On Wed, Feb 22, 2017 at 11:24:25AM +0100, Jan Kara wrote: > On Tue 21-02-17 10:19:28, Jens Axboe wrote: > > On 02/21/2017 10:09 AM, Jan Kara wrote: > > > Hello, > > > > > > this is a second revision of the patch set to fix several different races and > > > issues I've found when testing device shutdown and reuse. The first three > > > patches are fixes to problems in my previous series fixing BDI lifetime issues. > > > Patch 4 fixes issues with reuse of BDI name with scsi devices. With it I cannot > > > reproduce the BDI name reuse issues using Omar's stress test using scsi_debug > > > so it can be used as a replacement of Dan's patches. Patches 5-11 fix oops that > > > is triggered by __blkdev_put() calling inode_detach_wb() too early (the problem > > > reported by Thiago). Patches 12 and 13 fix oops due to a bug in gendisk code > > > where get_gendisk() can return already freed gendisk structure (again triggered > > > by Omar's stress test). > > > > > > People, please have a look at patches. They are mostly simple however the > > > interactions are rather complex so I may have missed something. Also I'm > > > happy for any additional testing these patches can get - I've stressed them > > > with Omar's script, tested memcg writeback, tested static (not udev managed) > > > device inodes. > > > > > > Jens, I think at least patches 1-3 should go in together with my fixes you > > > already have in your tree (or shortly after them). It is up to you whether > > > you decide to delay my first fixes or pick these up quickly. Patch 4 is > > > (IMHO a cleaner) replacement of Dan's patches so consider whether you want > > > to use it instead of those patches. > > > > I have applied 1-3 to my for-linus branch, which will go in after > > the initial pull request has been pulled by Linus. Consider fixing up > > #4 so it applies, I like it. > > OK, attached is patch 4 rebased on top of Linus' tree from today which > already has linux-block changes pulled in. I've left put_disk_devt() in > blk_cleanup_queue() to maintain the logic in the original patch (now commit > 0dba1314d4f8) that request_queue and gendisk each hold one devt reference. > The bdi_unregister() call that is moved to del_gendisk() by this patch is > now protected by the gendisk reference instead of the request_queue one > so it still maintains the property that devt reference protects bdi > registration-unregistration lifetime (as much as that is not needed anymore > after this patch). > > I have also updated the comment in the code and the changelog - they were > somewhat stale after changes to the whole series Tejun suggested. > > Honza Hey, Jan, I just tested this out when I was seeing similar crashes with sr instead of sd, and this fixed it. Tested-by: Omar Sandoval <osandov@xxxxxx>
