The patch below does not apply to the 5.4-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-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101635-twitch-preoccupy-ad1d@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso(a)mit.edu>
Date: Tue, 16 Sep 2025 23:22:47 -0400
Subject: [PATCH] ext4: avoid potential buffer over-read in
parse_apply_sb_mount_options()
Unlike other strings in the ext4 superblock, we rely on tune2fs to
make sure s_mount_opts is NUL terminated. Harden
parse_apply_sb_mount_options() by treating s_mount_opts as a potential
__nonstring.
Cc: stable(a)vger.kernel.org
Fixes: 8b67f04ab9de ("ext4: Add mount options in superblock")
Reviewed-by: Jan Kara <jack(a)suse.cz>
Reviewed-by: Darrick J. Wong <djwong(a)kernel.org>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
Message-ID: <20250916-tune2fs-v2-1-d594dc7486f0(a)mit.edu>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d26e5c0731e5..488f4c281a3f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2469,7 +2469,7 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
struct ext4_fs_context *m_ctx)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
- char *s_mount_opts = NULL;
+ char s_mount_opts[65];
struct ext4_fs_context *s_ctx = NULL;
struct fs_context *fc = NULL;
int ret = -ENOMEM;
@@ -2477,15 +2477,11 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
if (!sbi->s_es->s_mount_opts[0])
return 0;
- s_mount_opts = kstrndup(sbi->s_es->s_mount_opts,
- sizeof(sbi->s_es->s_mount_opts),
- GFP_KERNEL);
- if (!s_mount_opts)
- return ret;
+ strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts);
fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL);
if (!fc)
- goto out_free;
+ return -ENOMEM;
s_ctx = kzalloc(sizeof(struct ext4_fs_context), GFP_KERNEL);
if (!s_ctx)
@@ -2517,11 +2513,8 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
ret = 0;
out_free:
- if (fc) {
- ext4_fc_free(fc);
- kfree(fc);
- }
- kfree(s_mount_opts);
+ ext4_fc_free(fc);
+ kfree(fc);
return ret;
}
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 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101634-energize-tartness-d7b6@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso(a)mit.edu>
Date: Tue, 16 Sep 2025 23:22:47 -0400
Subject: [PATCH] ext4: avoid potential buffer over-read in
parse_apply_sb_mount_options()
Unlike other strings in the ext4 superblock, we rely on tune2fs to
make sure s_mount_opts is NUL terminated. Harden
parse_apply_sb_mount_options() by treating s_mount_opts as a potential
__nonstring.
Cc: stable(a)vger.kernel.org
Fixes: 8b67f04ab9de ("ext4: Add mount options in superblock")
Reviewed-by: Jan Kara <jack(a)suse.cz>
Reviewed-by: Darrick J. Wong <djwong(a)kernel.org>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
Message-ID: <20250916-tune2fs-v2-1-d594dc7486f0(a)mit.edu>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d26e5c0731e5..488f4c281a3f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2469,7 +2469,7 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
struct ext4_fs_context *m_ctx)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
- char *s_mount_opts = NULL;
+ char s_mount_opts[65];
struct ext4_fs_context *s_ctx = NULL;
struct fs_context *fc = NULL;
int ret = -ENOMEM;
@@ -2477,15 +2477,11 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
if (!sbi->s_es->s_mount_opts[0])
return 0;
- s_mount_opts = kstrndup(sbi->s_es->s_mount_opts,
- sizeof(sbi->s_es->s_mount_opts),
- GFP_KERNEL);
- if (!s_mount_opts)
- return ret;
+ strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts);
fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL);
if (!fc)
- goto out_free;
+ return -ENOMEM;
s_ctx = kzalloc(sizeof(struct ext4_fs_context), GFP_KERNEL);
if (!s_ctx)
@@ -2517,11 +2513,8 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
ret = 0;
out_free:
- if (fc) {
- ext4_fc_free(fc);
- kfree(fc);
- }
- kfree(s_mount_opts);
+ ext4_fc_free(fc);
+ kfree(fc);
return ret;
}
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 399dbcadc01ebf0035f325eaa8c264f8b5cd0a14
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101635-disaster-pasture-f32d@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 399dbcadc01ebf0035f325eaa8c264f8b5cd0a14 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki(a)intel.com>
Date: Sun, 28 Sep 2025 12:18:29 +0200
Subject: [PATCH] ACPI: battery: Add synchronization between interface updates
There is no synchronization between different code paths in the ACPI
battery driver that update its sysfs interface or its power supply
class device interface. In some cases this results to functional
failures due to race conditions.
One example of this is when two ACPI notifications:
- ACPI_BATTERY_NOTIFY_STATUS (0x80)
- ACPI_BATTERY_NOTIFY_INFO (0x81)
are triggered (by the platform firmware) in a row with a little delay
in between after removing and reinserting a laptop battery. Both
notifications cause acpi_battery_update() to be called and if the delay
between them is sufficiently small, sysfs_add_battery() can be re-entered
before battery->bat is set which leads to a duplicate sysfs entry error:
sysfs: cannot create duplicate filename '/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0A:00/power_supply/BAT1'
CPU: 1 UID: 0 PID: 185 Comm: kworker/1:4 Kdump: loaded Not tainted 6.12.38+deb13-amd64 #1 Debian 6.12.38-1
Hardware name: Gateway NV44 /SJV40-MV , BIOS V1.3121 04/08/2009
Workqueue: kacpi_notify acpi_os_execute_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x5d/0x80
sysfs_warn_dup.cold+0x17/0x23
sysfs_create_dir_ns+0xce/0xe0
kobject_add_internal+0xba/0x250
kobject_add+0x96/0xc0
? get_device_parent+0xde/0x1e0
device_add+0xe2/0x870
__power_supply_register.part.0+0x20f/0x3f0
? wake_up_q+0x4e/0x90
sysfs_add_battery+0xa4/0x1d0 [battery]
acpi_battery_update+0x19e/0x290 [battery]
acpi_battery_notify+0x50/0x120 [battery]
acpi_ev_notify_dispatch+0x49/0x70
acpi_os_execute_deferred+0x1a/0x30
process_one_work+0x177/0x330
worker_thread+0x251/0x390
? __pfx_worker_thread+0x10/0x10
kthread+0xd2/0x100
? __pfx_kthread+0x10/0x10
ret_from_fork+0x34/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
kobject: kobject_add_internal failed for BAT1 with -EEXIST, don't try to register things with the same name in the same directory.
There are also other scenarios in which analogous issues may occur.
Address this by using a common lock in all of the code paths leading
to updates of driver interfaces: ACPI Notify () handler, system resume
callback and post-resume notification, device addition and removal.
This new lock replaces sysfs_lock that has been used only in
sysfs_remove_battery() which now is going to be always called under
the new lock, so it doesn't need any internal locking any more.
Fixes: 10666251554c ("ACPI: battery: Install Notify() handler directly")
Closes: https://lore.kernel.org/linux-acpi/20250910142653.313360-1-luogf2025@163.co…
Reported-by: GuangFei Luo <luogf2025(a)163.com>
Tested-by: GuangFei Luo <luogf2025(a)163.com>
Cc: 6.6+ <stable(a)vger.kernel.org> # 6.6+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com>
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 6905b56bf3e4..67b76492c839 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -92,7 +92,7 @@ enum {
struct acpi_battery {
struct mutex lock;
- struct mutex sysfs_lock;
+ struct mutex update_lock;
struct power_supply *bat;
struct power_supply_desc bat_desc;
struct acpi_device *device;
@@ -904,15 +904,12 @@ static int sysfs_add_battery(struct acpi_battery *battery)
static void sysfs_remove_battery(struct acpi_battery *battery)
{
- mutex_lock(&battery->sysfs_lock);
- if (!battery->bat) {
- mutex_unlock(&battery->sysfs_lock);
+ if (!battery->bat)
return;
- }
+
battery_hook_remove_battery(battery);
power_supply_unregister(battery->bat);
battery->bat = NULL;
- mutex_unlock(&battery->sysfs_lock);
}
static void find_battery(const struct dmi_header *dm, void *private)
@@ -1072,6 +1069,9 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
if (!battery)
return;
+
+ guard(mutex)(&battery->update_lock);
+
old = battery->bat;
/*
* On Acer Aspire V5-573G notifications are sometimes triggered too
@@ -1094,21 +1094,22 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
}
static int battery_notify(struct notifier_block *nb,
- unsigned long mode, void *_unused)
+ unsigned long mode, void *_unused)
{
struct acpi_battery *battery = container_of(nb, struct acpi_battery,
pm_nb);
- int result;
- switch (mode) {
- case PM_POST_HIBERNATION:
- case PM_POST_SUSPEND:
+ if (mode == PM_POST_SUSPEND || mode == PM_POST_HIBERNATION) {
+ guard(mutex)(&battery->update_lock);
+
if (!acpi_battery_present(battery))
return 0;
if (battery->bat) {
acpi_battery_refresh(battery);
} else {
+ int result;
+
result = acpi_battery_get_info(battery);
if (result)
return result;
@@ -1120,7 +1121,6 @@ static int battery_notify(struct notifier_block *nb,
acpi_battery_init_alarm(battery);
acpi_battery_get_state(battery);
- break;
}
return 0;
@@ -1198,6 +1198,8 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
{
int retry, ret;
+ guard(mutex)(&battery->update_lock);
+
for (retry = 5; retry; retry--) {
ret = acpi_battery_update(battery, false);
if (!ret)
@@ -1208,6 +1210,13 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
return ret;
}
+static void sysfs_battery_cleanup(struct acpi_battery *battery)
+{
+ guard(mutex)(&battery->update_lock);
+
+ sysfs_remove_battery(battery);
+}
+
static int acpi_battery_add(struct acpi_device *device)
{
int result = 0;
@@ -1230,7 +1239,7 @@ static int acpi_battery_add(struct acpi_device *device)
if (result)
return result;
- result = devm_mutex_init(&device->dev, &battery->sysfs_lock);
+ result = devm_mutex_init(&device->dev, &battery->update_lock);
if (result)
return result;
@@ -1262,7 +1271,7 @@ static int acpi_battery_add(struct acpi_device *device)
device_init_wakeup(&device->dev, 0);
unregister_pm_notifier(&battery->pm_nb);
fail:
- sysfs_remove_battery(battery);
+ sysfs_battery_cleanup(battery);
return result;
}
@@ -1281,6 +1290,9 @@ static void acpi_battery_remove(struct acpi_device *device)
device_init_wakeup(&device->dev, 0);
unregister_pm_notifier(&battery->pm_nb);
+
+ guard(mutex)(&battery->update_lock);
+
sysfs_remove_battery(battery);
}
@@ -1297,6 +1309,9 @@ static int acpi_battery_resume(struct device *dev)
return -EINVAL;
battery->update_time = 0;
+
+ guard(mutex)(&battery->update_lock);
+
acpi_battery_update(battery, true);
return 0;
}
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 399dbcadc01ebf0035f325eaa8c264f8b5cd0a14
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101634-factsheet-preplan-069e@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 399dbcadc01ebf0035f325eaa8c264f8b5cd0a14 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki(a)intel.com>
Date: Sun, 28 Sep 2025 12:18:29 +0200
Subject: [PATCH] ACPI: battery: Add synchronization between interface updates
There is no synchronization between different code paths in the ACPI
battery driver that update its sysfs interface or its power supply
class device interface. In some cases this results to functional
failures due to race conditions.
One example of this is when two ACPI notifications:
- ACPI_BATTERY_NOTIFY_STATUS (0x80)
- ACPI_BATTERY_NOTIFY_INFO (0x81)
are triggered (by the platform firmware) in a row with a little delay
in between after removing and reinserting a laptop battery. Both
notifications cause acpi_battery_update() to be called and if the delay
between them is sufficiently small, sysfs_add_battery() can be re-entered
before battery->bat is set which leads to a duplicate sysfs entry error:
sysfs: cannot create duplicate filename '/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0A:00/power_supply/BAT1'
CPU: 1 UID: 0 PID: 185 Comm: kworker/1:4 Kdump: loaded Not tainted 6.12.38+deb13-amd64 #1 Debian 6.12.38-1
Hardware name: Gateway NV44 /SJV40-MV , BIOS V1.3121 04/08/2009
Workqueue: kacpi_notify acpi_os_execute_deferred
Call Trace:
<TASK>
dump_stack_lvl+0x5d/0x80
sysfs_warn_dup.cold+0x17/0x23
sysfs_create_dir_ns+0xce/0xe0
kobject_add_internal+0xba/0x250
kobject_add+0x96/0xc0
? get_device_parent+0xde/0x1e0
device_add+0xe2/0x870
__power_supply_register.part.0+0x20f/0x3f0
? wake_up_q+0x4e/0x90
sysfs_add_battery+0xa4/0x1d0 [battery]
acpi_battery_update+0x19e/0x290 [battery]
acpi_battery_notify+0x50/0x120 [battery]
acpi_ev_notify_dispatch+0x49/0x70
acpi_os_execute_deferred+0x1a/0x30
process_one_work+0x177/0x330
worker_thread+0x251/0x390
? __pfx_worker_thread+0x10/0x10
kthread+0xd2/0x100
? __pfx_kthread+0x10/0x10
ret_from_fork+0x34/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
kobject: kobject_add_internal failed for BAT1 with -EEXIST, don't try to register things with the same name in the same directory.
There are also other scenarios in which analogous issues may occur.
Address this by using a common lock in all of the code paths leading
to updates of driver interfaces: ACPI Notify () handler, system resume
callback and post-resume notification, device addition and removal.
This new lock replaces sysfs_lock that has been used only in
sysfs_remove_battery() which now is going to be always called under
the new lock, so it doesn't need any internal locking any more.
Fixes: 10666251554c ("ACPI: battery: Install Notify() handler directly")
Closes: https://lore.kernel.org/linux-acpi/20250910142653.313360-1-luogf2025@163.co…
Reported-by: GuangFei Luo <luogf2025(a)163.com>
Tested-by: GuangFei Luo <luogf2025(a)163.com>
Cc: 6.6+ <stable(a)vger.kernel.org> # 6.6+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com>
diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 6905b56bf3e4..67b76492c839 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -92,7 +92,7 @@ enum {
struct acpi_battery {
struct mutex lock;
- struct mutex sysfs_lock;
+ struct mutex update_lock;
struct power_supply *bat;
struct power_supply_desc bat_desc;
struct acpi_device *device;
@@ -904,15 +904,12 @@ static int sysfs_add_battery(struct acpi_battery *battery)
static void sysfs_remove_battery(struct acpi_battery *battery)
{
- mutex_lock(&battery->sysfs_lock);
- if (!battery->bat) {
- mutex_unlock(&battery->sysfs_lock);
+ if (!battery->bat)
return;
- }
+
battery_hook_remove_battery(battery);
power_supply_unregister(battery->bat);
battery->bat = NULL;
- mutex_unlock(&battery->sysfs_lock);
}
static void find_battery(const struct dmi_header *dm, void *private)
@@ -1072,6 +1069,9 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
if (!battery)
return;
+
+ guard(mutex)(&battery->update_lock);
+
old = battery->bat;
/*
* On Acer Aspire V5-573G notifications are sometimes triggered too
@@ -1094,21 +1094,22 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
}
static int battery_notify(struct notifier_block *nb,
- unsigned long mode, void *_unused)
+ unsigned long mode, void *_unused)
{
struct acpi_battery *battery = container_of(nb, struct acpi_battery,
pm_nb);
- int result;
- switch (mode) {
- case PM_POST_HIBERNATION:
- case PM_POST_SUSPEND:
+ if (mode == PM_POST_SUSPEND || mode == PM_POST_HIBERNATION) {
+ guard(mutex)(&battery->update_lock);
+
if (!acpi_battery_present(battery))
return 0;
if (battery->bat) {
acpi_battery_refresh(battery);
} else {
+ int result;
+
result = acpi_battery_get_info(battery);
if (result)
return result;
@@ -1120,7 +1121,6 @@ static int battery_notify(struct notifier_block *nb,
acpi_battery_init_alarm(battery);
acpi_battery_get_state(battery);
- break;
}
return 0;
@@ -1198,6 +1198,8 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
{
int retry, ret;
+ guard(mutex)(&battery->update_lock);
+
for (retry = 5; retry; retry--) {
ret = acpi_battery_update(battery, false);
if (!ret)
@@ -1208,6 +1210,13 @@ static int acpi_battery_update_retry(struct acpi_battery *battery)
return ret;
}
+static void sysfs_battery_cleanup(struct acpi_battery *battery)
+{
+ guard(mutex)(&battery->update_lock);
+
+ sysfs_remove_battery(battery);
+}
+
static int acpi_battery_add(struct acpi_device *device)
{
int result = 0;
@@ -1230,7 +1239,7 @@ static int acpi_battery_add(struct acpi_device *device)
if (result)
return result;
- result = devm_mutex_init(&device->dev, &battery->sysfs_lock);
+ result = devm_mutex_init(&device->dev, &battery->update_lock);
if (result)
return result;
@@ -1262,7 +1271,7 @@ static int acpi_battery_add(struct acpi_device *device)
device_init_wakeup(&device->dev, 0);
unregister_pm_notifier(&battery->pm_nb);
fail:
- sysfs_remove_battery(battery);
+ sysfs_battery_cleanup(battery);
return result;
}
@@ -1281,6 +1290,9 @@ static void acpi_battery_remove(struct acpi_device *device)
device_init_wakeup(&device->dev, 0);
unregister_pm_notifier(&battery->pm_nb);
+
+ guard(mutex)(&battery->update_lock);
+
sysfs_remove_battery(battery);
}
@@ -1297,6 +1309,9 @@ static int acpi_battery_resume(struct device *dev)
return -EINVAL;
battery->update_time = 0;
+
+ guard(mutex)(&battery->update_lock);
+
acpi_battery_update(battery, true);
return 0;
}