I agree. The patch "dm: ensure bio submission follows a depth-first tree walk" doesn't really fix any bug (and it may introduce new bugs), so it isn't applicable to the stable kernel branches. The kernel 4.15 and below have a "dm_offload" mechanism that avoids the possible deadlocks in dm, there is no reason why this should be converted to the "depth-first tree walk". Mikulas On Thu, 22 Mar 2018, Mike Snitzer wrote: > On Thu, Mar 22 2018 at 9:06am -0400, > gregkh@xxxxxxxxxxxxxxxxxxx <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > This is a note to let you know that I've just added the patch titled > > > > dm: ensure bio submission follows a depth-first tree walk > > > > to the 4.15-stable tree which can be found at: > > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > > > The filename of the patch is: > > dm-ensure-bio-submission-follows-a-depth-first-tree-walk.patch > > and it can be found in the queue-4.15 subdirectory. > > > > If you, or anyone else, feels it should not be added to the stable tree, > > please let <stable@xxxxxxxxxxxxxxx> know about it. > > The following applies to 4.14 stable@ too. > > I think it very questionable to pull this into stable trees. How'd it > even elevate to be considered for stable@? > > But if you do, you definitely need this additional upstream commit: > 8dd601fa8317 ("dm: correctly handle chained bios in dec_pending()") > > Even with that I'm not excited about supporting some partial backport of > these changes because there were a lot more related changes -- only > taking a subset makes these stable@ kernels unicorns.. I deal with > enough unicorn vendor kernels (but on my terms, with my control over > what is "supportable"): > > Anyway, other related commits are: > 80cd17578310 dm crypt: remove BIOSET_NEED_RESCUER flag > c110a4b6e603 dm io: remove BIOSET_NEED_RESCUER flag from bios bioset > f31c21e4365c dm: remove unused 'num_write_bios' target interface > 318716ddea08 dm: safely allocate multiple bioset bios > 4a3f54d94d5c dm: remove BIOSET_NEED_RESCUER based dm_offload infrastructure > 0776aa0e30aa dm: ensure bio-based DM's bioset and io_pool support targets' maximum IOs > 3d7f45625a84 dm: fix __send_changing_extent_only() to send first bio and chain remainder > > So NAK from me. If others have a compelling argument I'm open to > considering. > > Mike > -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
