All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, linux-mm@kvack.org,
	mgorman@techsingularity.net, mm-commits@vger.kernel.org,
	opendmb@gmail.com, peterz@infradead.org,
	torvalds@linux-foundation.org, vbabka@suse.cz
Subject: [patch 03/10] mm/page_alloc: don't corrupt pcppage_migratetype
Date: Thu, 19 Aug 2021 19:04:12 -0700	[thread overview]
Message-ID: <20210820020412.EA2QVRAWd%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210819190327.14fc4e97102e1af7929e30af@linux-foundation.org>

From: Doug Berger <opendmb@gmail.com>
Subject: mm/page_alloc: don't corrupt pcppage_migratetype

When placing pages on a pcp list, migratetype values over MIGRATE_PCPTYPES
get added to the MIGRATE_MOVABLE pcp list.

However, the actual migratetype is preserved in the page and should not be
changed to MIGRATE_MOVABLE or the page may end up on the wrong free_list.

The impact is that HIGHATOMIC or CMA pages getting bulk freed from the PCP
lists could potentially end up on the wrong buddy list.  There are various
consequences but minimally NR_FREE_CMA_PAGES accounting could get screwed
up.

[mgorman@techsingularity.net: changelog update]
Link: https://lkml.kernel.org/r/20210811182917.2607994-1-opendmb@gmail.com
Fixes: df1acc856923 ("mm/page_alloc: avoid conflating IRQs disabled with zone->lock")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |   25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

--- a/mm/page_alloc.c~mm-page_alloc-dont-corrupt-pcppage_migratetype
+++ a/mm/page_alloc.c
@@ -3453,19 +3453,10 @@ void free_unref_page_list(struct list_he
 		 * comment in free_unref_page.
 		 */
 		migratetype = get_pcppage_migratetype(page);
-		if (unlikely(migratetype >= MIGRATE_PCPTYPES)) {
-			if (unlikely(is_migrate_isolate(migratetype))) {
-				list_del(&page->lru);
-				free_one_page(page_zone(page), page, pfn, 0,
-							migratetype, FPI_NONE);
-				continue;
-			}
-
-			/*
-			 * Non-isolated types over MIGRATE_PCPTYPES get added
-			 * to the MIGRATE_MOVABLE pcp list.
-			 */
-			set_pcppage_migratetype(page, MIGRATE_MOVABLE);
+		if (unlikely(is_migrate_isolate(migratetype))) {
+			list_del(&page->lru);
+			free_one_page(page_zone(page), page, pfn, 0, migratetype, FPI_NONE);
+			continue;
 		}
 
 		set_page_private(page, pfn);
@@ -3475,7 +3466,15 @@ void free_unref_page_list(struct list_he
 	list_for_each_entry_safe(page, next, list, lru) {
 		pfn = page_private(page);
 		set_page_private(page, 0);
+
+		/*
+		 * Non-isolated types over MIGRATE_PCPTYPES get added
+		 * to the MIGRATE_MOVABLE pcp list.
+		 */
 		migratetype = get_pcppage_migratetype(page);
+		if (unlikely(migratetype >= MIGRATE_PCPTYPES))
+			migratetype = MIGRATE_MOVABLE;
+
 		trace_mm_page_free_batched(page);
 		free_unref_page_commit(page, pfn, migratetype, 0);
 
_

  parent reply	other threads:[~2021-08-20  2:04 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-20  2:03 incoming Andrew Morton
2021-08-20  2:04 ` [patch 01/10] Revert "mm/shmem: fix shmem_swapin() race with swapoff" Andrew Morton
2021-08-20  2:04 ` [patch 02/10] Revert "mm: swap: check if swap backing device is congested or not" Andrew Morton
2021-08-20  2:04 ` Andrew Morton [this message]
2021-08-20  2:04 ` [patch 04/10] mmflags.h: add missing __GFP_ZEROTAGS and __GFP_SKIP_KASAN_POISON names Andrew Morton
2021-08-20  2:04 ` [patch 05/10] MAINTAINERS: update ClangBuiltLinux IRC chat Andrew Morton
2021-08-20  2:04 ` [patch 06/10] mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim Andrew Morton
2021-08-20  2:04 ` [patch 07/10] mm/hwpoison: retry with shake_page() for unhandlable pages Andrew Morton
2021-08-20  2:04 ` [patch 08/10] mm: vmscan: fix missing psi annotation for node_reclaim() Andrew Morton
2021-08-20  2:04 ` [patch 09/10] kfence: fix is_kfence_address() for addresses below KFENCE_POOL_SIZE Andrew Morton
2021-08-20  2:04 ` [patch 10/10] hugetlb: don't pass page cache pages to restore_reserve_on_error Andrew Morton

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210820020412.EA2QVRAWd%akpm@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mgorman@techsingularity.net \
    --cc=mm-commits@vger.kernel.org \
    --cc=opendmb@gmail.com \
    --cc=peterz@infradead.org \
    --cc=torvalds@linux-foundation.org \
    --cc=vbabka@suse.cz \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.