Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-09-20 15:03:04 +00:00
Code Issues Packages Projects Releases Wiki Activity
A mirror of the official Linux kernel repository just in case
1,215,389 Commits 7 Branches 853 Tags 5.7 GiB
C 97.6%
Assembly 1%
Shell 0.5%
Python 0.3%
Makefile 0.3%
7b086755fb
Go to file
Johannes Weiner 7b086755fb mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list 
Commit 4b23a68f95 ("mm/page_alloc: protect PCP lists with a spinlock")
bypasses the pcplist on lock contention and returns the page directly to
the buddy list of the page's migratetype.

For pages that don't have their own pcplist, such as CMA and HIGHATOMIC,
the migratetype is temporarily updated such that the page can hitch a ride
on the MOVABLE pcplist.  Their true type is later reassessed when flushing
in free_pcppages_bulk().  However, when lock contention is detected after
the type was already overridden, the bypass will then put the page on the
wrong buddy list.

Once on the MOVABLE buddy list, the page becomes eligible for fallbacks
and even stealing.  In the case of HIGHATOMIC, otherwise ineligible
allocations can dip into the highatomic reserves.  In the case of CMA, the
page can be lost from the CMA region permanently.

Use a separate pcpmigratetype variable for the pcplist override.  Use the
original migratetype when going directly to the buddy.  This fixes the bug
and should make the intentions more obvious in the code.

Originally sent here to address the HIGHATOMIC case:
https://lore.kernel.org/lkml/20230821183733.106619-4-hannes@cmpxchg.org/

Changelog updated in response to the CMA-specific bug report.

[mgorman@techsingularity.net: updated changelog]
Link: https://lkml.kernel.org/r/20230911181108.GA104295@cmpxchg.org
Fixes: 4b23a68f95 ("mm/page_alloc: protect PCP lists with a spinlock")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Joe Liu <joe.liu@mediatek.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-09-19 13:21:32 -07:00
arch sh: mm: re-add lost __ref to ioremap_prot() to fix modpost warning 2023-09-19 13:21:32 -07:00
block blk-mq: fix tags UAF when shrinking q->nr_hw_queues 2023-09-11 16:17:34 -06:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto This update includes the following changes: 2023-08-29 11:23:29 -07:00
Documentation Driver core fix for 6.6-rc2 2023-09-16 11:26:52 -07:00
drivers SCSI fixes on 20230916 2023-09-16 11:54:48 -07:00
fs stat: remove no-longer-used helper macros 2023-09-17 10:46:12 -07:00
include Misc fixes: 2023-09-17 11:13:37 -07:00
init workqueue: Changes for v6.6 2023-09-01 16:06:32 -07:00
io_uring io_uring/net: fix iter retargeting for selected buf 2023-09-14 10:12:55 -06:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel Fix a performance regression on large SMT systems, an Intel SMT4 2023-09-17 11:10:23 -07:00
lib linux-kselftest-kunit-6.6-rc2 2023-09-12 09:05:49 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list 2023-09-19 13:21:32 -07:00
net kcm: Fix error handling for SOCK_DGRAM in kcm_sendmsg(). 2023-09-14 10:43:51 +02:00
rust Documentation work keeps chugging along; stuff for 6.6 includes: 2023-08-30 20:05:42 -07:00
samples VFIO updates for v6.6-rc1 2023-08-30 20:36:01 -07:00
scripts Kbuild fixes for v6.6 2023-09-16 15:27:00 -07:00
security selinux: fix handling of empty opts in selinux_fs_context_submount() 2023-09-12 17:31:08 -04:00
sound sound fixes for 6.6-rc1 2023-09-08 13:07:50 -07:00
tools Fix a cold functions related false-positive objtool warning 2023-09-17 10:59:37 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap for-linus-2023083101 2023-09-01 12:31:44 -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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS This pull-request renames the genpd subsystem to pmdomain. 2023-09-13 14:18:19 -07:00
Makefile Linux 6.6-rc2 2023-09-17 14:40:24 -07:00
README

README 

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.