From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Mike Rapoport <rppt@kernel.org>
Cc: linux-mm@kvack.org, Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH] mm: Fix memblock_free_late() when using deferred struct page
Date: Tue, 10 Feb 2026 19:34:15 +1100 [thread overview]
Message-ID: <0344bfbeb017cafc0f7bd4433eeacd9bc802d9c9.camel@kernel.crashing.org> (raw)
In-Reply-To: <5a44609fe992624573a3ca0a293888bd623e2a06.camel@kernel.crashing.org>
On Tue, 2026-02-10 at 17:17 +1100, Benjamin Herrenschmidt wrote:
>
> So ... that was a backport to 6.12.68 and my original patch is
> crashing
> the same way ! (it was working last week interestingly enough,
> something else got backported that gets in the way maybe ?).
>
> I'm going to have to go back to digging :-(
>
> I suspect the pages aren't reserved. I swear this was working :-)
So I rebuilt with a bit of extra debug prints, CONFIG_DEBUG_VM on, and
memblock=debug ... it's not hitting the reserved check, but it's also
not crashing the same way (still 6.12, I'll play with upstream again
later):
.../...
[ 0.045633] Freeing SMP alternatives memory: 36K
[ 0.045633] pid_max: default: 32768 minimum: 301
[ 0.045633] memblock_free_late: [0x000000003d36b000-0x000000003d37bfff] efi_free_boot_services+0x11f/0x2e0
[ 0.045633] memblock_free_late: [0x000000003b336000-0x000000003d36afff] efi_free_boot_services+0x11f/0x2e0
[ 0.045633] memblock_free_late: [0x000000003b317000-0x000000003b335fff] efi_free_boot_services+0x11f/0x2e0
[ 0.045633] memblock_free_late: [0x000000003b2f7000-0x000000003b316fff] efi_free_boot_services+0x11f/0x2e0
[ 0.045633] memblock_free_late: [0x000000003b000000-0x000000003b1fffff] efi_free_boot_services+0x11f/0x2e0
[ 0.045633] memblock_free_late: [0x00000000393de000-0x00000000393defff] efi_free_boot_services+0x11f/0x2e0
[ 0.045633] memblock_free_late: [0x0000000038e73000-0x00000000390cdfff] efi_free_boot_services+0x11f/0x2e0
[ 0.045633] LSM: initializing lsm=lockdown,capability,landlock,yama,safesetid,selinux,bpf,ima
[ 0.045633] landlock: Up and running.
[ 0.045633] Yama: becoming mindful.
[ 0.045633] SELinux: Initializing.
[ 0.045633] LSM support for eBPF active
[ 0.045633] Mount-cache hash table entries: 2048 (order: 2, 16384 bytes, linear)
[ 0.045633] Mountpoint-cache hash table entries: 2048 (order: 2, 16384 bytes, linear)
[ 0.045633] smpboot: CPU0: Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz (family: 0x6, model: 0x55, stepping: 0x7)
[ 0.045633] Performance Events: unsupported p6 CPU model 85 no PMU driver, software events only.
[ 0.045633] signal: max sigframe size: 3632
[ 0.045633] rcu: Hierarchical SRCU implementation.
[ 0.045633] rcu: Max phase no-delay instances is 1000.
[ 0.045633] Timer migration: 1 hierarchy levels; 8 children per group; 1 crossnode level
[ 0.045633] smp: Bringing up secondary CPUs ...
[ 0.045633] smpboot: x86: Booting SMP configuration:
[ 0.045633] .... node #0, CPUs: #1
[ 0.045633] MDS CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html for more details.
[ 0.045633] MMIO Stale Data CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/processor_mmio_stale_data.html for more details.
[ 0.045633] smp: Brought up 1 node, 2 CPUs
[ 0.045633] smpboot: Total of 2 processors activated (9999.97 BogoMIPS)
[ 0.045633] node 0 deferred pages initialised in 0ms
[ 0.045633] Memory: 900460K/999468K available (16384K kernel code, 9440K rwdata, 11364K rodata, 3740K init, 6440K bss, 94600K reserved, 0K cma-reserved)
[ 0.045633] devtmpfs: initialized
[ 0.045633] x86/mm: Memory block size: 128MB
[ 0.045633] ------------[ cut here ]------------
[ 0.045633] page type is 1, passed migratetype is 0 (nr=16)
[ 0.045633] WARNING: CPU: 1 PID: 2 at mm/page_alloc.c:721 rmqueue_bulk+0x82e/0x880
[ 0.045633] Modules linked in:
[ 0.045633] CPU: 1 UID: 0 PID: 2 Comm: kthreadd Not tainted 6.12.68-93.123.amzn2023.x86_64 #1
[ 0.045633] Hardware name: Amazon EC2 t3.micro/, BIOS 1.0 10/16/2017
[ 0.045633] RIP: 0010:rmqueue_bulk+0x82e/0x880
[ 0.045633] Code: c6 05 be be 13 02 01 e8 b0 b5 ff ff 44 89 e9 8b 14 24 48 c7 c7 a8 6d 51 8e 48 89 c6 b8 01 00 00 00 d3 e0 89 c1 e8 32 4f d2 ff <0f> 0b 4c 8b 44 24 48 e9 79 fc ff ff 48 c7 c6 e0 77 51 8e 4c 89 e7
[ 0.045633] RSP: 0000:ffffd592c002f898 EFLAGS: 00010086
[ 0.045633] RAX: 0000000000000000 RBX: ffff8e363b2cbc80 RCX: ffffffff8f1f0c68
[ 0.045633] RDX: 0000000000000000 RSI: 00000000fffeffff RDI: 0000000000000001
[ 0.045633] RBP: fffffb9c40e3a408 R08: 0000000000000000 R09: ffffd592c002f740
[ 0.045633] R10: ffffd592c002f738 R11: ffffffff8f370ca8 R12: fffffb9c40e3a400
[ 0.045633] R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000038e90
[ 0.045633] FS: 0000000000000000(0000) GS:ffff8e3639f00000(0000) knlGS:0000000000000000
[ 0.045633] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.045633] CR2: 0000000000000000 CR3: 000000001bc34001 CR4: 00000000007706f0
[ 0.045633] PKRU: 55555554
[ 0.045633] Call Trace:
[ 0.045633] <TASK>
[ 0.045633] __rmqueue_pcplist+0x233/0x2c0
[ 0.045633] rmqueue.constprop.0+0x4b6/0xe80
[ 0.045633] ? _raw_spin_unlock+0xa/0x30
[ 0.045633] ? rmqueue.constprop.0+0x557/0xe80
[ 0.045633] ? _raw_spin_unlock_irqrestore+0xa/0x30
[ 0.045633] get_page_from_freelist+0x16e/0x5f0
[ 0.045633] __alloc_pages_noprof+0x18a/0x350
[ 0.045633] alloc_pages_mpol_noprof+0xf2/0x1e0
[ 0.045633] ? shuffle_freelist+0x126/0x1b0
[ 0.045633] allocate_slab+0x2b3/0x410
[ 0.045633] ___slab_alloc+0x396/0x830
[ 0.045633] ? switch_hrtimer_base+0x8e/0x190
[ 0.045633] ? timerqueue_add+0x9b/0xc0
[ 0.045633] ? dup_task_struct+0x2d/0x1b0
[ 0.045633] ? _raw_spin_unlock_irqrestore+0xa/0x30
[ 0.045633] ? start_dl_timer+0xb0/0x140
[ 0.045633] kmem_cache_alloc_node_noprof+0x271/0x2e0
[ 0.045633] ? dup_task_struct+0x2d/0x1b0
[ 0.045633] dup_task_struct+0x2d/0x1b0
[ 0.045633] copy_process+0x195/0x17e0
[ 0.045633] kernel_clone+0x9a/0x3b0
[ 0.045633] ? psi_task_switch+0x105/0x290
[ 0.045633] kernel_thread+0x6b/0x90
[ 0.045633] ? __pfx_kthread+0x10/0x10
[ 0.045633] kthreadd+0x276/0x2d0
[ 0.045633] ? __pfx_kthreadd+0x10/0x10
[ 0.045633] ret_from_fork+0x30/0x50
[ 0.045633] ? __pfx_kthreadd+0x10/0x10
[ 0.045633] ret_from_fork_asm+0x1a/0x30
[ 0.045633] </TASK>
[ 0.045633] ---[ end trace 0000000000000000 ]---
[ 0.045633] ------------[ cut here ]------------
[ 0.045633] page type is 1, passed migratetype is 0 (nr=8)
[ 0.045633] WARNING: CPU: 1 PID: 2 at mm/page_alloc.c:686 expand+0x1af/0x1e0
[ 0.045633] Modules linked in:
[ 0.045633] CPU: 1 UID: 0 PID: 2 Comm: kthreadd Tainted: G W 6.12.68-93.123.amzn2023.x86_64 #1
[ 0.045633] Tainted: [W]=WARN
[ 0.045633] Hardware name: Amazon EC2 t3.micro/, BIOS 1.0 10/16/2017
[ 0.045633] RIP: 0010:expand+0x1af/0x1e0
[ 0.045633] Code: c6 05 af 06 14 02 01 e8 9f fd ff ff 89 e9 8b 54 24 34 48 c7 c7 a8 6d 51 8e 48 89 c6 b8 01 00 00 00 d3 e0 89 c1 e8 21 97 d2 ff <0f> 0b e9 e5 fe ff ff 48 c7 c6 e0 6d 51 8e 4c 89 ff e8 eb 23 fc ff
[ 0.045633] RSP: 0000:ffffd592c002f828 EFLAGS: 00010082
[ 0.045633] RAX: 0000000000000000 RBX: ffff8e363b2cbc80 RCX: ffffffff8f1f0c68
[ 0.045633] RDX: 0000000000000000 RSI: 00000000fffeffff RDI: 0000000000000001
[ 0.045633] RBP: 0000000000000003 R08: 0000000000000000 R09: ffffd592c002f6d0
[ 0.045633] R10: ffffd592c002f6c8 R11: ffffffff8f370ca8 R12: 0000000000000008
[ 0.045633] R13: 0000000000038e98 R14: 0000000000000003 R15: fffffb9c40e3a600
[ 0.045633] FS: 0000000000000000(0000) GS:ffff8e3639f00000(0000) knlGS:0000000000000000
[ 0.045633] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 0.045633] CR2: 0000000000000000 CR3: 000000001bc34001 CR4: 00000000007706f0
[ 0.045633] PKRU: 55555554
[ 0.045633] Call Trace:
[ 0.045633] <TASK>
[ 0.045633] rmqueue_bulk+0x541/0x880
[ 0.045633] __rmqueue_pcplist+0x233/0x2c0
[ 0.045633] rmqueue.constprop.0+0x4b6/0xe80
[ 0.045633] ? _raw_spin_unlock+0xa/0x30
[ 0.045633] ? rmqueue.constprop.0+0x557/0xe80
[ 0.045633] ? _raw_spin_unlock_irqrestore+0xa/0x30
[ 0.045633] get_page_from_freelist+0x16e/0x5f0
[ 0.045633] __alloc_pages_noprof+0x18a/0x350
[ 0.045633] alloc_pages_mpol_noprof+0xf2/0x1e0
[ 0.045633] ? shuffle_freelist+0x126/0x1b0
[ 0.045633] allocate_slab+0x2b3/0x410
[ 0.045633] ___slab_alloc+0x396/0x830
[ 0.045633] ? switch_hrtimer_base+0x8e/0x190
[ 0.045633] ? timerqueue_add+0x9b/0xc0
[ 0.045633] ? dup_task_struct+0x2d/0x1b0
[ 0.045633] ? _raw_spin_unlock_irqrestore+0xa/0x30
[ 0.045633] ? start_dl_timer+0xb0/0x140
[ 0.045633] kmem_cache_alloc_node_noprof+0x271/0x2e0
[ 0.045633] ? dup_task_struct+0x2d/0x1b0
[ 0.045633] dup_task_struct+0x2d/0x1b0
[ 0.045633] copy_process+0x195/0x17e0
[ 0.045633] kernel_clone+0x9a/0x3b0
[ 0.045633] ? psi_task_switch+0x105/0x290
[ 0.045633] kernel_thread+0x6b/0x90
[ 0.045633] ? __pfx_kthread+0x10/0x10
[ 0.045633] kthreadd+0x276/0x2d0
[ 0.045633] ? __pfx_kthreadd+0x10/0x10
[ 0.045633] ret_from_fork+0x30/0x50
[ 0.045633] ? __pfx_kthreadd+0x10/0x10
[ 0.045633] ret_from_fork_asm+0x1a/0x30
[ 0.045633] </TASK>
[ 0.045633] ---[ end trace 0000000000000000 ]---
> >
>
next prev parent reply other threads:[~2026-02-10 8:34 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-03 8:02 Benjamin Herrenschmidt
2026-02-03 18:40 ` Mike Rapoport
2026-02-03 19:53 ` Benjamin Herrenschmidt
2026-02-04 7:39 ` Mike Rapoport
2026-02-04 9:02 ` Benjamin Herrenschmidt
2026-02-06 10:33 ` Mike Rapoport
2026-02-10 1:04 ` Benjamin Herrenschmidt
2026-02-10 2:10 ` Benjamin Herrenschmidt
2026-02-10 6:17 ` Benjamin Herrenschmidt
2026-02-10 8:34 ` Benjamin Herrenschmidt [this message]
2026-02-10 14:32 ` Mike Rapoport
2026-02-10 23:23 ` Benjamin Herrenschmidt
2026-02-11 5:20 ` Mike Rapoport
2026-02-16 5:34 ` Benjamin Herrenschmidt
2026-02-16 6:51 ` Benjamin Herrenschmidt
2026-02-16 4:53 ` Benjamin Herrenschmidt
2026-02-16 15:28 ` Mike Rapoport
2026-02-16 10:36 ` Alexander Potapenko
2026-02-17 8:28 ` [PATCH v2] " Benjamin Herrenschmidt
2026-02-17 12:32 ` Mike Rapoport
2026-02-17 22:00 ` Benjamin Herrenschmidt
2026-02-17 21:47 ` Benjamin Herrenschmidt
2026-02-18 0:15 ` Benjamin Herrenschmidt
2026-02-18 8:05 ` Mike Rapoport
2026-02-19 2:48 ` Benjamin Herrenschmidt
2026-02-19 10:16 ` Mike Rapoport
2026-02-19 22:46 ` Benjamin Herrenschmidt
2026-02-20 4:57 ` Benjamin Herrenschmidt
2026-02-20 9:09 ` Mike Rapoport
2026-02-20 9:00 ` Mike Rapoport
2026-02-20 5:12 ` Benjamin Herrenschmidt
2026-02-20 5:15 ` Benjamin Herrenschmidt
2026-02-20 5:47 ` Benjamin Herrenschmidt
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