Messages in this thread | | | Date | Sun, 10 Mar 2013 14:40:09 -0700 | From | Greg KH <> | Subject | Re: kernel BUG at fs/sysfs/group.c:65! |
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On Sun, Mar 10, 2013 at 01:35:12PM -0700, Eric W. Biederman wrote: > Greg KH <gregkh@linuxfoundation.org> writes: > > > On Sun, Mar 10, 2013 at 04:53:11PM +0800, Ming Lei wrote: > >> On Sun, Mar 10, 2013 at 12:36 AM, Tommi Rantala <tt.rantala@gmail.com> wrote: > >> > [ 40.089036] [<ffffffff81222e29>] sysfs_get_dirent+0x39/0x80 > >> > [ 40.089036] [<ffffffff81224ad9>] sysfs_remove_group+0x29/0x100 > >> > [ 40.089036] [<ffffffff8113f2c4>] blk_trace_remove_sysfs+0x14/0x20 > >> > [ 40.089036] [<ffffffff813453ae>] blk_unregister_queue+0x5e/0x90 > >> > [ 40.089036] [<ffffffff8134d417>] del_gendisk+0x107/0x250 > >> > [ 40.089036] [<ffffffff814f66b8>] loop_remove+0x18/0x40 > >> > >> Then the crash is triggered in device release path, which should have > >> been avoided in device add path. > >> > >> If we want to fix the problem completely, add_disk() must handle failure > >> path correctly and return error code on failures, which may involve big > >> work, since add_disk() are called by 50+ drivers. > > > > Ok, but the root problem here is add_disk() is being called to create a > > disk that was already created, right? Surely the caller should have > > detected this before it called to the block core? > > > > Who is calling add_disk() here? Is this a fuse device? If so, then any > > user can trigger this, right? > > > > That should be the "easier" fix at the moment to resolve this issue. > > At first glance this looks like rances in the loop driver.
Then that should be easy to fix, only allow one loop device to be created / removed at a time?
greg k-h
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