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From: Theodore Ts'o <tytso@mit.edu>
To: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>,
	linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>
Subject: Re: Excessive stall times on ext4 in 3.9-rc2
Date: Mon, 8 Apr 2013 07:01:12 -0400	[thread overview]
Message-ID: <20130408110112.GA8332@thunk.org> (raw)
In-Reply-To: <y0mwqsehuj9.fsf@fche.csb>

On Sun, Apr 07, 2013 at 05:59:06PM -0400, Frank Ch. Eigler wrote:
> > semantic error: while resolving probe point: identifier 'kprobe' at /tmp/stapdjN4_l:18:7
> >         source: probe kprobe.function("get_request_wait")
> >                       ^
> > Pass 2: analysis failed.  [man error::pass2]
> > Unexpected exit of STAP script at ./watch-dstate.pl line 296.
> > I have no clue what to do next.  Can you give me a hint?

Is there any reason why the error message couldn't be simplified, to
something as "kernel symbol not found"?  I wasn't sure if the problem
was that there was some incompatibility between a recent change with
kprobe and systemtap, or parse failure in the systemtap script, etc.

> Systemtap could endavour to list roughly-matching functions that do
> exist, if you think that's be helpful.

If the goal is ease of use, I suspect the more important thing that
systemtap could do is to make its error messages more easily
understandable, instead of pointing the user to read a man page where
the user then has to figure out which one of a number of failure
scenarios were caused by a particularly opaque error message.  (The
man page doesn't even say that "semantic error while resolving probe
point" means that a kernel function doesn't exist -- especially
complaining about the kprobe identifier points the user in the wrong
direction.)

							- Ted

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  parent reply	other threads:[~2013-04-08 11:01 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-02 14:27 Excessive stall times on ext4 in 3.9-rc2 Mel Gorman
2013-04-02 15:00 ` Jiri Slaby
2013-04-02 15:03 ` Zheng Liu
2013-04-02 15:15   ` Mel Gorman
2013-04-02 15:06 ` Theodore Ts'o
2013-04-02 15:14   ` Theodore Ts'o
2013-04-02 18:19     ` Theodore Ts'o
2013-04-07 21:59       ` Frank Ch. Eigler
2013-04-08  8:36         ` Mel Gorman
2013-04-08 10:52           ` Frank Ch. Eigler
2013-04-08 11:01         ` Theodore Ts'o [this message]
2013-04-03 10:19     ` Mel Gorman
2013-04-03 12:05       ` Theodore Ts'o
2013-04-03 15:15         ` Mel Gorman
2013-04-05 22:18       ` Jiri Slaby
2013-04-05 23:16         ` Theodore Ts'o
2013-04-06  7:29           ` Jiri Slaby
2013-04-06  7:37             ` Jiri Slaby
2013-04-06  8:19               ` Jiri Slaby
2013-04-06 13:15             ` Theodore Ts'o
2013-04-10 10:56   ` Mel Gorman
2013-04-10 13:12     ` Theodore Ts'o
2013-04-11 17:04       ` Mel Gorman
2013-04-11 18:35         ` Theodore Ts'o
2013-04-11 21:33           ` Jan Kara
2013-04-12  2:57             ` Theodore Ts'o
2013-04-12  4:50               ` Dave Chinner
2013-04-12 15:19                 ` Theodore Ts'o
2013-04-13  1:23                   ` Dave Chinner
2013-04-22 14:38                   ` Mel Gorman
2013-04-22 22:42                     ` Jeff Moyer
2013-04-23  0:02                       ` Theodore Ts'o
2013-04-23  9:31                       ` Jan Kara
2013-04-23 14:01                       ` Mel Gorman
2013-04-24 19:09                         ` Jeff Moyer
2013-04-25 12:21                           ` Mel Gorman
2013-04-12  9:47               ` Mel Gorman
2013-04-21  0:05                 ` Theodore Ts'o
2013-04-21  0:07                   ` [PATCH 1/3] ext4: mark all metadata I/O with REQ_META Theodore Ts'o
2013-04-21  0:07                     ` [PATCH 2/3] buffer: add BH_Prio and BH_Meta flags Theodore Ts'o
2013-04-21  0:07                     ` [PATCH 3/3] ext4: mark metadata blocks using bh flags Theodore Ts'o
2013-04-21  6:09                       ` Jiri Slaby
2013-04-21 19:55                         ` Theodore Ts'o
2013-04-21 20:48                           ` [PATCH 3/3 -v2] " Theodore Ts'o
2013-04-22 12:06                     ` [PATCH 1/3] ext4: mark all metadata I/O with REQ_META Zheng Liu
2013-04-23 15:33                   ` Excessive stall times on ext4 in 3.9-rc2 Mel Gorman
2013-04-23 15:50                     ` Theodore Ts'o
2013-04-23 16:13                       ` Mel Gorman
2013-04-12 10:18               ` Tvrtko Ursulin
2013-04-12  9:45           ` Mel Gorman
2013-04-02 23:16 ` Theodore Ts'o
2013-04-03 15:22   ` Mel Gorman

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