On Fri, 2012-10-12 at 13:55 -0400, Sasha Levin wrote: > Hi Ben, > > On Wed, Oct 10, 2012 at 11:52 AM, Ben Hutchings <b...@decadent.org.uk> wrote: > > On Tue, 2012-10-09 at 09:26 -0400, Sasha Levin wrote: > >> On 10/09/2012 09:21 AM, Sasha Levin wrote: > >> > On 10/08/2012 05:45 PM, Jiri Kosina wrote: > >> >> On Mon, 8 Oct 2012, Jan Kara wrote: > >> >> > >> >>>>>> I'm still seeing this on linux-next. > >> >>>> I think this is floppy related (see redo_fd_request() in the stack > >> >>>> trace). And there were quite some changes to the area recently. Adding > >> >>>> maintainer to CC. > >> >> Hmm ... I don't immediately see how this is happening. > >> >> > >> >> Sasha, could you please do git bisect on drivers/block/floppy.c between > >> >> f6365201d and your git HEAD for starters (assuming that f6365201d works > >> >> well for you?). > >> >> > >> > > >> > A bisect on floppy.c yielded the following: > >> > > >> > b33d002f4b6bae912463e5a66387c498aa69b6fe is the first bad commit > >> > commit b33d002f4b6bae912463e5a66387c498aa69b6fe > >> > Author: Ben Hutchings <b...@decadent.org.uk> > >> > Date: Mon Aug 27 20:56:53 2012 -0300 > >> > > >> > genhd: Make put_disk() safe for disks that have not been registered [...] > > I see two problems: > > > > 1. redo_fd_request() races with tear-down of the disks, but because > > set_next_request() checks disk->queue before doing anything this was > > usually harmless. Now that do_floppy_init() doesn't clear disk->queue, > > the race condition is much easier to hit. This may fix that problem in > > do_floppy_init(), though there appear to be worse bugs in tear-down > > order in floppy_module_exit(): [...] > > 2. I made a big mistake in using the existing GENHD_FL_UP flag, as it is > > cleared by del_gendisk(). Incremental patch below, but it should be > > squashed into the previous patch if that branch is still rebase-able. [...] > I'm now seeing these instead: [...]
Sorry, I'm not going to spend more time in the quagmire of the floppy driver. Whoever has this commit in their tree, please revert or drop it as appropriate. Ben. -- Ben Hutchings No political challenge can be met by shopping. - George Monbiot
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