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The acpi_get_first_physical_node() function can return NULL, in which
case the get_device() function also returns NULL, but this value is
then dereferenced without checking,so add a check to prevent a crash.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 7b2f3eb492da ("ALSA: hda: cs35l41: Add support for CS35L41 in HDA systems")
Cc: stable(a)vger.kernel.org
Signed-off-by: Denis Arefev <arefev(a)swemel.ru>
---
sound/hda/codecs/side-codecs/cs35l41_hda.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/sound/hda/codecs/side-codecs/cs35l41_hda.c b/sound/hda/codecs/side-codecs/cs35l41_hda.c
index c0f2a3ff77a1..21e00055c0c4 100644
--- a/sound/hda/codecs/side-codecs/cs35l41_hda.c
+++ b/sound/hda/codecs/side-codecs/cs35l41_hda.c
@@ -1901,6 +1901,8 @@ static int cs35l41_hda_read_acpi(struct cs35l41_hda *cs35l41, const char *hid, i
cs35l41->dacpi = adev;
physdev = get_device(acpi_get_first_physical_node(adev));
+ if (!physdev)
+ return -ENODEV;
sub = acpi_get_subsystem_id(ACPI_HANDLE(physdev));
if (IS_ERR(sub))
--
2.43.0
The cntr_val_show() function was intended to print the values of all
counters using a loop. However, due to a buffer overwrite issue with
sprintf(), it effectively only displayed the value of the last counter.
The companion function, cntr_val_store(), allows users to modify a
specific counter selected by 'cntr_idx'. To maintain consistency
between read and write operations and to align with the ETM4x driver
behavior, modify cntr_val_show() to report only the value of the
currently selected counter.
This change removes the loop and the "counter %d:" prefix, printing
only the hexadecimal value. It also adopts sysfs_emit() for standard
sysfs output formatting.
Fixes: a939fc5a71ad ("coresight-etm: add CoreSight ETM/PTM driver")
Cc: stable(a)vger.kernel.org
Signed-off-by: Kuan-Wei Chiu <visitorckw(a)gmail.com>
---
Build test only.
Changes in v3:
- Switch format specifier to %#x to include the 0x prefix.
- Add Cc stable
v2: https://lore.kernel.org/lkml/20251201095228.1905489-1-visitorckw@gmail.com/
.../hwtracing/coresight/coresight-etm3x-sysfs.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
index 762109307b86..b3c67e96a82a 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
@@ -717,26 +717,19 @@ static DEVICE_ATTR_RW(cntr_rld_event);
static ssize_t cntr_val_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- int i, ret = 0;
u32 val;
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
struct etm_config *config = &drvdata->config;
if (!coresight_get_mode(drvdata->csdev)) {
spin_lock(&drvdata->spinlock);
- for (i = 0; i < drvdata->nr_cntr; i++)
- ret += sprintf(buf, "counter %d: %x\n",
- i, config->cntr_val[i]);
+ val = config->cntr_val[config->cntr_idx];
spin_unlock(&drvdata->spinlock);
- return ret;
- }
-
- for (i = 0; i < drvdata->nr_cntr; i++) {
- val = etm_readl(drvdata, ETMCNTVRn(i));
- ret += sprintf(buf, "counter %d: %x\n", i, val);
+ } else {
+ val = etm_readl(drvdata, ETMCNTVRn(config->cntr_idx));
}
- return ret;
+ return sysfs_emit(buf, "%#x\n", val);
}
static ssize_t cntr_val_store(struct device *dev,
--
2.52.0.158.g65b55ccf14-goog
A memory leak exists in the handling of repeat mode damon_call_control
objects by kdamond_call(). While damon_call() correctly allows multiple
repeat mode objects (with ->repeat set to true) to be added to the
per-context list, kdamond_call() incorrectly processes them.
The function moves all repeat mode objects from the context's list to a
temporary list (repeat_controls). However, it only moves the first
object back to the context's list for future calls, leaving the
remaining objects on the temporary list where they are abandoned and
leaked.
This patch fixes the leak by ensuring all repeat mode objects are
properly re-added to the context's list.
Fixes: 43df7676e550 ("mm/damon/core: introduce repeat mode damon_call()")
Signed-off-by: Enze Li <lienze(a)kylinos.cn>
Cc: <stable(a)vger.kernel.org> # 6.17.x
---
mm/damon/core.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 109b050c795a..66b5bae44f22 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2526,13 +2526,19 @@ static void kdamond_call(struct damon_ctx *ctx, bool cancel)
list_add(&control->list, &repeat_controls);
}
}
- control = list_first_entry_or_null(&repeat_controls,
- struct damon_call_control, list);
- if (!control || cancel)
- return;
- mutex_lock(&ctx->call_controls_lock);
- list_add_tail(&control->list, &ctx->call_controls);
- mutex_unlock(&ctx->call_controls_lock);
+ while (true) {
+ control = list_first_entry_or_null(&repeat_controls,
+ struct damon_call_control, list);
+ if (!control)
+ break;
+ /* Unlink from the repeate_controls list. */
+ list_del(&control->list);
+ if (cancel)
+ continue;
+ mutex_lock(&ctx->call_controls_lock);
+ list_add(&control->list, &ctx->call_controls);
+ mutex_unlock(&ctx->call_controls_lock);
+ }
}
/* Returns negative error code if it's not activated but should return */
base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449
--
2.52.0
Hello Enze,
First of all, thank you for sharing this patch!
On Tue, 2 Dec 2025 10:14:07 +0800 Enze Li <lienze(a)kylinos.cn> wrote:
> The current implementation only supports repeated calls to a single
> damon_call_control request per context.
I understand "repeated calls to a single damon_call_control" means "single
damon_call_control object having ->repeat set as true". Let me call it "repeat
mode damon_call_control object".
This is not an intentionally designed limitation but a bug. damon_call()
allows callers adding multiple repeat mode damon_call_control objects per
context. Technically, it adds any requested damon_call_control object to the
per-context linked list, regardless of the number of repeat mode objects on the
list. But, the consumer of the damon_call_control objects list,
kdamond_call(), moves the repeat mode objects from the per-context list to a
temporal list (repeat_controls), and then move only the first repeat mode entry
from the temporal list to the per-context list.
If there were multiple repeat mode objects in the per-context list, what
happens to the remaining repeat mode damon_call_control objects on the temporal
list? Nothing. As a result, the memory for the objects are leaked.
Definitely this is a bug.
Luckily there is no such multiple repeat mode damon_call() requests, so no
upstream kernel user is exposed to the memory leak bug in real. But the bug is
a bug. We should fix this.
> This limitation introduces
> inefficiencies for scenarios that require registering multiple deferred
> operations.
I'm not very convinced with the above reasoning because 1. it is not a matter
of inefficiency but a clear memory leak bug. 2. there is no damon_call()
callers that want to have multiple deferred operations with high efficiency, at
the moment. In my opinion, the above sentence is better to be just dropped.
>
> This patch modifies the implementation of kdamond_call() to support
> repeated calls to multiple damon_call_control requests.
This change is rquired for fixing the bug, though.
> To demonstrate
> the effect of this change, I made minor modifications to
> samples/damon/prcl.c by adding a new request alongside the original
> damon_call_control request and performed comparative tests.
>
> Before applying the patch, I observed,
>
> [ 381.661821] damon_sample_prcl: start
> [ 381.668199] damon_sample_prcl: repeat_call_v2
> [ 381.668208] damon_sample_prcl: repeat_call
> [ 381.668211] damon_sample_prcl: wss: 0
> [ 381.675194] damon_sample_prcl: repeat_call
> [ 381.675202] damon_sample_prcl: wss: 0
>
> after applying the patch, I saw,
>
> [ 61.750723] damon_sample_prcl: start
> [ 61.757104] damon_sample_prcl: repeat_call_v2
> [ 61.757106] damon_sample_prcl: repeat_call
> [ 61.757107] damon_sample_prcl: wss: 0
> [ 61.763067] damon_sample_prcl: repeat_call_v2
> [ 61.763069] damon_sample_prcl: repeat_call
> [ 61.763070] damon_sample_prcl: wss: 0
>
> Signed-off-by: Enze Li <lienze(a)kylinos.cn>
Assuming we agree on the fact this is a fix of the bug, I think we should add
below tags.
Fixes: 43df7676e550 ("mm/damon/core: introduce repeat mode damon_call()")
Cc: <stable(a)vger.kernel.org> # 6.17.x
> ---
> mm/damon/core.c | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 109b050c795a..66b5bae44f22 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -2526,13 +2526,19 @@ static void kdamond_call(struct damon_ctx *ctx, bool cancel)
> list_add(&control->list, &repeat_controls);
> }
> }
> - control = list_first_entry_or_null(&repeat_controls,
> - struct damon_call_control, list);
> - if (!control || cancel)
> - return;
> - mutex_lock(&ctx->call_controls_lock);
> - list_add_tail(&control->list, &ctx->call_controls);
> - mutex_unlock(&ctx->call_controls_lock);
> + while (true) {
> + control = list_first_entry_or_null(&repeat_controls,
> + struct damon_call_control, list);
> + if (!control)
> + break;
> + /* Unlink from the repeate_controls list. */
> + list_del(&control->list);
> + if (cancel)
> + continue;
> + mutex_lock(&ctx->call_controls_lock);
> + list_add(&control->list, &ctx->call_controls);
> + mutex_unlock(&ctx->call_controls_lock);
> + }
This looks good enough to fix the bug.
Could you please resend this patch after rewording the commit message as
appripriate for the bug fix, adding points I listed above?
Again, thank you for letting us find this bug.
Thanks,
SJ
[...]
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 cff47b9e39a6abf03dde5f4f156f841b0c54bba0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025120102-geranium-elevator-ca86@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From cff47b9e39a6abf03dde5f4f156f841b0c54bba0 Mon Sep 17 00:00:00 2001
From: Wei Yang <richard.weiyang(a)gmail.com>
Date: Wed, 19 Nov 2025 23:53:02 +0000
Subject: [PATCH] mm/huge_memory: fix NULL pointer deference when splitting
folio
Commit c010d47f107f ("mm: thp: split huge page to any lower order pages")
introduced an early check on the folio's order via mapping->flags before
proceeding with the split work.
This check introduced a bug: for shmem folios in the swap cache and
truncated folios, the mapping pointer can be NULL. Accessing
mapping->flags in this state leads directly to a NULL pointer dereference.
This commit fixes the issue by moving the check for mapping != NULL before
any attempt to access mapping->flags.
Link: https://lkml.kernel.org/r/20251119235302.24773-1-richard.weiyang@gmail.com
Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages")
Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com>
Reviewed-by: Zi Yan <ziy(a)nvidia.com>
Acked-by: David Hildenbrand (Red Hat) <david(a)kernel.org>
Reviewed-by: Baolin Wang <baolin.wang(a)linux.alibaba.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2f2a521e5d68..6cba1cb14b23 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3619,6 +3619,16 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
if (folio != page_folio(split_at) || folio != page_folio(lock_at))
return -EINVAL;
+ /*
+ * Folios that just got truncated cannot get split. Signal to the
+ * caller that there was a race.
+ *
+ * TODO: this will also currently refuse shmem folios that are in the
+ * swapcache.
+ */
+ if (!is_anon && !folio->mapping)
+ return -EBUSY;
+
if (new_order >= folio_order(folio))
return -EINVAL;
@@ -3659,18 +3669,6 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
gfp_t gfp;
mapping = folio->mapping;
-
- /* Truncated ? */
- /*
- * TODO: add support for large shmem folio in swap cache.
- * When shmem is in swap cache, mapping is NULL and
- * folio_test_swapcache() is true.
- */
- if (!mapping) {
- ret = -EBUSY;
- goto out;
- }
-
min_order = mapping_min_folio_order(folio->mapping);
if (new_order < min_order) {
ret = -EINVAL;