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Tue, 20 May 2025 10:23:43 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B3419201CB; Tue, 20 May 2025 10:23:43 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1F63D201CA; Tue, 20 May 2025 10:23:43 +0000 (GMT) Received: from li-1de7cd4c-3205-11b2-a85c-d27f97db1fe1.ibm.com (unknown [9.111.10.158]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTPS; Tue, 20 May 2025 10:23:43 +0000 (GMT) From: "Marc Hartmayer" To: Johannes Weiner , Zi Yan Cc: Lorenzo Stoakes , Andy Shevchenko , Baolin Wang , linux-mm@kvack.org, linux-s390@vger.kernel.org, Heiko Carstens Subject: Re: page type is 0, migratetype passed is 2 (nr=256) In-Reply-To: <20250512171429.GB615800@cmpxchg.org> References: <87wmalyktd.fsf@linux.ibm.com> <1fc8eb08-7e34-4b16-a08f-c81a531ec3fb@lucifer.local> <20250512171429.GB615800@cmpxchg.org> Date: Tue, 20 May 2025 12:23:42 +0200 Message-ID: <87zff7r369.fsf@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; 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The pageblock is supposed to have >> MIGRATE_RECLAIMABLE(2) before the movement. > > The weird thing is that the warning is from expand(), when the broken > up chunks are put *back*. Marc, can you confirm that this is the only > warning in dmesg, and there aren't any before this one? Yep, I=E2=80=99ve just checked, it was the first warning and `panic_on_warn= ` is set to 1. I managed to reproduce a similar crash using 6.15.0-rc7 (this time THP seems to be involved): =E2=80=A6 root@qemus390x:~# [ 40.442403] ------------[ cut here ]------------ [ 40.442471] page type is 0, passed migratetype is 1 (nr=3D256) [ 40.442525] WARNING: CPU: 0 PID: 350 at mm/page_alloc.c:669 expand (mm= /page_alloc.c:669 (discriminator 2) mm/page_alloc.c:1572 (discriminator 2)) [ 40.442558] Modules linked in: pkey_pckmo(E) pkey(E) diag288_wdt(E) wa= tchdog(E) s390_trng(E) virtio_console(E) rng_core(E) vmw_vsock_virtio_trans= port(E) vmw_vsock_virtio_transport_common(E) vsock(E) ghash_s390(E) prng(E)= aes_s390(E) des_s390(E) libdes(E) sha3_512_s390(E) sha3_256_s390(E) sha512= _s390(E) sha256_s390(E) sha1_s390(E) sha_common(E) vfio_ccw(E) mdev(E) vfio= _iommu_type1(E) vfio(E) sch_fq_codel(E) drm(E) i2c_core(E) drm_panel_orient= ation_quirks(E) nfnetlink(E) autofs4(E) [ 40.442651] Unloaded tainted modules: hmac_s390(E):1 [ 40.442677] CPU: 0 UID: 0 PID: 350 Comm: mempig_verify Tainted: G = E 6.15.0-rc7-11557-ga01c92c55b53 #1 PREEMPT [ 40.442683] Tainted: [E]=3DUNSIGNED_MODULE [ 40.442687] Hardware name: IBM 3931 A01 701 (KVM/Linux) [ 40.442692] Krnl PSW : 0404d00180000000 000002ff929af40c expand (mm/pa= ge_alloc.c:669 (discriminator 10) mm/page_alloc.c:1572 (discriminator 10)) [ 40.442696] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 P= M:0 RI:0 EA:3 [ 40.442699] Krnl GPRS: 000002ff80000004 0000000000000005 0000000000000= 030 0000000000000000 [ 40.442701] 0000000000000005 0000027f80000005 0000000000000= 100 0000000000000008 [ 40.442703] 000002ff93f99290 000001f63a415900 0000027500000= 008 00000275829f4000 [ 40.442704] 0000000000000000 0000000000000008 000002ff929af= 408 0000027f928c36f8 [ 40.442722] Krnl Code: 000002ff929af3fc: c02000883f4b larl %r2,000002ff9= 3ab7292 Code starting with the faulting instruction =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D [ 40.442722] 000002ff929af402: c0e5ffe7bd17 brasl %= r14,000002ff926a6e30 [ 40.442722] #000002ff929af408: af000000 mc 0= ,0 [ 40.442722] >000002ff929af40c: a7f4ff49 brc 1= 5,000002ff929af29e [ 40.442722] 000002ff929af410: b904002b lgr %= r2,%r11 [ 40.442722] 000002ff929af414: c03000881980 larl %= r3,000002ff93ab2714 [ 40.442722] 000002ff929af41a: c0e5fffdd883 brasl %= r14,000002ff9296a520 [ 40.442722] 000002ff929af420: af000000 mc 0= ,0 [ 40.442736] Call Trace: [ 40.442738] expand (mm/page_alloc.c:669 (discriminator 10) mm/page_all= oc.c:1572 (discriminator 10)) [ 40.442741] expand (mm/page_alloc.c:669 (discriminator 2) mm/page_allo= c.c:1572 (discriminator 2)) [ 40.442743] rmqueue_bulk (mm/page_alloc.c:1587 mm/page_alloc.c:1758 mm= /page_alloc.c:2311 mm/page_alloc.c:2364) [ 40.442745] __rmqueue_pcplist (mm/page_alloc.c:3086) [ 40.442748] rmqueue.isra.0 (mm/page_alloc.c:3124 mm/page_alloc.c:3155) [ 40.442751] get_page_from_freelist (mm/page_alloc.c:3683) [ 40.442754] __alloc_frozen_pages_noprof (mm/page_alloc.c:4967 (discrim= inator 1)) [ 40.442756] alloc_pages_mpol (mm/mempolicy.c:2290) [ 40.442764] folio_alloc_mpol_noprof (mm/mempolicy.c:2322) [ 40.442766] vma_alloc_folio_noprof (mm/mempolicy.c:2355 (discriminator= 1)) [ 40.442769] vma_alloc_anon_folio_pmd (mm/huge_memory.c:1167 (discrimin= ator 1)) [ 40.442773] __do_huge_pmd_anonymous_page (mm/huge_memory.c:1227 (discr= iminator 1)) [ 40.442775] __handle_mm_fault (mm/memory.c:5862 mm/memory.c:6111) [ 40.442781] handle_mm_fault (mm/memory.c:6321) [ 40.442783] do_exception (arch/s390/mm/fault.c:298) [ 40.442792] __do_pgm_check (arch/s390/kernel/traps.c:345) [ 40.442802] pgm_check_handler (arch/s390/kernel/entry.S:334) [ 40.442805] Last Breaking-Event-Address: [ 40.442806] __warn_printk (kernel/panic.c:801) [ 40.442818] Kernel panic - not syncing: kernel: panic_on_warn set ... [ 40.442822] CPU: 0 UID: 0 PID: 350 Comm: mempig_verify Tainted: G = E 6.15.0-rc7-11557-ga01c92c55b53 #1 PREEMPT [ 40.442825] Tainted: [E]=3DUNSIGNED_MODULE [ 40.442826] Hardware name: IBM 3931 A01 701 (KVM/Linux) [ 40.442827] Call Trace: [ 40.442828] dump_stack_lvl (lib/dump_stack.c:122) [ 40.442831] panic (kernel/panic.c:372) [ 40.442833] check_panic_on_warn (kernel/panic.c:247) [ 40.442836] __warn (kernel/panic.c:751) [ 40.443057] report_bug (lib/bug.c:176 lib/bug.c:215) [ 40.443064] monitor_event_exception (arch/s390/kernel/traps.c:227 (dis= criminator 1)) [ 40.443067] __do_pgm_check (arch/s390/kernel/traps.c:345) [ 40.443071] pgm_check_handler (arch/s390/kernel/entry.S:334) [ 40.443074] expand (mm/page_alloc.c:669 (discriminator 10) mm/page_all= oc.c:1572 (discriminator 10)) [ 40.443077] expand (mm/page_alloc.c:669 (discriminator 2) mm/page_allo= c.c:1572 (discriminator 2)) [ 40.443080] rmqueue_bulk (mm/page_alloc.c:1587 mm/page_alloc.c:1758 mm= /page_alloc.c:2311 mm/page_alloc.c:2364) [ 40.443087] __rmqueue_pcplist (mm/page_alloc.c:3086) [ 40.443090] rmqueue.isra.0 (mm/page_alloc.c:3124 mm/page_alloc.c:3155) [ 40.443093] get_page_from_freelist (mm/page_alloc.c:3683) [ 40.443097] __alloc_frozen_pages_noprof (mm/page_alloc.c:4967 (discrim= inator 1)) [ 40.443100] alloc_pages_mpol (mm/mempolicy.c:2290) [ 40.443104] folio_alloc_mpol_noprof (mm/mempolicy.c:2322) [ 40.443110] vma_alloc_folio_noprof (mm/mempolicy.c:2355 (discriminator= 1)) [ 40.443114] vma_alloc_anon_folio_pmd (mm/huge_memory.c:1167 (discrimin= ator 1)) [ 40.443117] __do_huge_pmd_anonymous_page (mm/huge_memory.c:1227 (discr= iminator 1)) [ 40.443120] __handle_mm_fault (mm/memory.c:5862 mm/memory.c:6111) [ 40.443123] handle_mm_fault (mm/memory.c:6321) [ 40.443126] do_exception (arch/s390/mm/fault.c:298) [ 40.443129] __do_pgm_check (arch/s390/kernel/traps.c:345) [ 40.443132] pgm_check_handler (arch/s390/kernel/entry.S:334) This time, the setup is even simpler: 1. Start a 2GB QEMU/KVM guest 2. Now run some memory stress test I run this test in a loop (with starting/shutting down the VM) and after many iterations, the bug occurs. [=E2=80=A6snip=E2=80=A6]