The patch below does not apply to the 5.15-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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 98c6d259319ecf6e8d027abd3f14b81324b8c0ad
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025092152-bobtail-scarring-ffff@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 98c6d259319ecf6e8d027abd3f14b81324b8c0ad Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd(a)google.com>
Date: Mon, 8 Sep 2025 15:15:03 -0700
Subject: [PATCH] mm/gup: check ref_count instead of lru before migration
Patch series "mm: better GUP pin lru_add_drain_all()", v2.
Series of lru_add_drain_all()-related patches, arising from recent mm/gup
migration report from Will Deacon.
This patch (of 5):
Will Deacon reports:-
When taking a longterm GUP pin via pin_user_pages(),
__gup_longterm_locked() tries to migrate target folios that should not be
longterm pinned, for example because they reside in a CMA region or
movable zone. This is done by first pinning all of the target folios
anyway, collecting all of the longterm-unpinnable target folios into a
list, dropping the pins that were just taken and finally handing the list
off to migrate_pages() for the actual migration.
It is critically important that no unexpected references are held on the
folios being migrated, otherwise the migration will fail and
pin_user_pages() will return -ENOMEM to its caller. Unfortunately, it is
relatively easy to observe migration failures when running pKVM (which
uses pin_user_pages() on crosvm's virtual address space to resolve stage-2
page faults from the guest) on a 6.15-based Pixel 6 device and this
results in the VM terminating prematurely.
In the failure case, 'crosvm' has called mlock(MLOCK_ONFAULT) on its
mapping of guest memory prior to the pinning. Subsequently, when
pin_user_pages() walks the page-table, the relevant 'pte' is not present
and so the faulting logic allocates a new folio, mlocks it with
mlock_folio() and maps it in the page-table.
Since commit 2fbb0c10d1e8 ("mm/munlock: mlock_page() munlock_page() batch
by pagevec"), mlock/munlock operations on a folio (formerly page), are
deferred. For example, mlock_folio() takes an additional reference on the
target folio before placing it into a per-cpu 'folio_batch' for later
processing by mlock_folio_batch(), which drops the refcount once the
operation is complete. Processing of the batches is coupled with the LRU
batch logic and can be forcefully drained with lru_add_drain_all() but as
long as a folio remains unprocessed on the batch, its refcount will be
elevated.
This deferred batching therefore interacts poorly with the pKVM pinning
scenario as we can find ourselves in a situation where the migration code
fails to migrate a folio due to the elevated refcount from the pending
mlock operation.
Hugh Dickins adds:-
!folio_test_lru() has never been a very reliable way to tell if an
lru_add_drain_all() is worth calling, to remove LRU cache references to
make the folio migratable: the LRU flag may be set even while the folio is
held with an extra reference in a per-CPU LRU cache.
5.18 commit 2fbb0c10d1e8 may have made it more unreliable. Then 6.11
commit 33dfe9204f29 ("mm/gup: clear the LRU flag of a page before adding
to LRU batch") tried to make it reliable, by moving LRU flag clearing; but
missed the mlock/munlock batches, so still unreliable as reported.
And it turns out to be difficult to extend 33dfe9204f29's LRU flag
clearing to the mlock/munlock batches: if they do benefit from batching,
mlock/munlock cannot be so effective when easily suppressed while !LRU.
Instead, switch to an expected ref_count check, which was more reliable
all along: some more false positives (unhelpful drains) than before, and
never a guarantee that the folio will prove migratable, but better.
Note on PG_private_2: ceph and nfs are still using the deprecated
PG_private_2 flag, with the aid of netfs and filemap support functions.
Although it is consistently matched by an increment of folio ref_count,
folio_expected_ref_count() intentionally does not recognize it, and ceph
folio migration currently depends on that for PG_private_2 folios to be
rejected. New references to the deprecated flag are discouraged, so do
not add it into the collect_longterm_unpinnable_folios() calculation: but
longterm pinning of transiently PG_private_2 ceph and nfs folios (an
uncommon case) may invoke a redundant lru_add_drain_all(). And this makes
easy the backport to earlier releases: up to and including 6.12, btrfs
also used PG_private_2, but without a ref_count increment.
Note for stable backports: requires 6.16 commit 86ebd50224c0 ("mm:
add folio_expected_ref_count() for reference count calculation").
Link: https://lkml.kernel.org/r/41395944-b0e3-c3ac-d648-8ddd70451d28@google.com
Link: https://lkml.kernel.org/r/bd1f314a-fca1-8f19-cac0-b936c9614557@google.com
Fixes: 9a4e9f3b2d73 ("mm: update get_user_pages_longterm to migrate pages allocated from CMA region")
Signed-off-by: Hugh Dickins <hughd(a)google.com>
Reported-by: Will Deacon <will(a)kernel.org>
Closes: https://lore.kernel.org/linux-mm/20250815101858.24352-1-will@kernel.org/
Acked-by: Kiryl Shutsemau <kas(a)kernel.org>
Acked-by: David Hildenbrand <david(a)redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar(a)kernel.org>
Cc: Axel Rasmussen <axelrasmussen(a)google.com>
Cc: Chris Li <chrisl(a)kernel.org>
Cc: Christoph Hellwig <hch(a)infradead.org>
Cc: Jason Gunthorpe <jgg(a)ziepe.ca>
Cc: Johannes Weiner <hannes(a)cmpxchg.org>
Cc: John Hubbard <jhubbard(a)nvidia.com>
Cc: Keir Fraser <keirf(a)google.com>
Cc: Konstantin Khlebnikov <koct9i(a)gmail.com>
Cc: Li Zhe <lizhe.67(a)bytedance.com>
Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org>
Cc: Peter Xu <peterx(a)redhat.com>
Cc: Rik van Riel <riel(a)surriel.com>
Cc: Shivank Garg <shivankg(a)amd.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: Wei Xu <weixugc(a)google.com>
Cc: yangge <yangge1116(a)126.com>
Cc: Yuanchu Xie <yuanchu(a)google.com>
Cc: Yu Zhao <yuzhao(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/gup.c b/mm/gup.c
index adffe663594d..82aec6443c0a 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2307,7 +2307,8 @@ static unsigned long collect_longterm_unpinnable_folios(
continue;
}
- if (!folio_test_lru(folio) && drain_allow) {
+ if (drain_allow && folio_ref_count(folio) !=
+ folio_expected_ref_count(folio) + 1) {
lru_add_drain_all();
drain_allow = false;
}
wcd934x_codec_parse_data() contains a device reference count leak in
of_slim_get_device() where device_find_child() increases the reference
count of the device but this reference is not properly decreased in
the success path. Add put_device() in wcd934x_codec_parse_data(),
which ensures that the reference count of the device is correctly
managed.
Calling path: of_slim_get_device() -> of_find_slim_device() ->
device_find_child(). As comment of device_find_child() says, 'NOTE:
you will need to drop the reference with put_device() after use.'.
Found by code review.
Cc: stable(a)vger.kernel.org
Fixes: a61f3b4f476e ("ASoC: wcd934x: add support to wcd9340/wcd9341 codec")
Signed-off-by: Ma Ke <make24(a)iscas.ac.cn>
---
sound/soc/codecs/wcd934x.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/sound/soc/codecs/wcd934x.c b/sound/soc/codecs/wcd934x.c
index 1bb7e1dc7e6b..9ffa65329934 100644
--- a/sound/soc/codecs/wcd934x.c
+++ b/sound/soc/codecs/wcd934x.c
@@ -5849,10 +5849,13 @@ static int wcd934x_codec_parse_data(struct wcd934x_codec *wcd)
slim_get_logical_addr(wcd->sidev);
wcd->if_regmap = regmap_init_slimbus(wcd->sidev,
&wcd934x_ifc_regmap_config);
- if (IS_ERR(wcd->if_regmap))
+ if (IS_ERR(wcd->if_regmap)) {
+ put_device(&wcd->sidev->dev);
return dev_err_probe(dev, PTR_ERR(wcd->if_regmap),
"Failed to allocate ifc register map\n");
+ }
+ put_device(&wcd->sidev->dev);
of_property_read_u32(dev->parent->of_node, "qcom,dmic-sample-rate",
&wcd->dmic_sample_rate);
--
2.17.1
When do_task() exhausts its iteration budget (!ret), it sets the state
to TASK_STATE_IDLE to reschedule, without a secondary check on the
current task->state. This can overwrite the TASK_STATE_DRAINING state
set by a concurrent call to rxe_cleanup_task() or rxe_disable_task().
While state changes are protected by a spinlock, both rxe_cleanup_task()
and rxe_disable_task() release the lock while waiting for the task to
finish draining in the while(!is_done(task)) loop. The race occurs if
do_task() hits its iteration limit and acquires the lock in this window.
The cleanup logic may then proceed while the task incorrectly
reschedules itself, leading to a potential use-after-free.
This bug was introduced during the migration from tasklets to workqueues,
where the special handling for the draining case was lost.
Fix this by restoring the original pre-migration behavior. If the state is
TASK_STATE_DRAINING when iterations are exhausted, set cont to 1 to
force a new loop iteration. This allows the task to finish its work, so
that a subsequent iteration can reach the switch statement and correctly
transition the state to TASK_STATE_DRAINED, stopping the task as intended.
Fixes: 9b4b7c1f9f54 ("RDMA/rxe: Add workqueue support for rxe tasks")
Cc: stable(a)vger.kernel.org
Reviewed-by: Zhu Yanjun <yanjun.zhu(a)linux.dev>
Signed-off-by: Gui-Dong Han <hanguidong02(a)gmail.com>
---
v2:
* Rewrite commit message for clarity. Thanks to Zhu Yanjun for the review.
---
drivers/infiniband/sw/rxe/rxe_task.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_task.c b/drivers/infiniband/sw/rxe/rxe_task.c
index 6f8f353e9583..f522820b950c 100644
--- a/drivers/infiniband/sw/rxe/rxe_task.c
+++ b/drivers/infiniband/sw/rxe/rxe_task.c
@@ -132,8 +132,12 @@ static void do_task(struct rxe_task *task)
* yield the cpu and reschedule the task
*/
if (!ret) {
- task->state = TASK_STATE_IDLE;
- resched = 1;
+ if (task->state != TASK_STATE_DRAINING) {
+ task->state = TASK_STATE_IDLE;
+ resched = 1;
+ } else {
+ cont = 1;
+ }
goto exit;
}
--
2.25.1
To: linux-kernel(a)vger.kernel.org
Cc: Paul Walmsley <paul.walmsley(a)sifive.com>
Cc: Samuel Holland <samuel.holland(a)sifive.com>
Cc: stable(a)vger.kernel.org
Cc: linux-riscv(a)lists.infradead.org
Cc: Thomas Gleixner <tglx(a)linutronix.de>
According to the PLIC specification[1], global interrupt sources are
assigned small unsigned integer identifiers beginning at the value 1.
An interrupt ID of 0 is reserved to mean "no interrupt".
The current plic_irq_resume() and plic_irq_suspend() functions incorrectly
starts the loop from index 0, which could access the reserved interrupt ID
0 register space.
This fix changes the loop to start from index 1, skipping the reserved
interrupt ID 0 as per the PLIC specification.
This prevents potential undefined behavior when accessing the reserved
register space during suspend/resume cycles.
Fixes: e80f0b6a2cf3 ("irqchip/irq-sifive-plic: Add syscore callbacks for hibernation")
Co-developed-by: Jia Wang <wangjia(a)ultrarisc.com>
Signed-off-by: Jia Wang <wangjia(a)ultrarisc.com>
Signed-off-by: Lucas Zampieri <lzampier(a)redhat.com>
[1] https://github.com/riscv/riscv-plic-spec/releases/tag/1.0.0
---
drivers/irqchip/irq-sifive-plic.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index bf69a4802b71..1c2b4d2575ac 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -252,7 +252,7 @@ static int plic_irq_suspend(void)
priv = per_cpu_ptr(&plic_handlers, smp_processor_id())->priv;
- for (i = 0; i < priv->nr_irqs; i++) {
+ for (i = 1; i < priv->nr_irqs; i++) {
__assign_bit(i, priv->prio_save,
readl(priv->regs + PRIORITY_BASE + i * PRIORITY_PER_ID));
}
@@ -283,7 +283,7 @@ static void plic_irq_resume(void)
priv = per_cpu_ptr(&plic_handlers, smp_processor_id())->priv;
- for (i = 0; i < priv->nr_irqs; i++) {
+ for (i = 1; i < priv->nr_irqs; i++) {
index = BIT_WORD(i);
writel((priv->prio_save[index] & BIT_MASK(i)) ? 1 : 0,
priv->regs + PRIORITY_BASE + i * PRIORITY_PER_ID);
--
2.51.0
In register_shm_helper(), fix incorrect error handling for a call to
iov_iter_extract_pages(). A case is missing for when
iov_iter_extract_pages() only got some pages and return a number larger
than 0, but not the requested amount.
This fixes a possible NULL pointer dereference following a bad input from
ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped.
Cc: stable(a)vger.kernel.org
Reported-by: Masami Ichikawa <masami256(a)gmail.com>
Closes: https://lore.kernel.org/op-tee/CACOXgS-Bo2W72Nj1_44c7bntyNYOavnTjJAvUbEiQfq…
Fixes: 7bdee4157591 ("tee: Use iov_iter to better support shared buffer registration")
Signed-off-by: Jens Wiklander <jens.wiklander(a)linaro.org>
---
drivers/tee/tee_shm.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index daf6e5cfd59a..6ed7d030f4ed 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -316,7 +316,16 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags,
len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0,
&off);
- if (unlikely(len <= 0)) {
+ if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) {
+ if (len > 0) {
+ /*
+ * If we only got a few pages, update to release
+ * the correct amount below.
+ */
+ shm->num_pages = len / PAGE_SIZE;
+ ret = ERR_PTR(-ENOMEM);
+ goto err_put_shm_pages;
+ }
ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM);
goto err_free_shm_pages;
}
--
2.43.0
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Albinayah Trading