On Mon, May 06, 2024 at 02:11:57PM +0000, Yosry Ahmed wrote: > On Mon, May 06, 2024 at 06:03:29AM -0700, syzbot wrote: > > syzbot has found a reproducer for the following issue on: > > > > HEAD commit: 2b84edefcad1 Add linux-next specific files for 20240506 > > git tree: linux-next > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1164931f180000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=b499929e4aaba1af > > dashboard link: https://syzkaller.appspot.com/bug?extid=9319a4268a640e26b72b > > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=123d5d1f180000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16527450980000 > > > > Downloadable assets: > > disk image: https://storage.googleapis.com/syzbot-assets/6a22cf95ee14/disk-2b84edef.raw.xz > > vmlinux: https://storage.googleapis.com/syzbot-assets/f5c45b515282/vmlinux-2b84edef.xz > > kernel image: https://storage.googleapis.com/syzbot-assets/9bf98258a662/bzImage-2b84edef.xz > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+9319a4268a640e26b72b@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > ------------[ cut here ]------------ > > __mod_memcg_lruvec_state: missing stat item 25 > > WARNING: CPU: 0 PID: 5091 at mm/memcontrol.c:999 __mod_memcg_lruvec_state+0x18c/0x430 mm/memcontrol.c:999 > > This doesn't seem to be the same issue as the original one syzbot > reported. It's the same function but a different warning. I am not sure > how to tell syzbot that. > > Anyway, this warning is the one newly introduced by Shakeel. It is > firing because NR_SHMEM_PMDMAPPED and/or NR_FILE_PMDMAPPED are being > updated using __lruvec_stat_mod_folio(), which also updates the memcg > stats. However, these stats are not exported per-memcg. > > I think the following should fix it. > Hey Yosry, can you please post your patch with the signoff? The patch looks good and you can put my ack on it. > #syz test > > diff --git a/mm/rmap.c b/mm/rmap.c > index 12be4241474ab..d3a26ea4dbae2 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -1441,7 +1441,7 @@ static __always_inline void __folio_add_file_rmap(struct folio *folio, > > nr = __folio_add_rmap(folio, page, nr_pages, level, &nr_pmdmapped); > if (nr_pmdmapped) > - __lruvec_stat_mod_folio(folio, folio_test_swapbacked(folio) ? > + __mod_node_page_state(folio, folio_test_swapbacked(folio) ? > NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, nr_pmdmapped); > if (nr) > __lruvec_stat_mod_folio(folio, NR_FILE_MAPPED, nr); >
