11. September 2023.
Hallo,
Ich möchte Ihnen einen Geschäftsvorschlag mitteilen. Für weitere
Details antworten Sie auf Englisch.
Grüße
Frau Victoria Cleland
_______________________
Sekretär: Essaoui Alan
From: Tuo Li <islituo(a)gmail.com>
[ Upstream commit 2e63972a2de14482d0eae1a03a73e379f1c3f44c ]
The variable crtc->state->event is often protected by the lock
crtc->dev->event_lock when is accessed. However, it is accessed as a
condition of an if statement in exynos_drm_crtc_atomic_disable() without
holding the lock:
if (crtc->state->event && !crtc->state->active)
However, if crtc->state->event is changed to NULL by another thread right
after the conditions of the if statement is checked to be true, a
null-pointer dereference can occur in drm_crtc_send_vblank_event():
e->pipe = pipe;
To fix this possible null-pointer dereference caused by data race, the
spin lock coverage is extended to protect the if statement as well as the
function call to drm_crtc_send_vblank_event().
Reported-by: BassCheck <bass(a)buaa.edu.cn>
Link: https://sites.google.com/view/basscheck/home
Signed-off-by: Tuo Li <islituo(a)gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski(a)linaro.org>
Added relevant link.
Signed-off-by: Inki Dae <inki.dae(a)samsung.com>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
drivers/gpu/drm/exynos/exynos_drm_crtc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
index 4787560bf93e7..e1aa518ea0ba1 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
@@ -43,13 +43,12 @@ static void exynos_drm_crtc_atomic_disable(struct drm_crtc *crtc,
if (exynos_crtc->ops->disable)
exynos_crtc->ops->disable(exynos_crtc);
+ spin_lock_irq(&crtc->dev->event_lock);
if (crtc->state->event && !crtc->state->active) {
- spin_lock_irq(&crtc->dev->event_lock);
drm_crtc_send_vblank_event(crtc, crtc->state->event);
- spin_unlock_irq(&crtc->dev->event_lock);
-
crtc->state->event = NULL;
}
+ spin_unlock_irq(&crtc->dev->event_lock);
}
static int exynos_crtc_atomic_check(struct drm_crtc *crtc,
--
2.40.1
From: Hugo Villeneuve <hvilleneuve(a)dimonoff.com>
Add some clarifications for patches that have dependencies within the
patch series.
Signed-off-by: Hugo Villeneuve <hvilleneuve(a)dimonoff.com>
---
Changes since v1: rebase on latest torvalds/master
Documentation/process/stable-kernel-rules.rst | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/Documentation/process/stable-kernel-rules.rst b/Documentation/process/stable-kernel-rules.rst
index 41f1e07abfdf..1704f1c686d0 100644
--- a/Documentation/process/stable-kernel-rules.rst
+++ b/Documentation/process/stable-kernel-rules.rst
@@ -101,6 +101,19 @@ comment:
git cherry-pick fd21073
git cherry-pick <this commit>
+ Note that for a patch series, you do not have to list as prerequisites the
+ patches present in the series itself. For example, if you have the following
+ patch series:
+
+ .. code-block:: none
+
+ patch1
+ patch2
+
+ where patch2 depends on patch1, you do not have to list patch1 as
+ prerequisite of patch2 if you have already marked patch1 for stable
+ inclusion.
+
* For patches that may have kernel version prerequisites specify them using
the following format in the sign-off area:
base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d
--
2.30.2
The patch titled
Subject: mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-page_alloc-fix-cma-and-highatomic-landing-on-the-wrong-buddy-list.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Johannes Weiner <hannes(a)cmpxchg.org>
Subject: mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list
Date: Mon, 11 Sep 2023 14:11:08 -0400
Commit 4b23a68f9536 ("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 overriden, 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(a)techsingularity.net: updated changelog]
Link: https://lkml.kernel.org/r/20230911181108.GA104295@cmpxchg.org
Fixes: 4b23a68f9536 ("mm/page_alloc: protect PCP lists with a spinlock")
Signed-off-by: Johannes Weiner <hannes(a)cmpxchg.org>
Reported-by: Joe Liu <joe.liu(a)mediatek.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/page_alloc.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-fix-cma-and-highatomic-landing-on-the-wrong-buddy-list
+++ a/mm/page_alloc.c
@@ -2400,7 +2400,7 @@ void free_unref_page(struct page *page,
struct per_cpu_pages *pcp;
struct zone *zone;
unsigned long pfn = page_to_pfn(page);
- int migratetype;
+ int migratetype, pcpmigratetype;
if (!free_unref_page_prepare(page, pfn, order))
return;
@@ -2408,24 +2408,24 @@ void free_unref_page(struct page *page,
/*
* We only track unmovable, reclaimable and movable on pcp lists.
* Place ISOLATE pages on the isolated list because they are being
- * offlined but treat HIGHATOMIC as movable pages so we can get those
- * areas back if necessary. Otherwise, we may have to free
+ * offlined but treat HIGHATOMIC and CMA as movable pages so we can
+ * get those areas back if necessary. Otherwise, we may have to free
* excessively into the page allocator
*/
- migratetype = get_pcppage_migratetype(page);
+ migratetype = pcpmigratetype = get_pcppage_migratetype(page);
if (unlikely(migratetype >= MIGRATE_PCPTYPES)) {
if (unlikely(is_migrate_isolate(migratetype))) {
free_one_page(page_zone(page), page, pfn, order, migratetype, FPI_NONE);
return;
}
- migratetype = MIGRATE_MOVABLE;
+ pcpmigratetype = MIGRATE_MOVABLE;
}
zone = page_zone(page);
pcp_trylock_prepare(UP_flags);
pcp = pcp_spin_trylock(zone->per_cpu_pageset);
if (pcp) {
- free_unref_page_commit(zone, pcp, page, migratetype, order);
+ free_unref_page_commit(zone, pcp, page, pcpmigratetype, order);
pcp_spin_unlock(pcp);
} else {
/*
_
Patches currently in -mm which might be from hannes(a)cmpxchg.org are
mm-page_alloc-fix-cma-and-highatomic-landing-on-the-wrong-buddy-list.patch
mm-page_alloc-remove-pcppage-migratetype-caching.patch
mm-page_alloc-fix-up-block-types-when-merging-compatible-blocks.patch
mm-page_alloc-move-free-pages-when-converting-block-during-isolation.patch
mm-page_alloc-fix-move_freepages_block-range-error.patch
mm-page_alloc-fix-freelist-movement-during-block-conversion.patch
mm-page_alloc-consolidate-free-page-accounting.patch