The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x e16fdd4f754048d6e23c56bd8d920b71e41e3777
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010523-protozoan-pelt-bf14@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e16fdd4f754048d6e23c56bd8d920b71e41e3777 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj(a)kernel.org>
Date: Sat, 1 Nov 2025 11:19:56 -0700
Subject: [PATCH] mm/damon/tests/core-kunit: handle allocation failures in
damon_test_regions()
damon_test_regions() is assuming all dynamic memory allocation in it will
succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-3-sj@kernel.org
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj(a)kernel.org>
Cc: Brendan Higgins <brendan.higgins(a)linux.dev>
Cc: David Gow <davidgow(a)google.com>
Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com>
Cc: <stable(a)vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 69ca44f9270b..a2c9ee7a5de1 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -20,11 +20,17 @@ static void damon_test_regions(struct kunit *test)
struct damon_target *t;
r = damon_new_region(1, 2);
+ if (!r)
+ kunit_skip(test, "region alloc fail");
KUNIT_EXPECT_EQ(test, 1ul, r->ar.start);
KUNIT_EXPECT_EQ(test, 2ul, r->ar.end);
KUNIT_EXPECT_EQ(test, 0u, r->nr_accesses);
t = damon_new_target();
+ if (!t) {
+ damon_free_region(r);
+ kunit_skip(test, "target alloc fail");
+ }
KUNIT_EXPECT_EQ(test, 0u, damon_nr_regions(t));
damon_add_region(r, t);
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 0a63a0e7570b9b2631dfb8d836dc572709dce39e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010513-icon-slit-98fa@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 0a63a0e7570b9b2631dfb8d836dc572709dce39e Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj(a)kernel.org>
Date: Sat, 1 Nov 2025 11:20:13 -0700
Subject: [PATCH] mm/damon/tests/vaddr-kunit: handle alloc failures on
damon_test_split_evenly_succ()
damon_test_split_evenly_succ() is assuming all dynamic memory allocation
in it will succeed. Those are indeed likely in the real use cases since
those allocations are too small to fail, but theoretically those could
fail. In the case, inappropriate memory access can happen. Fix it by
appropriately cleanup pre-allocated memory and skip the execution of the
remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-20-sj@kernel.org
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj(a)kernel.org>
Cc: Brendan Higgins <brendan.higgins(a)linux.dev>
Cc: David Gow <davidgow(a)google.com>
Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com>
Cc: <stable(a)vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
index 1b0f21c2e376..30dc5459f1d2 100644
--- a/mm/damon/tests/vaddr-kunit.h
+++ b/mm/damon/tests/vaddr-kunit.h
@@ -284,10 +284,17 @@ static void damon_test_split_evenly_succ(struct kunit *test,
unsigned long start, unsigned long end, unsigned int nr_pieces)
{
struct damon_target *t = damon_new_target();
- struct damon_region *r = damon_new_region(start, end);
+ struct damon_region *r;
unsigned long expected_width = (end - start) / nr_pieces;
unsigned long i = 0;
+ if (!t)
+ kunit_skip(test, "target alloc fail");
+ r = damon_new_region(start, end);
+ if (!r) {
+ damon_free_target(t);
+ kunit_skip(test, "region alloc fail");
+ }
damon_add_region(r, t);
KUNIT_EXPECT_EQ(test,
damon_va_evenly_split_region(t, r, nr_pieces), 0);
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 2b22d0fcc6320ba29b2122434c1d2f0785fb0a25
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010547-prankish-amuck-8ac0@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 2b22d0fcc6320ba29b2122434c1d2f0785fb0a25 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj(a)kernel.org>
Date: Sat, 1 Nov 2025 11:20:11 -0700
Subject: [PATCH] mm/damon/tests/vaddr-kunit: handle alloc failures on
damon_do_test_apply_three_regions()
damon_do_test_apply_three_regions() is assuming all dynamic memory
allocation in it will succeed. Those are indeed likely in the real use
cases since those allocations are too small to fail, but theoretically
those could fail. In the case, inappropriate memory access can happen.
Fix it by appropriately cleanup pre-allocated memory and skip the
execution of the remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-18-sj@kernel.org
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj(a)kernel.org>
Cc: Brendan Higgins <brendan.higgins(a)linux.dev>
Cc: David Gow <davidgow(a)google.com>
Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com>
Cc: <stable(a)vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
index fce38dd53cf8..484223f19545 100644
--- a/mm/damon/tests/vaddr-kunit.h
+++ b/mm/damon/tests/vaddr-kunit.h
@@ -136,8 +136,14 @@ static void damon_do_test_apply_three_regions(struct kunit *test,
int i;
t = damon_new_target();
+ if (!t)
+ kunit_skip(test, "target alloc fail");
for (i = 0; i < nr_regions / 2; i++) {
r = damon_new_region(regions[i * 2], regions[i * 2 + 1]);
+ if (!r) {
+ damon_destroy_target(t, NULL);
+ kunit_skip(test, "region alloc fail");
+ }
damon_add_region(r, t);
}
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 7890e5b5bb6e386155c6e755fe70e0cdcc77f18e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010502-dispersed-paper-9a89@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7890e5b5bb6e386155c6e755fe70e0cdcc77f18e Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj(a)kernel.org>
Date: Sat, 1 Nov 2025 11:20:12 -0700
Subject: [PATCH] mm/damon/tests/vaddr-kunit: handle alloc failures in
damon_test_split_evenly_fail()
damon_test_split_evenly_fail() is assuming all dynamic memory allocation
in it will succeed. Those are indeed likely in the real use cases since
those allocations are too small to fail, but theoretically those could
fail. In the case, inappropriate memory access can happen. Fix it by
appropriately cleanup pre-allocated memory and skip the execution of the
remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-19-sj@kernel.org
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj(a)kernel.org>
Cc: Brendan Higgins <brendan.higgins(a)linux.dev>
Cc: David Gow <davidgow(a)google.com>
Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com>
Cc: <stable(a)vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
index 484223f19545..1b0f21c2e376 100644
--- a/mm/damon/tests/vaddr-kunit.h
+++ b/mm/damon/tests/vaddr-kunit.h
@@ -256,7 +256,16 @@ static void damon_test_split_evenly_fail(struct kunit *test,
unsigned long start, unsigned long end, unsigned int nr_pieces)
{
struct damon_target *t = damon_new_target();
- struct damon_region *r = damon_new_region(start, end);
+ struct damon_region *r;
+
+ if (!t)
+ kunit_skip(test, "target alloc fail");
+
+ r = damon_new_region(start, end);
+ if (!r) {
+ damon_free_target(t);
+ kunit_skip(test, "region alloc fail");
+ }
damon_add_region(r, t);
KUNIT_EXPECT_EQ(test,
The quilt patch titled
Subject: arm64: kernel: initialize missing kexec_buf->random field
has been removed from the -mm tree. Its filename was
arm64-kernel-initialize-missing-kexec_buf-random-field.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Yeoreum Yun <yeoreum.yun(a)arm.com>
Subject: arm64: kernel: initialize missing kexec_buf->random field
Date: Mon, 1 Dec 2025 10:51:18 +0000
Commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly")
introduced the kexec_buf->random field to enable random placement of
kexec_buf.
However, this field was never properly initialized for kexec images that
do not need to be placed randomly, leading to the following UBSAN warning:
[ +0.364528] ------------[ cut here ]------------
[ +0.000019] UBSAN: invalid-load in ./include/linux/kexec.h:210:12
[ +0.000131] load of value 2 is not a valid value for type 'bool' (aka '_Bool')
[ +0.000003] CPU: 4 UID: 0 PID: 927 Comm: kexec Not tainted 6.18.0-rc7+ #3 PREEMPT(full)
[ +0.000002] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
[ +0.000000] Call trace:
[ +0.000001] show_stack+0x24/0x40 (C)
[ +0.000006] __dump_stack+0x28/0x48
[ +0.000002] dump_stack_lvl+0x7c/0xb0
[ +0.000002] dump_stack+0x18/0x34
[ +0.000001] ubsan_epilogue+0x10/0x50
[ +0.000002] __ubsan_handle_load_invalid_value+0xc8/0xd0
[ +0.000003] locate_mem_hole_callback+0x28c/0x2a0
[ +0.000003] kexec_locate_mem_hole+0xf4/0x2f0
[ +0.000001] kexec_add_buffer+0xa8/0x178
[ +0.000002] image_load+0xf0/0x258
[ +0.000001] __arm64_sys_kexec_file_load+0x510/0x718
[ +0.000002] invoke_syscall+0x68/0xe8
[ +0.000001] el0_svc_common+0xb0/0xf8
[ +0.000002] do_el0_svc+0x28/0x48
[ +0.000001] el0_svc+0x40/0xe8
[ +0.000002] el0t_64_sync_handler+0x84/0x140
[ +0.000002] el0t_64_sync+0x1bc/0x1c0
To address this, initialise kexec_buf->random field properly.
Link: https://lkml.kernel.org/r/20251201105118.2786335-1-yeoreum.yun@arm.com
Fixes: bf454ec31add ("kexec_file: allow to place kexec_buf randomly")
Signed-off-by: Yeoreum Yun <yeoreum.yun(a)arm.com>
Suggested-by: Breno Leitao <leitao(a)debian.org>
Reviewed-by: Breno Leitao <leitao(a)debian.org>
Cc: Catalin Marinas <catalin.marinas(a)arm.com>
Cc: Coiby Xu <coxu(a)redhat.com>
Cc: levi.yun <yeoreum.yun(a)arm.com>
Cc: Marc Rutland <mark.rutland(a)arm.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
arch/arm64/kernel/kexec_image.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm64/kernel/kexec_image.c~arm64-kernel-initialize-missing-kexec_buf-random-field
+++ a/arch/arm64/kernel/kexec_image.c
@@ -41,7 +41,7 @@ static void *image_load(struct kimage *i
struct arm64_image_header *h;
u64 flags, value;
bool be_image, be_kernel;
- struct kexec_buf kbuf;
+ struct kexec_buf kbuf = {};
unsigned long text_offset, kernel_segment_number;
struct kexec_segment *kernel_segment;
int ret;
_
Patches currently in -mm which might be from yeoreum.yun(a)arm.com are
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 28ab2265e9422ccd81e4beafc0ace90f78de04c4
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010551-reawake-rimless-688e@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 28ab2265e9422ccd81e4beafc0ace90f78de04c4 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj(a)kernel.org>
Date: Sat, 1 Nov 2025 11:20:07 -0700
Subject: [PATCH] mm/damon/tests/core-kunit: handle alloc failres in
damon_test_new_filter()
damon_test_new_filter() is assuming all dynamic memory allocation in it
will succeed. Those are indeed likely in the real use cases since those
allocations are too small to fail, but theoretically those could fail. In
the case, inappropriate memory access can happen. Fix it by appropriately
cleanup pre-allocated memory and skip the execution of the remaining tests
in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-14-sj@kernel.org
Fixes: 2a158e956b98 ("mm/damon/core-test: add a test for damos_new_filter()")
Signed-off-by: SeongJae Park <sj(a)kernel.org>
Cc: Brendan Higgins <brendan.higgins(a)linux.dev>
Cc: David Gow <davidgow(a)google.com>
Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com>
Cc: <stable(a)vger.kernel.org> [6.6+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index b9bd69a57e62..03c7ac31db5c 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -505,6 +505,8 @@ static void damos_test_new_filter(struct kunit *test)
struct damos_filter *filter;
filter = damos_new_filter(DAMOS_FILTER_TYPE_ANON, true, false);
+ if (!filter)
+ kunit_skip(test, "filter alloc fail");
KUNIT_EXPECT_EQ(test, filter->type, DAMOS_FILTER_TYPE_ANON);
KUNIT_EXPECT_EQ(test, filter->matching, true);
KUNIT_EXPECT_PTR_EQ(test, filter->list.prev, &filter->list);
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 2b22d0fcc6320ba29b2122434c1d2f0785fb0a25
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010548-collage-trekker-25c4@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 2b22d0fcc6320ba29b2122434c1d2f0785fb0a25 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj(a)kernel.org>
Date: Sat, 1 Nov 2025 11:20:11 -0700
Subject: [PATCH] mm/damon/tests/vaddr-kunit: handle alloc failures on
damon_do_test_apply_three_regions()
damon_do_test_apply_three_regions() is assuming all dynamic memory
allocation in it will succeed. Those are indeed likely in the real use
cases since those allocations are too small to fail, but theoretically
those could fail. In the case, inappropriate memory access can happen.
Fix it by appropriately cleanup pre-allocated memory and skip the
execution of the remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-18-sj@kernel.org
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj(a)kernel.org>
Cc: Brendan Higgins <brendan.higgins(a)linux.dev>
Cc: David Gow <davidgow(a)google.com>
Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com>
Cc: <stable(a)vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
index fce38dd53cf8..484223f19545 100644
--- a/mm/damon/tests/vaddr-kunit.h
+++ b/mm/damon/tests/vaddr-kunit.h
@@ -136,8 +136,14 @@ static void damon_do_test_apply_three_regions(struct kunit *test,
int i;
t = damon_new_target();
+ if (!t)
+ kunit_skip(test, "target alloc fail");
for (i = 0; i < nr_regions / 2; i++) {
r = damon_new_region(regions[i * 2], regions[i * 2 + 1]);
+ if (!r) {
+ damon_destroy_target(t, NULL);
+ kunit_skip(test, "region alloc fail");
+ }
damon_add_region(r, t);
}
The patch titled
Subject: fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
fs-writeback-skip-as_no_data_integrity-mappings-in-wait_sb_inodes.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 various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Joanne Koong <joannelkoong(a)gmail.com>
Subject: fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes()
Date: Mon, 5 Jan 2026 13:17:27 -0800
Above the while() loop in wait_sb_inodes(), we document that we must wait
for all pages under writeback for data integrity. Consequently, if a
mapping, like fuse, traditionally does not have data integrity semantics,
there is no need to wait at all; we can simply skip these inodes.
This restores fuse back to prior behavior where syncs are no-ops. This
fixes a user regression where if a system is running a faulty fuse server
that does not reply to issued write requests, this causes wait_sb_inodes()
to wait forever.
Link: https://lkml.kernel.org/r/20260105211737.4105620-2-joannelkoong@gmail.com
Fixes: 0c58a97f919c ("fuse: remove tmp folio for writebacks and internal rb tree")
Signed-off-by: Joanne Koong <joannelkoong(a)gmail.com>
Reported-by: Athul Krishna <athul.krishna.kr(a)protonmail.com>
Reported-by: J. Neusch��fer <j.neuschaefer(a)gmx.net>
Reviewed-by: Bernd Schubert <bschubert(a)ddn.com>
Tested-by: J. Neusch��fer <j.neuschaefer(a)gmx.net>
Cc: Alexander Viro <viro(a)zeniv.linux.org.uk>
Cc: Bernd Schubert <bschubert(a)ddn.com>
Cc: Bonaccorso Salvatore <carnil(a)debian.org>
Cc: Christian Brauner <brauner(a)kernel.org>
Cc: David Hildenbrand <david(a)kernel.org>
Cc: Jan Kara <jack(a)suse.cz>
Cc: "Liam R. Howlett" <Liam.Howlett(a)oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com>
Cc: "Matthew Wilcox (Oracle)" <willy(a)infradead.org>
Cc: Michal Hocko <mhocko(a)suse.com>
Cc: Mike Rapoport <rppt(a)kernel.org>
Cc: Miklos Szeredi <miklos(a)szeredi.hu>
Cc: Suren Baghdasaryan <surenb(a)google.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
fs/fs-writeback.c | 7 ++++++-
fs/fuse/file.c | 4 +++-
include/linux/pagemap.h | 11 +++++++++++
3 files changed, 20 insertions(+), 2 deletions(-)
--- a/fs/fs-writeback.c~fs-writeback-skip-as_no_data_integrity-mappings-in-wait_sb_inodes
+++ a/fs/fs-writeback.c
@@ -2750,8 +2750,13 @@ static void wait_sb_inodes(struct super_
* The mapping can appear untagged while still on-list since we
* do not have the mapping lock. Skip it here, wb completion
* will remove it.
+ *
+ * If the mapping does not have data integrity semantics,
+ * there's no need to wait for the writeout to complete, as the
+ * mapping cannot guarantee that data is persistently stored.
*/
- if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
+ if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK) ||
+ mapping_no_data_integrity(mapping))
continue;
spin_unlock_irq(&sb->s_inode_wblist_lock);
--- a/fs/fuse/file.c~fs-writeback-skip-as_no_data_integrity-mappings-in-wait_sb_inodes
+++ a/fs/fuse/file.c
@@ -3200,8 +3200,10 @@ void fuse_init_file_inode(struct inode *
inode->i_fop = &fuse_file_operations;
inode->i_data.a_ops = &fuse_file_aops;
- if (fc->writeback_cache)
+ if (fc->writeback_cache) {
mapping_set_writeback_may_deadlock_on_reclaim(&inode->i_data);
+ mapping_set_no_data_integrity(&inode->i_data);
+ }
INIT_LIST_HEAD(&fi->write_files);
INIT_LIST_HEAD(&fi->queued_writes);
--- a/include/linux/pagemap.h~fs-writeback-skip-as_no_data_integrity-mappings-in-wait_sb_inodes
+++ a/include/linux/pagemap.h
@@ -210,6 +210,7 @@ enum mapping_flags {
AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM = 9,
AS_KERNEL_FILE = 10, /* mapping for a fake kernel file that shouldn't
account usage to user cgroups */
+ AS_NO_DATA_INTEGRITY = 11, /* no data integrity guarantees */
/* Bits 16-25 are used for FOLIO_ORDER */
AS_FOLIO_ORDER_BITS = 5,
AS_FOLIO_ORDER_MIN = 16,
@@ -345,6 +346,16 @@ static inline bool mapping_writeback_may
return test_bit(AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM, &mapping->flags);
}
+static inline void mapping_set_no_data_integrity(struct address_space *mapping)
+{
+ set_bit(AS_NO_DATA_INTEGRITY, &mapping->flags);
+}
+
+static inline bool mapping_no_data_integrity(const struct address_space *mapping)
+{
+ return test_bit(AS_NO_DATA_INTEGRITY, &mapping->flags);
+}
+
static inline gfp_t mapping_gfp_mask(const struct address_space *mapping)
{
return mapping->gfp_mask;
_
Patches currently in -mm which might be from joannelkoong(a)gmail.com are
fs-writeback-skip-as_no_data_integrity-mappings-in-wait_sb_inodes.patch
This patch adds a new mapping flag AS_NO_DATA_INTEGRITY which signifies that a
mapping does not have data integrity guarantees, and skips waiting on writeout
for these mappings in wait_sb_inodes(), as these mappings cannot guarantee
that data is persistently stored. This patch sets this flag on fuse mappings.
This fixes the userspace regression reported by Athul and J. upstream in
[1][2] where if there is a bug in a fuse server that causes the server to
never complete writeback, it will make wait_sb_inodes() wait forever.
Thanks,
Joanne
[1] https://lore.kernel.org/regressions/CAJnrk1ZjQ8W8NzojsvJPRXiv9TuYPNdj8Ye7=C…
[2] https://lore.kernel.org/linux-fsdevel/aT7JRqhUvZvfUQlV@eldamar.lan/
Changelog:
v2: https://lore.kernel.org/linux-fsdevel/20251215030043.1431306-1-joannelkoong…
* Add comments to commit message (David) and to wait_sb_inodes() (Andrew)
* Add Bernd's Reviewed-by and J's Tested-by
v1: https://lore.kernel.org/linux-mm/20251120184211.2379439-1-joannelkoong@gmai…
* Change AS_WRITEBACK_MAY_HANG to AS_NO_DATA_INTEGRITY and keep
AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM as is.
Joanne Koong (1):
fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes()
fs/fs-writeback.c | 7 ++++++-
fs/fuse/file.c | 4 +++-
include/linux/pagemap.h | 11 +++++++++++
3 files changed, 20 insertions(+), 2 deletions(-)
--
2.47.3
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x eded254cb69044bd4abde87394ea44909708d7c0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2026010533-capricorn-drown-ffcf@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From eded254cb69044bd4abde87394ea44909708d7c0 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj(a)kernel.org>
Date: Sat, 1 Nov 2025 11:20:02 -0700
Subject: [PATCH] mm/damon/tests/core-kunit: handle alloc failures on
damon_test_split_regions_of()
damon_test_split_regions_of() is assuming all dynamic memory allocation in
it will succeed. Those are indeed likely in the real use cases since
those allocations are too small to fail, but theoretically those could
fail. In the case, inappropriate memory access can happen. Fix it by
appropriately cleanup pre-allocated memory and skip the execution of the
remaining tests in the failure cases.
Link: https://lkml.kernel.org/r/20251101182021.74868-9-sj@kernel.org
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: SeongJae Park <sj(a)kernel.org>
Cc: Brendan Higgins <brendan.higgins(a)linux.dev>
Cc: David Gow <davidgow(a)google.com>
Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com>
Cc: <stable(a)vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 98f2a3de7cea..10618cdd188e 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -278,15 +278,35 @@ static void damon_test_split_regions_of(struct kunit *test)
struct damon_target *t;
struct damon_region *r;
+ if (!c)
+ kunit_skip("ctx alloc fail");
t = damon_new_target();
+ if (!t) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "target alloc fail");
+ }
r = damon_new_region(0, 22);
+ if (!r) {
+ damon_destroy_ctx(c);
+ damon_free_target(t);
+ kunit_skip(test, "region alloc fail");
+ }
damon_add_region(r, t);
damon_split_regions_of(t, 2, DAMON_MIN_REGION);
KUNIT_EXPECT_LE(test, damon_nr_regions(t), 2u);
damon_free_target(t);
t = damon_new_target();
+ if (!t) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "second target alloc fail");
+ }
r = damon_new_region(0, 220);
+ if (!r) {
+ damon_destroy_ctx(c);
+ damon_free_target(t);
+ kunit_skip(test, "second region alloc fail");
+ }
damon_add_region(r, t);
damon_split_regions_of(t, 4, DAMON_MIN_REGION);
KUNIT_EXPECT_LE(test, damon_nr_regions(t), 4u);