Re: Regression caused by loopback related patches in 4.14.95

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, Feb 27, 2019 at 11:30:22AM +0100, Jan Kara wrote:
> Hello!
> 
> Thanks for the detailed report and bisection!
> 
> On Wed 27-02-19 00:35:26, Thomas Lindroth wrote:
> > When I run "losetup --verbose --partscan --read-only --find
> > /mnt/gemini.61rn.3T/Backups/debian.raw" on a 4.14.103 system losetup
> > hangs for exactly 3 minutes. After the hang the loopback device works
> > like it should. The /mnt/gemini.61rn.3T mount is an ext4 fs on dm-crypt
> > on a spinning sata disk.
> > 
> > The hang was introduced in 4.14.95 and there are several loop related
> > patches in 4.14.95.  I bisected it down to commit
> > c1e63df4f30c3918476ac9bc594355b0e9629893 "loop: Get rid of
> > loop_index_mutex". Reverting that commit from 4.14.103 also fixes the
> > problem.
> 
> So as you mention below, all the problems with loop device deadlocks didn't
> get fixed in stable kernels as some changes were too intrusive for the
> stable tree. Now unfortunately the commit 0a42e99b58a "loop: Get rid of
> loop_index_mutex" that did get backported makes some deadlocks much easier
> to hit as I'm looking into that now. For example when partitions are reread in
> loop_set_status(), it takes just one process trying to open the loop device
> to deadlock the kernel.
> 
> Actually that commit got already reverted in 4.4 stable because I've
> pointed out to Greg earlier that it has a doubtful benefit without followup
> fixes. But sadly it remained in other stable branches. Now going through
> the active branches the summary seems to be:
> 
> 3.18 and older: never applied
> 4.4:  already reverted
> 4.9:  needs revert
> 4.14: needs revert
> 4.19 and newer: followup fixes applied
> 
> So Greg, can you please revert the same three commits that you've reverted
> in 4.4 also in 4.9 and 4.14 stable threes? These are:
> 
> 0a42e99b58a "loop: Get rid of loop_index_mutex"
> 967d1dc144b "loop: Fold __loop_release into loop_release"
> 628bd859470 "loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl()"

Now all reverted, sorry about this.

greg k-h



[Index of Archives]     [Linux RAID]     [Linux SCSI]     [Linux ATA RAID]     [IDE]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Device Mapper]

  Powered by Linux