Messages in this thread | | | Date | Thu, 22 Jul 2004 19:40:17 -0200 | From | Jens Axboe <> | Subject | Re: audio cd writing causes massive swap and crash |
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On Thu, Jul 22 2004, Ed Sweetman wrote: > Martin Schlemmer wrote: > > >On Thu, 2004-07-22 at 14:54, Jens Axboe wrote: > > > > > >>On Thu, Jul 22 2004, Ed Sweetman wrote: > >> > >> > >>>I've had other people test writing. It appears that scsi-emu is not > >>>effected by this memory leak when writing audio cds. So it would appear > >>>that ide-cd along with any of the dependent ide source files is the > >>>culprit. But I cannot find anywhere in ide-cd that is apparent to being > >>>a mem leak. There are various conditions in ide_do_drive_cmd that state > >>>that the cdrom driver has to be very careful about handling but without > >>>intimate knowledge of the driver, I can't be sure that it's sufficiently > >>>handling those situations. > >>> > >>>Surprisingly, it's very hard to find anyone who's used the native atapi > >>>mode to write an audio cd in 2.6. Which is partly why this problem > >>>hasn't generated more mail traffic here I would guess. > >>> > >>> > >>That's not true, lots of people use it. But, oddly, the leak isn't > >>reproducable on any machine I've tested. > >> > >> > > > >I seem to remember he noted a patch about dma during audio writing, > >and his 'testing' if it might be the cause was to just disable dma > >on the drive ... > > > > > > > The patch is now part of vanilla 2.6. It was an audio dma api that was > a workaround for the broken dma api that only allows ide commands > 512bytes long. Schilling mentioned something about this in an earlier > lkml posting around january. > > I've asked some other people in an irc channel to test out the problem. > Basically You need to be using the native atapi method for recording > audio. Also, it appears that the mem leak is just what happens to some > people, other people like some of those who tested in the irc channel > experienced random program sigsevs and no mem leak at all. It would > appear from this that what may be happening is the cdrom ide module is > mangling a pointer and either can't free it due to it possibly randomly > pointing to null or cause crashes due to it randomly pointing to other > anonymous/shared memory regions as kfree is called. That's obviously > just a guess. But some sort of memory mangling is apparently > happening. This is not just happening on my computer. > > > My drive is using udma33 and not mdma so maybe that makes the problem > occur more quickly. I disabled dma to test it writing the old way but > it appears to be occuring in ide-cd or somewhere between cdrom.o and the > block device layer. ide-scsi people dont have the problem at all > apparently.
Does turning on all the debug options (memory related, mostly) reveal anything interesting?
-- Jens Axboe
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