Re: [PATCH] mm: Fix memblock_free_late() when using deferred struct page

[Mike Rapoport <rppt@kernel.org>]

Hi Ben,

On Tue, Feb 10, 2026 at 07:34:15PM +1100, Benjamin Herrenschmidt wrote:
> 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):
> 
>  .../...

Do you mind sending the entire log?
 
> 
> [    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 ]---
> 
> > > 
> > 
> 

-- 
Sincerely yours,
Mike.