Older blog entries for Zaitcev (starting at number 409)

Unpleasant mass updates

Mass updates to Bugzilla have a few unpleasant side effects:

• Unless they're done by DKL with direct access to the database, they generate a lot of e-mail which buries actual updates.
• They destroy the usability of queries for "bugs modified in the last 60/45/30 days". It's a useful trick I learned from Arjan. But now all kernel bugs are recently modified.

The idea, I guess, is that developer has to rescan relevant bugs and either work on them, push them into NEEDINFO, or close them. If hackers are dilligent about it, auto-closer is harmless [and also, unnecessary -- ed]. In reality though, it just does not work that way [and the very existence of auto-closer is the proof -- ed]. At certain point, I started making extra-Bugzilla lists of bugs which look realistic to work on (e.g. have an active submitter who cooperates, for one thing). The rest just rots. I don't even have cycles to push WONTFIX on them (or, actually, I have time to close, but I don't want to deal with the fallout, so I just pretend not to see them -- the task made easier by the mass-update and the resulting mail avalanche).

P.S. My list of bugs is, like, 10 to 50 times smaller than Chuck's and DaveJ's. I don't understand how they cope. It seems impossible to me, so there must be some trade secret good kernel monkeys know.

Syndicated 2008-04-14 22:45:03 (Updated 2008-04-14 22:46:34) from Pete Zaitcev

The Belgian paper

Completely useless. Gee, the thugs running worst shitholes of the world can forge documents signed by children and make all their Web access trackable and non-refutable. Dog bites man. We knew before this paper that they condition children to carry their own telescreens. The only thing I want to know about the BitFrost is how to defeat it, and the paper doesn't say. Useless.

Syndicated 2008-04-09 15:51:11 from Pete Zaitcev

Timeouts

I didn't try to burn a CD with ub in a while, because my new laptop comes with a built-in burner. After all the hustling with __blk_end_request, I thought the situation called for a test. This looked worrysome:

Track 01: Total bytes read/written: 548321280/548321280 (267735 sectors).
Errno: 5 (Input/output error), close track/session scsi sendcmd: cmd timeout after 5.000 (480) s
CDB:  5B 00 02 00 00 00 00 00 00 00
cmd finished after 5.000s timeout 480s
cmd finished after 5.000s timeout 480s
wodim: Cannot fixate disk.

The resulting CD was not a coaster though. A welcome surprise, but clearly I did something wrong regarding timeouts, and it needs fixing (although I'm quite sure that there's no other person on Earth who would want to burn CDs with ub).

BTW, the new cdrecord looks nice indeed. Before, I only used the one maintained by that self-centered dude with attitude... No idea who maintains this one, but it seems working ok.

Syndicated 2008-04-07 03:28:25 from Pete Zaitcev

What Would Rusty Say?

One of the many great things Rusty has done was introducing the Misuse Levels of APIs (in OLS 03 keynote, slide 30 and beyond). I had a run-in with something of that nature last week.

Here's an interface:

/**
 * blk_end_request - Helper function for drivers to complete the request.
 * @rq:       the request being processed
 * @error:    0 for success, < 0 for error
 * @nr_bytes: number of bytes to complete
 *
 * Description:
 *     Ends I/O on a number of bytes attached to @rq.
 *     If @rq has leftover, sets it up for the next range of segments.
 *
 * Return:
 *     0 - we are done with this request
 *     1 - still buffers pending for this request
 **/
int blk_end_request(struct request *rq, int error, unsigned int nr_bytes)

What do you think the "number of bytes to complete" is? It seemed natural to me that it's the number of bytes which was transferred (and thus, it can be smaller than the number of bytes remembered in the request). This is how I would design an API. But in this case, nr_bytes is the number of bytes which was in the request initially. As such, it is greater than the request->data_len, which drivers modify to indicate the residue.

I think this has something to do with Tomo's & Jens' desire to avoid modifying drivers which poke ->data_len today (indeed, the code doing so in ub remained unchanged). If so, the price is too steep, IMHO.

Curiously, the designers of the API themselves misused it when they converted ub. They called __blk_end_request() with and argument of blk_rq_bytes(rq), but since ub modifies ->data_len, it guaranteed a failure for packet requests.

Everything seems to be working now, but I suspect that 2.6.25 is going to ship with a broken ub (thank Chris Wright for the Stable Tree).

UPDATE: See also a blog article (same server, but helps if Rusty decides to reshuffle his home directory).

Syndicated 2008-03-22 04:49:37 (Updated 2008-04-02 00:22:24) from Pete Zaitcev

Irony of the day

Seen today:

  PID USER      PR  NI  VIRT  RES  S %CPU %MEM    TIME+  COMMAND
23015 root      20   0  311m  63m  S  1.0  7.4 148:50.50 Xorg   
23661 zaitcev   20   0  446m 9324  S  1.0  1.1 117:00.18 gnome-power-man

So, the process which is supposed to save my CPU cycles is responsible for consuming almost as much as X server, which does a heck of a lot of work. Isn't it ironic?

I suspect Gnome Power Manager loses its mind when I close the lid overnight.

Syndicated 2008-03-21 05:04:59 from Pete Zaitcev

The LJ dorama

I welcome the deprecation of "free" LJ accounts. I always found it unfair and unsustainable how paying users subsidized unpaid users. As for Brad, being a former honcho gives him some insight points, but not too many. Look at Craig, does he blog about dumb people turning his website into something he does not like?

Syndicated 2008-03-18 23:29:39 from Pete Zaitcev

When release is not

Spent a weekend on a bug which looked like some interesting race, but in fact was just a simple logic error. Result is a trivial one line patch, I'm two days older and not an iota smarter.

BTW, our input subsystem is really convoluted. I'm not surprised bugs like this happen.

Syndicated 2008-03-18 07:33:00 from Pete Zaitcev

LOL X11

A minute ago I pulled a mouse out of my laptop and the X server crashed. The last messages in Xorg.0.log were:

(EE) Read error: No such device (19, -1 != 24)
(II) Microsoft Microsoft USB Wireless Mouse: Off

This happened because Xorg server 1.4.99.1 force-loads evdev contrary to my xorg.conf, and we all know that evdev is a crash city.

It's a good thing I was born and raised back when this sort of thing was expected every day, so X cannot catch me with a half-entered bug report in a browser. Also, it seems that Vim finally learned to remove dead .swp files without annoying users.

Syndicated 2008-03-06 01:15:23 from Pete Zaitcev

GNOME does something right

Today I plugged my iPod in, and Rawhide launched Rhythmbox, which chugged along for about half a minute, then crashed. At least it did not wipe the player's database. WTF, I thought I had all auto-run types set to off...

Looks like there were some changes. No more unchecking umpteenth type of crashware.

To compensate for a good thing, they worked extra hard to hide this panel. It's not reacheable from any parts of System menu. File Browser has to be started, and its Preferences adjusted.

UPDATE: The last part is untrue, I missed the right item. Thanks ucc_journal for the correction.

Syndicated 2008-02-12 21:24:21 (Updated 2008-02-13 04:40:52) from Pete Zaitcev

GNOME lies to me

Every time I log in, it promises not to show the message again, but then does.

I suppose I should clean some keys in gconf-editor, but which?

Also, tinkering with the registry is so Windows.

Syndicated 2008-02-08 17:40:53 from Pete Zaitcev