Hello Krister, > -----Original Message----- > From: Krister Johansen <kjlx@xxxxxxxxxxxxxxxxxx> > Sent: Friday, November 10, 2023 2:10 AM > To: Borah, Chaitanya Kumar <chaitanya.kumar.borah@xxxxxxxxx> > Cc: kjlx@xxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Kurmi, Suresh > Kumar <suresh.kumar.kurmi@xxxxxxxxx>; Saarinen, Jani > <jani.saarinen@xxxxxxxxx>; Miklos Szeredi <mszeredi@xxxxxxxxxx> > Subject: Re: Regression on linux-next (next-20231107) > > Hi Chaitanya, > > On Thu, Nov 09, 2023 at 05:00:09PM +0000, Borah, Chaitanya Kumar wrote: > > Hello Krister, > > > > Hope you are doing well. I am Chaitanya from the linux graphics team in > Intel. > > > > This mail is regarding a regression we are seeing in our CI runs[1] for some > machines (dg2 and adl-p) on linux-next repository. > > > > Since the version next-20231107 [2], we are seeing the following error > > ``````````````````````````````````````````````````````````````````````````````` > > <4>[ 32.015910] stack segment: 0000 [#1] PREEMPT SMP NOPTI > > <4>[ 32.021048] CPU: 15 PID: 766 Comm: fusermount Not tainted 6.6.0- > next-20231107-next-20231107-g5cd631a52568+ #1 > > <4>[ 32.031135] Hardware name: Intel Corporation Raptor Lake Client > Platform/RPL-S ADP-S DDR5 UDIMM CRB, BIOS > RPLSFWI1.R00.4221.A00.2305271351 05/27/2023 > > <4>[ 32.044657] RIP: 0010:fuse_evict_inode+0x61/0x150 [fuse] > > `````````````````````````````````````````````````````````````````````` > > ``````````` > > > > Details log can be found in [3]. > > > > After bisecting the tree, the following patch [4] seems to be the > > first "bad" commit > > > > > > `````````````````````````````````````````````````````````````````````` > > ``````````````````````````````````` > > 513dfacefd712bcbfab64e1a9c9c3e0d51c2dca5 is the first bad commit > > commit 513dfacefd712bcbfab64e1a9c9c3e0d51c2dca5 > > Author: Krister Johansen kjlx@xxxxxxxxxxxxxxxxxx > > Date: Fri Nov 3 10:39:47 2023 -0700 > > > > fuse: share lookup state between submount and its parent > > > > Fuse submounts do not perform a lookup for the nodeid that they inherit > > from their parent. Instead, the code decrements the nlookup on the > > submount's fuse_inode when it is instantiated, and no forget is > > performed when a submount root is evicted. > > > > Trouble arises when the submount's parent is evicted despite the > > submount itself being in use. In this author's case, the submount was > > in a container and deatched from the initial mount namespace via a > > MNT_DEATCH operation. When memory pressure triggered the shrinker, > the > > inode from the parent was evicted, which triggered enough forgets to > > render the submount's nodeid invalid. > > > > Since submounts should still function, even if their parent goes away, > > solve this problem by sharing refcounted state between the parent and > > its submount. When all of the references on this shared state reach > > zero, it's safe to forget the final lookup of the fuse nodeid. > > > > > > `````````````````````````````````````````````````````````````````````` > > ``````````````````````````````````` > > > > We also verified that if we revert the patch the issue is not seen. > > > > Could you please check why the patch causes this regression and provide a > fix if necessary? > > Apologies for the inconvenience. I've reproduced the problem, tested a fix, > and am in the process of preparing patches to send to Miklos. I'll cc the > people on this e-mail in that thread. > > > [3] > > http://gfx-ci.igk.intel.com/tree/linux-next/next-20231109/bat-dg2-14/b > > oot0.txt > > This link didn't resolve in DNS when I tried to access it. I needed to use intel- > gfx-ci.01.org as the hostname instead. > My bad. I realized it too late. Hope you found the logs. If not here they are. https://intel-gfx-ci.01.org/tree/linux-next/next-20231109/bat-dg2-14/boot0.txt Regards Chaitanya > Thanks, > > -K
