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Alexander Gordeev 7838a4eb8a mm/page_alloc: change all pageblocks migrate type on coalescing
When a page is freed it coalesces with a buddy into a higher order page
while possible.  When the buddy page migrate type differs, it is expected
to be updated to match the one of the page being freed.

However, only the first pageblock of the buddy page is updated, while the
rest of the pageblocks are left unchanged.

That causes warnings in later expand() and other code paths (like below),
since an inconsistency between migration type of the list containing the
page and the page-owned pageblocks migration types is introduced.

[  308.986589] ------------[ cut here ]------------
[  308.987227] page type is 0, passed migratetype is 1 (nr=256)
[  308.987275] WARNING: CPU: 1 PID: 5224 at mm/page_alloc.c:812 expand+0x23c/0x270
[  308.987293] Modules linked in: algif_hash(E) af_alg(E) nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) nft_chain_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) nf_tables(E) s390_trng(E) vfio_ccw(E) mdev(E) vfio_iommu_type1(E) vfio(E) sch_fq_codel(E) drm(E) i2c_core(E) drm_panel_orientation_quirks(E) loop(E) nfnetlink(E) vsock_loopback(E) vmw_vsock_virtio_transport_common(E) vsock(E) ctcm(E) fsm(E) diag288_wdt(E) watchdog(E) zfcp(E) scsi_transport_fc(E) ghash_s390(E) prng(E) aes_s390(E) des_generic(E) des_s390(E) libdes(E) sha3_512_s390(E) sha3_256_s390(E) sha_common(E) paes_s390(E) crypto_engine(E) pkey_cca(E) pkey_ep11(E) zcrypt(E) rng_core(E) pkey_pckmo(E) pkey(E) autofs4(E)
[  308.987439] Unloaded tainted modules: hmac_s390(E):2
[  308.987650] CPU: 1 UID: 0 PID: 5224 Comm: mempig_verify Kdump: loaded Tainted: G            E       6.18.0-gcc-bpf-debug #431 PREEMPT
[  308.987657] Tainted: [E]=UNSIGNED_MODULE
[  308.987661] Hardware name: IBM 3906 M04 704 (z/VM 7.3.0)
[  308.987666] Krnl PSW : 0404f00180000000 00000349976fa600 (expand+0x240/0x270)
[  308.987676]            R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3
[  308.987682] Krnl GPRS: 0000034980000004 0000000000000005 0000000000000030 000003499a0e6d88
[  308.987688]            0000000000000005 0000034980000005 000002be803ac000 0000023efe6c8300
[  308.987692]            0000000000000008 0000034998d57290 000002be00000100 0000023e00000008
[  308.987696]            0000000000000000 0000000000000000 00000349976fa5fc 000002c99b1eb6f0
[  308.987708] Krnl Code: 00000349976fa5f0: c020008a02f2	larl	%r2,000003499883abd4
                          00000349976fa5f6: c0e5ffe3f4b5	brasl	%r14,0000034997378f60
                         #00000349976fa5fc: af000000		mc	0,0
                         >00000349976fa600: a7f4ff4c		brc	15,00000349976fa498
                          00000349976fa604: b9040026		lgr	%r2,%r6
                          00000349976fa608: c0300088317f	larl	%r3,0000034998800906
                          00000349976fa60e: c0e5fffdb6e1	brasl	%r14,00000349976b13d0
                          00000349976fa614: af000000		mc	0,0
[  308.987734] Call Trace:
[  308.987738]  [<00000349976fa600>] expand+0x240/0x270
[  308.987744] ([<00000349976fa5fc>] expand+0x23c/0x270)
[  308.987749]  [<00000349976ff95e>] rmqueue_bulk+0x71e/0x940
[  308.987754]  [<00000349976ffd7e>] __rmqueue_pcplist+0x1fe/0x2a0
[  308.987759]  [<0000034997700966>] rmqueue.isra.0+0xb46/0xf40
[  308.987763]  [<0000034997703ec8>] get_page_from_freelist+0x198/0x8d0
[  308.987768]  [<0000034997706fa8>] __alloc_frozen_pages_noprof+0x198/0x400
[  308.987774]  [<00000349977536f8>] alloc_pages_mpol+0xb8/0x220
[  308.987781]  [<0000034997753bf6>] folio_alloc_mpol_noprof+0x26/0xc0
[  308.987786]  [<0000034997753e4c>] vma_alloc_folio_noprof+0x6c/0xa0
[  308.987791]  [<0000034997775b22>] vma_alloc_anon_folio_pmd+0x42/0x240
[  308.987799]  [<000003499777bfea>] __do_huge_pmd_anonymous_page+0x3a/0x210
[  308.987804]  [<00000349976cb08e>] __handle_mm_fault+0x4de/0x500
[  308.987809]  [<00000349976cb14c>] handle_mm_fault+0x9c/0x3a0
[  308.987813]  [<000003499734d70e>] do_exception+0x1de/0x540
[  308.987822]  [<0000034998387390>] __do_pgm_check+0x130/0x220
[  308.987830]  [<000003499839a934>] pgm_check_handler+0x114/0x160
[  308.987838] 3 locks held by mempig_verify/5224:
[  308.987842]  #0: 0000023ea44c1e08 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0xb2/0x2a0
[  308.987859]  #1: 0000023ee4d41b18 (&pcp->lock){+.+.}-{2:2}, at: rmqueue.isra.0+0xad6/0xf40
[  308.987871]  #2: 0000023efe6c8998 (&zone->lock){..-.}-{2:2}, at: rmqueue_bulk+0x5a/0x940
[  308.987886] Last Breaking-Event-Address:
[  308.987890]  [<0000034997379096>] __warn_printk+0x136/0x140
[  308.987897] irq event stamp: 52330356
[  308.987901] hardirqs last  enabled at (52330355): [<000003499838742e>] __do_pgm_check+0x1ce/0x220
[  308.987907] hardirqs last disabled at (52330356): [<000003499839932e>] _raw_spin_lock_irqsave+0x9e/0xe0
[  308.987913] softirqs last  enabled at (52329882): [<0000034997383786>] handle_softirqs+0x2c6/0x530
[  308.987922] softirqs last disabled at (52329859): [<0000034997382f86>] __irq_exit_rcu+0x126/0x140
[  308.987929] ---[ end trace 0000000000000000 ]---
[  308.987936] ------------[ cut here ]------------
[  308.987940] page type is 0, passed migratetype is 1 (nr=256)
[  308.987951] WARNING: CPU: 1 PID: 5224 at mm/page_alloc.c:860 __del_page_from_free_list+0x1be/0x1e0
[  308.987960] Modules linked in: algif_hash(E) af_alg(E) nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) nft_chain_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) nf_tables(E) s390_trng(E) vfio_ccw(E) mdev(E) vfio_iommu_type1(E) vfio(E) sch_fq_codel(E) drm(E) i2c_core(E) drm_panel_orientation_quirks(E) loop(E) nfnetlink(E) vsock_loopback(E) vmw_vsock_virtio_transport_common(E) vsock(E) ctcm(E) fsm(E) diag288_wdt(E) watchdog(E) zfcp(E) scsi_transport_fc(E) ghash_s390(E) prng(E) aes_s390(E) des_generic(E) des_s390(E) libdes(E) sha3_512_s390(E) sha3_256_s390(E) sha_common(E) paes_s390(E) crypto_engine(E) pkey_cca(E) pkey_ep11(E) zcrypt(E) rng_core(E) pkey_pckmo(E) pkey(E) autofs4(E)
[  308.988070] Unloaded tainted modules: hmac_s390(E):2
[  308.988087] CPU: 1 UID: 0 PID: 5224 Comm: mempig_verify Kdump: loaded Tainted: G        W   E       6.18.0-gcc-bpf-debug #431 PREEMPT
[  308.988095] Tainted: [W]=WARN, [E]=UNSIGNED_MODULE
[  308.988100] Hardware name: IBM 3906 M04 704 (z/VM 7.3.0)
[  308.988105] Krnl PSW : 0404f00180000000 00000349976f9e32 (__del_page_from_free_list+0x1c2/0x1e0)
[  308.988118]            R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3
[  308.988127] Krnl GPRS: 0000034980000004 0000000000000005 0000000000000030 000003499a0e6d88
[  308.988133]            0000000000000005 0000034980000005 0000034998d57290 0000023efe6c8300
[  308.988139]            0000000000000001 0000000000000008 000002be00000100 000002be803ac000
[  308.988144]            0000000000000000 0000000000000001 00000349976f9e2e 000002c99b1eb728
[  308.988153] Krnl Code: 00000349976f9e22: c020008a06d9	larl	%r2,000003499883abd4
                          00000349976f9e28: c0e5ffe3f89c	brasl	%r14,0000034997378f60
                         #00000349976f9e2e: af000000		mc	0,0
                         >00000349976f9e32: a7f4ff4e		brc	15,00000349976f9cce
                          00000349976f9e36: b904002b		lgr	%r2,%r11
                          00000349976f9e3a: c030008a06e7	larl	%r3,000003499883ac08
                          00000349976f9e40: c0e5fffdbac8	brasl	%r14,00000349976b13d0
                          00000349976f9e46: af000000		mc	0,0
[  308.988184] Call Trace:
[  308.988188]  [<00000349976f9e32>] __del_page_from_free_list+0x1c2/0x1e0
[  308.988195] ([<00000349976f9e2e>] __del_page_from_free_list+0x1be/0x1e0)
[  308.988202]  [<00000349976ff946>] rmqueue_bulk+0x706/0x940
[  308.988208]  [<00000349976ffd7e>] __rmqueue_pcplist+0x1fe/0x2a0
[  308.988214]  [<0000034997700966>] rmqueue.isra.0+0xb46/0xf40
[  308.988221]  [<0000034997703ec8>] get_page_from_freelist+0x198/0x8d0
[  308.988227]  [<0000034997706fa8>] __alloc_frozen_pages_noprof+0x198/0x400
[  308.988233]  [<00000349977536f8>] alloc_pages_mpol+0xb8/0x220
[  308.988240]  [<0000034997753bf6>] folio_alloc_mpol_noprof+0x26/0xc0
[  308.988247]  [<0000034997753e4c>] vma_alloc_folio_noprof+0x6c/0xa0
[  308.988253]  [<0000034997775b22>] vma_alloc_anon_folio_pmd+0x42/0x240
[  308.988260]  [<000003499777bfea>] __do_huge_pmd_anonymous_page+0x3a/0x210
[  308.988267]  [<00000349976cb08e>] __handle_mm_fault+0x4de/0x500
[  308.988273]  [<00000349976cb14c>] handle_mm_fault+0x9c/0x3a0
[  308.988279]  [<000003499734d70e>] do_exception+0x1de/0x540
[  308.988286]  [<0000034998387390>] __do_pgm_check+0x130/0x220
[  308.988293]  [<000003499839a934>] pgm_check_handler+0x114/0x160
[  308.988300] 3 locks held by mempig_verify/5224:
[  308.988305]  #0: 0000023ea44c1e08 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0xb2/0x2a0
[  308.988322]  #1: 0000023ee4d41b18 (&pcp->lock){+.+.}-{2:2}, at: rmqueue.isra.0+0xad6/0xf40
[  308.988334]  #2: 0000023efe6c8998 (&zone->lock){..-.}-{2:2}, at: rmqueue_bulk+0x5a/0x940
[  308.988346] Last Breaking-Event-Address:
[  308.988350]  [<0000034997379096>] __warn_printk+0x136/0x140
[  308.988356] irq event stamp: 52330356
[  308.988360] hardirqs last  enabled at (52330355): [<000003499838742e>] __do_pgm_check+0x1ce/0x220
[  308.988366] hardirqs last disabled at (52330356): [<000003499839932e>] _raw_spin_lock_irqsave+0x9e/0xe0
[  308.988373] softirqs last  enabled at (52329882): [<0000034997383786>] handle_softirqs+0x2c6/0x530
[  308.988380] softirqs last disabled at (52329859): [<0000034997382f86>] __irq_exit_rcu+0x126/0x140
[  308.988388] ---[ end trace 0000000000000000 ]---

Link: https://lkml.kernel.org/r/20251215081002.3353900A9c-agordeev@linux.ibm.com
Link: https://lkml.kernel.org/r/20251212151457.3898073Add-agordeev@linux.ibm.com
Fixes: e6cf9e1c4c ("mm: page_alloc: fix up block types when merging compatible blocks")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Closes: https://lore.kernel.org/linux-mm/87wmalyktd.fsf@linux.ibm.com/
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Marc Hartmayer <mhartmay@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
History 2025-12-23 11:23:12 -08:00
arch Miscellaneous x86 fixes: 2025-12-21 14:41:29 -08:00
block block-6.19-20251218 2025-12-20 09:48:56 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Networking changes for 6.19. 2025-12-03 17:24:33 -08:00
Documentation Input updates for v6.19-rc1 2025-12-21 15:21:10 -08:00
drivers Input updates for v6.19-rc1 2025-12-21 15:21:10 -08:00
fs Fixes for 6.19-rc2 2025-12-20 12:45:35 -08:00
include mm: leafops.h: correct kernel-doc function param. names 2025-12-23 11:23:12 -08:00
init Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
io_uring io_uring-6.19-20251218 2025-12-20 09:38:56 -08:00
ipc Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
kernel Fix IRQ thread affinity flags setup regression. 2025-12-21 14:34:13 -08:00
lib idr: fix idr_alloc() returning an ID out of range 2025-12-23 11:23:11 -08:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm mm/page_alloc: change all pageblocks migrate type on coalescing 2025-12-23 11:23:12 -08:00
net Including fixes from netfilter and CAN. 2025-12-19 07:55:35 +12:00
rust USB/Thunderbolt changes for 6.19-rc1 2025-12-06 18:42:12 -08:00
samples USB/Thunderbolt changes for 6.19-rc1 2025-12-06 18:42:12 -08:00
scripts Coccinelle: pm_runtime: Fix typo in report message 2025-12-21 21:04:52 +01:00
security Trivial optimization. 2025-12-14 15:21:02 +12:00
sound soundwire updates for 6.19 2025-12-13 16:26:55 +12:00
tools idr: fix idr_alloc() returning an ID out of range 2025-12-23 11:23:11 -08:00
usr initramfs: add gen_init_cpio to hostprogs unconditionally 2025-11-26 21:55:40 +01:00
virt KVM fixes for 6.19-rc1 2025-12-18 18:38:45 +01:00
.clang-format s390/pci: Fix cyclic dead-lock in zpci_zdev_put() and zpci_scan_devices() 2025-12-14 11:03:58 +01:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: kbuild: add proc macro library support 2025-11-24 17:15:36 +01:00
.mailmap mailmap: update entry for Bartosz Golaszewski 2025-12-23 11:23:10 -08:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Including fixes from netfilter and CAN. 2025-12-19 07:55:35 +12:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS MAINTAINERS: add Mike Rapoport as maintainer for userfaultfd 2025-12-23 11:23:10 -08:00
Makefile Linux 6.19-rc2 2025-12-21 15:52:04 -08:00
README README: restructure with role-based documentation and guidelines 2025-11-29 08:40:33 -07:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst



Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst