On Mon, 2022-11-21 at 08:35 -0500, Benjamin Coddington wrote: > Since moving to memalloc_nofs_save/restore, SUNRPC has stopped setting the > GFP_NOIO flag on sk_allocation which the networking system uses to decide > when it is safe to use current->task_frag. The results of this are > unexpected corruption in task_frag when SUNRPC is involved in memory > reclaim. > > The corruption can be seen in crashes, but the root cause is often > difficult to ascertain as a crashing machine's stack trace will have no > evidence of being near NFS or SUNRPC code. I believe this problem to > be much more pervasive than reports to the community may indicate. > > Fix this by having kernel users of sockets that may corrupt task_frag due > to reclaim set sk_use_task_frag = false. Preemptively correcting this > situation for users that still set sk_allocation allows them to convert to > memalloc_nofs_save/restore without the same unexpected corruptions that are > sure to follow, unlikely to show up in testing, and difficult to bisect. > > CC: Philipp Reisner <philipp.reisner@xxxxxxxxxx> > CC: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx> > CC: "Christoph Böhmwalder" <christoph.boehmwalder@xxxxxxxxxx> > CC: Jens Axboe <axboe@xxxxxxxxx> > CC: Josef Bacik <josef@xxxxxxxxxxxxxx> > CC: Keith Busch <kbusch@xxxxxxxxxx> > CC: Christoph Hellwig <hch@xxxxxx> > CC: Sagi Grimberg <sagi@xxxxxxxxxxx> > CC: Lee Duncan <lduncan@xxxxxxxx> > CC: Chris Leech <cleech@xxxxxxxxxx> > CC: Mike Christie <michael.christie@xxxxxxxxxx> > CC: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxx> > CC: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx> > CC: Valentina Manea <valentina.manea.m@xxxxxxxxx> > CC: Shuah Khan <shuah@xxxxxxxxxx> > CC: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > CC: David Howells <dhowells@xxxxxxxxxx> > CC: Marc Dionne <marc.dionne@xxxxxxxxxxxx> > CC: Steve French <sfrench@xxxxxxxxx> > CC: Christine Caulfield <ccaulfie@xxxxxxxxxx> > CC: David Teigland <teigland@xxxxxxxxxx> > CC: Mark Fasheh <mark@xxxxxxxxxx> > CC: Joel Becker <jlbec@xxxxxxxxxxxx> > CC: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> > CC: Eric Van Hensbergen <ericvh@xxxxxxxxx> > CC: Latchesar Ionkov <lucho@xxxxxxxxxx> > CC: Dominique Martinet <asmadeus@xxxxxxxxxxxxx> > CC: "David S. Miller" <davem@xxxxxxxxxxxxx> > CC: Eric Dumazet <edumazet@xxxxxxxxxx> > CC: Jakub Kicinski <kuba@xxxxxxxxxx> > CC: Paolo Abeni <pabeni@xxxxxxxxxx> > CC: Ilya Dryomov <idryomov@xxxxxxxxx> > CC: Xiubo Li <xiubli@xxxxxxxxxx> > CC: Chuck Lever <chuck.lever@xxxxxxxxxx> > CC: Jeff Layton <jlayton@xxxxxxxxxx> > CC: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> > CC: Anna Schumaker <anna@xxxxxxxxxx> > CC: drbd-dev@xxxxxxxxxxxxxxxx > CC: linux-block@xxxxxxxxxxxxxxx > CC: linux-kernel@xxxxxxxxxxxxxxx > CC: nbd@xxxxxxxxxxxxxxxx > CC: linux-nvme@xxxxxxxxxxxxxxxxxxx > CC: open-iscsi@xxxxxxxxxxxxxxxx > CC: linux-scsi@xxxxxxxxxxxxxxx > CC: linux-usb@xxxxxxxxxxxxxxx > CC: linux-afs@xxxxxxxxxxxxxxxxxxx > CC: linux-cifs@xxxxxxxxxxxxxxx > CC: samba-technical@xxxxxxxxxxxxxxx > CC: cluster-devel@xxxxxxxxxx > CC: ocfs2-devel@xxxxxxxxxxxxxx > CC: v9fs-developer@xxxxxxxxxxxxxxxxxxxxx > CC: netdev@xxxxxxxxxxxxxxx > CC: ceph-devel@xxxxxxxxxxxxxxx > CC: linux-nfs@xxxxxxxxxxxxxxx > > Suggested-by: Guillaume Nault <gnault@xxxxxxxxxx> > Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx> I think this is the most feasible way out of the existing issue, and I think this patchset should go via the networking tree, targeting the Linux 6.2. If someone has disagreement with the above, please speak! Thanks, Paolo
