausen
2002-09-16 14:05 ` Rogier Wolff
2002-09-16 16:24 ` Marco Colombo
2002-09-16 0:44 ` Daniel Phillips
2002-09-16 1:23 ` Alan Cox
2002-09-15 19:07 ` Daniel Phillips
2002-09-16 9:06 ` Jens Axboe
2002-09-16 15:15 ` Daniel Phillips
2002-09-16 15:59 ` kernel debuggers was [Re: [linux-usb-devel] Re: [BK PATCH] USB changes for 2.5.34] Soewono Effendi
2002-09-16 14:14 ` [linux-usb-devel] Re: [BK PATCH] USB changes for 2.5.34 David Woodhouse
2002-09-16 14:53 ` Jens Axboe [this message]
2002-09-15 19:08 ` Linus Torvalds
2002-09-15 19:10 ` Daniel Phillips
2002-09-15 19:26 ` Linus Torvalds
2002-09-15 19:32 ` Daniel Jacobowitz
2002-09-15 19:48 ` Daniel Phillips
2002-09-16 4:59 ` Jeff Dike
2002-09-16 4:05 ` Daniel Phillips
2002-09-16 4:55 ` Jeff Dike
2002-09-15 19:35 ` Daniel Phillips
2002-09-16 4:51 ` Jeff Dike
2002-09-16 15:29 ` Oliver Xymoron
2002-09-18 0:33 ` Rusty Russell
2002-09-18 0:46 ` Linus Torvalds
2002-09-18 0:50 ` Daniel Phillips
2002-09-18 1:16 ` Rik van Riel
2002-09-15 13:54 ` Rogier Wolff
2002-09-15 5:01 ` Daniel Phillips
2002-09-10 16:46 ` Thunder from the hill
2002-09-10 16:56 ` Vojtech Pavlik
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