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AJvYcCWDrEvSJdGOfQL6ikWZhpt26B/JRcMoKu/rBMyiTNU3m0kFr175n0vFwg9DLuN5Zo2VErJBGMEP47Kd7aY=@vger.kernel.org X-Gm-Message-State: AOJu0YyA2stTvsMYOQbd5RJxx0A9kuKWDI6jExX9fva3GIkQX2sVJ5xK P2EeQ5nOjL5dOHBvZeqOCdySKs7BxhDm4aiQQmw0encYoTJOOS7p2fMKSFO4v6lz25IYGCAR3Tf 6VzMK20jpAH6ABuI9Mz1g0Au5jYWmXZYSyhso4+DsEkfpeioEuXBrAV1jdOE= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:203:b0:67c:3142:b174 with SMTP id 006d021491bc7-6821d53c55fmr11507527eaf.9.1775647973877; Wed, 08 Apr 2026 04:32:53 -0700 (PDT) Date: Wed, 08 Apr 2026 04:32:53 -0700 In-Reply-To: <20260408092441.435133-1-hsalunke@amd.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69d63ce5.a00a0220.468cb.000e.GAE@google.com> Subject: [syzbot ci] Re: mm/page_alloc: use batch page clearing in kernel_init_pages() From: syzbot ci To: akpm@linux-foundation.org, ankur.a.arora@oracle.com, bharata@amd.com, hannes@cmpxchg.org, hsalunke@amd.com, jackmanb@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, rkodsara@amd.com, shivankg@amd.com, surenb@google.com, vbabka@kernel.org, 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 [v1] mm/page_alloc: use batch page clearing in kernel_init_pages() https://lore.kernel.org/all/20260408092441.435133-1-hsalunke@amd.com * [PATCH] mm/page_alloc: use batch page clearing in kernel_init_pages() and found the following issue: WARNING in preempt_model_full Full report is available here: https://ci.syzbot.org/series/be6c0534-641b-42aa-8b73-ab8f592ec267 *** WARNING in preempt_model_full tree: mm-new URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm= .git base: 0d90551ea699ef3d1a85cd7a1a7e21e8d4f04db2 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/22cbd293-31c6-46b9-b8d4-2ff590ce406= b/config 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 ]------------ preempt_dynamic_mode =3D=3D preempt_dynamic_undefined WARNING: kernel/sched/core.c:7743 at preempt_model_full+0x1e/0x30, CPU#0: s= wapper/0 Modules linked in: 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:preempt_model_full+0x1e/0x30 Code: 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 83 3d 35 d9 cb 0c ff = 74 10 83 3d 2c d9 cb 0c 02 0f 94 c0 2e e9 93 fa 19 0a 90 <0f> 0b 90 eb ea 6= 6 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 RSP: 0000:ffffffff8e407a78 EFLAGS: 00010046 RAX: 1ffffffff1c359d9 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffea0004000000 RBP: 0000000000040100 R08: ffffffff8221aafb R09: 0000000000000000 R10: ffffed1020000000 R11: ffffed1024206961 R12: 0000000000000001 R13: 0000000000000001 R14: ffff888100000000 R15: dffffc0000000000 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: kernel_init_pages+0x6d/0xe0 post_alloc_hook+0xae/0x1e0 get_page_from_freelist+0x24ba/0x2540 __alloc_frozen_pages_noprof+0x18d/0x380 alloc_pages_mpol+0x235/0x490 alloc_pages_noprof+0xac/0x2a0 __pud_alloc+0x3a/0x460 preallocate_vmalloc_pages+0x386/0x3d0 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 *** 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.