From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f199.google.com (mail-oi1-f199.google.com [209.85.167.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B7FE3932F2 for ; Mon, 20 Apr 2026 10:07:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776679637; cv=none; b=LLnam+iQBUNtVwUeAqW/EF/D8CP83KaOpVVu/AlAnOlNf+ftV2J0omQuuYKQpoLHvUAwj+SP38k8JkBGKdwYX6vRq+PaPj9Dpm1/YtuoUo6+TEwdsV3nC5xguewvh2lLOM4dj5U4cKJYdWYOQMRrLFSQ2nmum6gDuohTsGHDu6A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776679637; c=relaxed/simple; bh=c8ZPc6ipTEV3sd5HyCNm62LqmfhuNl4ekASTJGzWlnw=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To:Cc: Content-Type; b=jSJulJ+vW/d2uZn0luAztWCtC/HU9Meeo9t29DQglaz2Z3vKuchAD5jq4Ki9jUXXduXszjzS5+InAQeTFnjvOneaSntEOZIG7yNhFtQSxwzYqXMTcr17nqBcMjvslIDLkF2rieoloxkE6oEv8KY7c7YnaTCZqHT2TKpVEJCs55E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.167.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oi1-f199.google.com with SMTP id 5614622812f47-4723af8974fso2138032b6e.3 for ; Mon, 20 Apr 2026 03:07:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776679634; x=1777284434; h=content-transfer-encoding:cc:to:from:subject:message-id:in-reply-to :date:mime-version:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=DjpMJLyJHTl1mKAWHq8djAY85Ht0d1iy4vRhA/ss9Y4=; b=C4e1oVky4KTKDydSPdGcXJuLE6CGVgisbz2RoCiW1nfDIbSgKWY3y7VLp2hr+a9UPp 18JgO0FFO0X3GKGDknJ1u+TjNHQGoid9qX5Km93H6CfhuH1l+PZryUeFiZ0MkU0WnPjX PyasQ1egtgOjBYNnwmxyFy23LF1ULTrBPvtAmtFN+gW0kWYGNYYjGFTY0nLN2mmWupRu rEScG08U8/e1l4Mi0aH3tJNoXWl5gb/gTPlurNwXhExC0fmTpgFFy3gkyHMrFinY+fjM WadHYZHNxNkVUGpyw4NQczMVqGjKAexzFVOemHtXyRHZfoNiC/zco4W3WX202V2cxDQz 2R1g== X-Forwarded-Encrypted: i=1; AFNElJ9Fqqq/RrbPUPRTvHQpQvqVGJ5JlYVENRVcRg467P9C6kRFKpDfogy8iPVAkwWkntcPX6OfVzh2aYUG0e4=@vger.kernel.org X-Gm-Message-State: AOJu0YwZh3ECKNOXSSiIGhbOzgvhOxtZadJ2VeCdVASrFXvFCTf6v3Ea F/Dqmmrz+lfRICrFMDsOMEyhwX5FdWJLiUnv1GlAe5FXKn2a6MXfss8tWGEnZUapDNmvHrHB/z4 x2wXDUmKH04gmpKyIgoMa3dQ3Ja323dAtIedjygYQ4B2wVrqNBBW/lkOxmiA= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4c06:b0:694:8f3a:3f41 with SMTP id 006d021491bc7-6948f3a4683mr251846eaf.41.1776679634403; Mon, 20 Apr 2026 03:07:14 -0700 (PDT) Date: Mon, 20 Apr 2026 03:07:14 -0700 In-Reply-To: X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69e5fad2.a00a0220.9259.0002.GAE@google.com> Subject: [syzbot ci] Re: mm: improve folio refcount scalability From: syzbot ci To: akpm@linux-foundation.org, apopple@nvidia.com, artem.kuzin@huawei.com, baolin.wang@linux.alibaba.com, david@kernel.org, gladyshev.ilya1@h-partners.com, gorbunov.ivan@h-partners.com, harry.yoo@oracle.com, kirill@shutemov.name, liam.howlett@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, mhocko@suse.com, muchun.song@linux.dev, rppt@kernel.org, surenb@google.com, torvalds@linuxfoundation.org, vbabka@suse.cz, willy@infradead.org, yuzhao@google.com, ziy@nvidia.com Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable syzbot ci has tested the following series [v2] mm: improve folio refcount scalability https://lore.kernel.org/all/cover.1776350895.git.gorbunov.ivan@h-partners.c= om * [PATCH v2 1/2] mm: drop page refcount zero state semantics * [PATCH v2 2/2] mm: implement page refcount locking via dedicated bit and found the following issue: kernel BUG in get_page_bootmem Full report is available here: https://ci.syzbot.org/series/eb14b73a-c461-4be5-b5af-91864e939f4c *** kernel BUG in get_page_bootmem tree: mm-new URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm= .git base: f4279f87cd6c82ebdaccdc56f38e7b80ca7fcc03 arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp= 1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/60ced5f4-8c33-43ea-a4ee-92d9b2b8f94= 9/config ACPI: HPET id: 0x8086a201 base: 0xfed00000 CPU topo: Max. logical packages: 2 CPU topo: Max. logical nodes: 1 CPU topo: Num. nodes per package: 1 CPU topo: Max. logical dies: 2 CPU topo: Max. dies per package: 1 CPU topo: Max. threads per core: 1 CPU topo: Num. cores per package: 1 CPU topo: Num. threads per package: 1 CPU topo: Allowing 2 present CPUs plus 0 hotplug CPUs kvm-guest: APIC: eoi() replaced with kvm_guest_apic_eoi_write() PM: hibernation: Registered nosave memory: [mem 0x00000000-0x00000fff] PM: hibernation: Registered nosave memory: [mem 0x0009f000-0x000fffff] PM: hibernation: Registered nosave memory: [mem 0x7ffdf000-0xffffffff] [gap 0xc0000000-0xfed1bfff] available for PCI devices Booting paravirtualized kernel on KVM clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_= idle_ns: 19112604462750000 ns Zone ranges: DMA [mem 0x0000000000001000-0x0000000000ffffff] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] Normal [mem 0x0000000100000000-0x000000023fffffff] Device empty Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000000001000-0x000000000009efff] node 0: [mem 0x0000000000100000-0x000000007ffdefff] node 0: [mem 0x0000000100000000-0x0000000160000fff] node 1: [mem 0x0000000160001000-0x000000023fffffff] Initmem setup node 0 [mem 0x0000000000001000-0x0000000160000fff] Initmem setup node 1 [mem 0x0000000160001000-0x000000023fffffff] On node 0, zone DMA: 1 pages in unavailable ranges On node 0, zone DMA: 97 pages in unavailable ranges On node 0, zone Normal: 33 pages in unavailable ranges setup_percpu: NR_CPUS:8 nr_cpumask_bits:2 nr_cpu_ids:2 nr_node_ids:2 percpu: Embedded 71 pages/cpu s250120 r8192 d32504 u2097152 kvm-guest: PV spinlocks disabled, no host support Kernel command line: earlyprintk=3Dserial net.ifnames=3D0 sysctl.kernel.hun= g_task_all_cpu_backtrace=3D1 ima_policy=3Dtcb nf-conntrack-ftp.ports=3D2000= 0 nf-conntrack-tftp.ports=3D20000 nf-conntrack-sip.ports=3D20000 nf-conntra= ck-irc.ports=3D20000 nf-conntrack-sane.ports=3D20000 binder.debug_mask=3D0 = rcupdate.rcu_expedited=3D1 rcupdate.rcu_cpu_stall_cputime=3D1 no_hash_point= ers page_owner=3Don sysctl.vm.nr_hugepages=3D4 sysctl.vm.nr_overcommit_huge= pages=3D4 secretmem.enable=3D1 sysctl.max_rcu_stall_to_panic=3D1 msr.allow_= writes=3Doff coredump_filter=3D0xffff root=3D/dev/sda console=3DttyS0 vsysc= all=3Dnative numa=3Dfake=3D2 kvm-intel.nested=3D1 spec_store_bypass_disable= =3Dprctl nopcid vivid.n_devs=3D64 vivid.multiplanar=3D1,2,1,2,1,2,1,2,1,2,1= ,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,= 1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2 netrom.nr_ndevs=3D32 rose.rose_ndevs=3D32 s= mp.csd_lock_timeout=3D100000 watchdog_thresh=3D55 workqueue.watchdog_thresh= =3D140 sysctl.net.core.netdev_unregister_timeout_secs=3D140 dummy_hcd.num= =3D32 max_loop=3D32 nbds_max=3D32 \ Kernel command line: comedi.comedi_num_legacy_minors=3D4 panic_on_warn=3D1 = root=3D/dev/sda console=3DttyS0 root=3D/dev/sda1 Unknown kernel command line parameters "nbds_max=3D32", will be passed to u= ser space. printk: log buffer data + meta data: 262144 + 917504 =3D 1179648 bytes software IO TLB: area num 2. Fallback order for Node 0: 0 1=20 Fallback order for Node 1: 1 0=20 Built 2 zonelists, mobility grouping on. Total pages: 1834877 Policy zone: Normal mem auto-init: stack:all(zero), heap alloc:on, heap free:off stackdepot: allocating hash table via alloc_large_system_hash stackdepot hash table entries: 1048576 (order: 12, 16777216 bytes, linear) stackdepot: allocating space for 8192 stack pools via memblock ------------[ cut here ]------------ kernel BUG at ./include/linux/page_ref.h:171! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted syzkaller #0 PREEMPT(undef)= =20 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16= .2-1 04/01/2014 RIP: 0010:get_page_bootmem+0x188/0x190 Code: 86 ff 90 0f 0b e8 98 52 86 ff 90 0f 0b e8 90 52 86 ff 48 89 df 48 c7 = c6 00 e4 dd 8b e8 51 d7 e8 fe 90 0f 0b e8 79 52 86 ff 90 <0f> 0b 66 0f 1f 4= 4 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 0000:ffffffff8e407e50 EFLAGS: 00010093 RAX: ffffffff823f42b7 RBX: ffffea00057ffec0 RCX: ffffffff8e494ec0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffffea00057ffef7 R09: 1ffffd4000afffde R10: dffffc0000000000 R11: fffff94000afffdf R12: dffffc0000000000 R13: 0000000000000000 R14: ffffea00057ffef4 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff88818de62000(0000) knlGS:000000000000000= 0 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88823ffff000 CR3: 000000000e54c000 CR4: 00000000000000b0 Call Trace: register_page_bootmem_info_node+0x88/0x410 register_page_bootmem_info+0x77/0xc0 mem_init+0x5a/0xb0 mm_core_init+0x79/0xb0 start_kernel+0x15a/0x3d0 x86_64_start_reservations+0x24/0x30 x86_64_start_kernel+0x143/0x1c0 common_startup_64+0x13e/0x147 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:get_page_bootmem+0x188/0x190 Code: 86 ff 90 0f 0b e8 98 52 86 ff 90 0f 0b e8 90 52 86 ff 48 89 df 48 c7 = c6 00 e4 dd 8b e8 51 d7 e8 fe 90 0f 0b e8 79 52 86 ff 90 <0f> 0b 66 0f 1f 4= 4 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 0000:ffffffff8e407e50 EFLAGS: 00010093 RAX: ffffffff823f42b7 RBX: ffffea00057ffec0 RCX: ffffffff8e494ec0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffffea00057ffef7 R09: 1ffffd4000afffde R10: dffffc0000000000 R11: fffff94000afffdf R12: dffffc0000000000 R13: 0000000000000000 R14: ffffea00057ffef4 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff88818de62000(0000) knlGS:000000000000000= 0 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88823ffff000 CR3: 000000000e54c000 CR4: 00000000000000b0 *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com. To test a patch for this bug, please reply with `#syz test` (should be on a separate line). The patch should be attached to the email. Note: arguments like custom git repos and branches are not supported.