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. #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); > Modules linked in: > CPU: 0 PID: 5091 Comm: syz-executor374 Not tainted 6.9.0-rc7-next-20240506-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 > RIP: 0010:__mod_memcg_lruvec_state+0x18c/0x430 mm/memcontrol.c:999 > Code: ad 35 94 0d 00 0f 85 a4 01 00 00 c6 05 a0 35 94 0d 01 90 48 c7 c7 80 53 d7 8b 48 c7 c6 54 27 b8 8d 44 89 fa e8 55 f1 54 ff 90 <0f> 0b 90 90 e9 7c 01 00 00 4c 8d 7c 24 60 4c 89 fb 48 c1 eb 03 42 > RSP: 0018:ffffc9000338f1e0 EFLAGS: 00010246 > RAX: 38a0635190e19e00 RBX: ffffffff8fad3cb9 RCX: ffff8880221f0000 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: ffffc9000338f2c0 R08: ffffffff815846c2 R09: fffffbfff1c3995c > R10: dffffc0000000000 R11: fffffbfff1c3995c R12: 0000000000000200 > R13: dffffc0000000000 R14: 1ffff92000671e40 R15: 0000000000000019 > FS: 00005555900be380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000000000061cca0 CR3: 0000000075f1c000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > __mod_lruvec_state mm/memcontrol.c:1055 [inline] > __lruvec_stat_mod_folio+0x1a4/0x300 mm/memcontrol.c:1075 > __folio_add_file_rmap mm/rmap.c:1444 [inline] > folio_add_file_rmap_pmd+0x29c/0x700 mm/rmap.c:1485 > do_set_pmd+0x767/0xc40 mm/memory.c:4650 > set_huge_pmd+0x28a/0x710 mm/khugepaged.c:1452 > collapse_pte_mapped_thp+0x5c7/0x10b0 mm/khugepaged.c:1655 > madvise_collapse+0x661/0xcc0 mm/khugepaged.c:2762 > madvise_vma_behavior mm/madvise.c:1094 [inline] > madvise_walk_vmas mm/madvise.c:1268 [inline] > do_madvise+0xc5f/0x44d0 mm/madvise.c:1464 > __do_sys_madvise mm/madvise.c:1481 [inline] > __se_sys_madvise mm/madvise.c:1479 [inline] > __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1479 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f1421be72a9 > Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fffb7f38b78 EFLAGS: 00000246 ORIG_RAX: 000000000000001c > RAX: ffffffffffffffda RBX: 00007fffb7f38d58 RCX: 00007f1421be72a9 > RDX: 0000000000000019 RSI: 0000000000800018 RDI: 0000000020000000 > RBP: 00007f1421c5a610 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 > R13: 00007fffb7f38d48 R14: 0000000000000001 R15: 0000000000000001 > </TASK> > > > --- > If you want syzbot to run the reproducer, reply with: > #syz test: git://repo/address.git branch-or-commit-hash > If you attach or paste a git patch, syzbot will apply it before testing.
