A new warning in Clang 22 [1] complains that @clidr passed to
get_clidr_el1() is an uninitialized const pointer. get_clidr_el1()
doesn't really care since it casts away the const-ness anyways -- it is
a false positive.
| ../arch/arm64/kvm/sys_regs.c:2838:23: warning: variable 'clidr' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer]
| 2838 | get_clidr_el1(NULL, &clidr); /* Ugly... */
| | ^~~~~
This patch isn't needed for anything past 6.1 as this code section was
reworked in Commit 7af0c2534f4c ("KVM: arm64: Normalize cache
configuration"). Since there is no upstream equivalent, this patch just
needs to be applied to 5.15.
Disable this warning for sys_regs.o with an iron fist as it doesn't make
sense to waste maintainer's time or potentially break builds by
backporting large changelists from 6.2+.
Cc: stable(a)vger.kernel.org
Fixes: 7c8c5e6a9101e ("arm64: KVM: system register handling")
Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d44… [1]
Reviewed-by: Nathan Chancellor <nathan(a)kernel.org>
Signed-off-by: Justin Stitt <justinstitt(a)google.com>
---
Resending this with Nathan's RB tag, an updated commit log and better
recipients from checkpatch.pl.
I'm also sending a similar patch resend for 6.1.
---
arch/arm64/kvm/Makefile | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 989bb5dad2c8..109cca425d3e 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -25,3 +25,6 @@ kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \
vgic/vgic-its.o vgic/vgic-debug.o
kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o
+
+# Work around a false positive Clang 22 -Wuninitialized-const-pointer warning
+CFLAGS_sys_regs.o := $(call cc-disable-warning, uninitialized-const-pointer)
---
base-commit: 8bb7eca972ad531c9b149c0a51ab43a417385813
change-id: 20250728-b4-stable-disable-uninit-ptr-warn-5-15-c0c9db3df206
Best regards,
--
Justin Stitt <justinstitt(a)google.com>
A new warning in Clang 22 [1] complains that @clidr passed to
get_clidr_el1() is an uninitialized const pointer. get_clidr_el1()
doesn't really care since it casts away the const-ness anyways -- it is
a false positive.
This patch isn't needed for anything past 6.1 as this code section was
reworked in Commit 7af0c2534f4c ("KVM: arm64: Normalize cache
configuration") which incidentally removed the aforementioned warning.
Since there is no upstream equivalent, this patch just needs to be
applied to 6.1.
Disable this warning for sys_regs.o instead of backporting the patches
from 6.2+ that modified this code area.
Cc: stable(a)vger.kernel.org
Fixes: 7c8c5e6a9101e ("arm64: KVM: system register handling")
Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d44… [1]
Reviewed-by: Nathan Chancellor <nathan(a)kernel.org>
Signed-off-by: Justin Stitt <justinstitt(a)google.com>
---
Changes in v2:
- disable warning for TU instead of initialising the struct
- update commit message
- Link to v1: https://lore.kernel.org/all/20250724-b4-clidr-unint-const-ptr-v1-1-67c4d620…
- Link to v1 resend (sent wrong diff, thanks Nathan): https://lore.kernel.org/all/20251204-b4-clidr-unint-const-ptr-v1-1-95161315…
---
arch/arm64/kvm/Makefile | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 5e33c2d4645a..5fdb5331bfad 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -24,6 +24,9 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o pmu.o
+# Work around a false positive Clang 22 -Wuninitialized-const-pointer warning
+CFLAGS_sys_regs.o := $(call cc-disable-warning, uninitialized-const-pointer)
+
always-y := hyp_constants.h hyp-constants.s
define rule_gen_hyp_constants
---
base-commit: 830b3c68c1fb1e9176028d02ef86f3cf76aa2476
change-id: 20250728-stable-disable-unit-ptr-warn-281fee82539c
Best regards,
--
Justin Stitt <justinstitt(a)google.com>
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 dae9750105cf93ac1e156ef91f4beeb53bd64777
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122958-statue-subtotal-2f1c@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From dae9750105cf93ac1e156ef91f4beeb53bd64777 Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111(a)xry111.site>
Date: Fri, 28 Nov 2025 15:50:32 +0800
Subject: [PATCH] gpio: loongson: Switch 2K2000/3000 GPIO to BYTE_CTRL_MODE
The manuals of 2K2000 says both BIT_CTRL_MODE and BYTE_CTRL_MODE are
supported but the latter is recommended. Also on 2K3000, per the ACPI
DSDT the GPIO controller is compatible with 2K2000, but it fails to
operate GPIOs 62 and 63 (and maybe others) using BIT_CTRL_MODE.
Using BYTE_CTRL_MODE also makes those 2K3000 GPIOs work.
Fixes: 3feb70a61740 ("gpio: loongson: add more gpio chip support")
Cc: stable(a)vger.kernel.org
Signed-off-by: Xi Ruoyao <xry111(a)xry111.site>
Reviewed-by: Huacai Chen <chenhuacai(a)loongson.cn>
Link: https://lore.kernel.org/r/20251128075033.255821-1-xry111@xry111.site
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski(a)linaro.org>
diff --git a/drivers/gpio/gpio-loongson-64bit.c b/drivers/gpio/gpio-loongson-64bit.c
index d4e291b275f0..77d07e31366f 100644
--- a/drivers/gpio/gpio-loongson-64bit.c
+++ b/drivers/gpio/gpio-loongson-64bit.c
@@ -408,11 +408,11 @@ static const struct loongson_gpio_chip_data loongson_gpio_ls2k2000_data0 = {
static const struct loongson_gpio_chip_data loongson_gpio_ls2k2000_data1 = {
.label = "ls2k2000_gpio",
- .mode = BIT_CTRL_MODE,
- .conf_offset = 0x0,
- .in_offset = 0x20,
- .out_offset = 0x10,
- .inten_offset = 0x30,
+ .mode = BYTE_CTRL_MODE,
+ .conf_offset = 0x800,
+ .in_offset = 0xa00,
+ .out_offset = 0x900,
+ .inten_offset = 0xb00,
};
static const struct loongson_gpio_chip_data loongson_gpio_ls2k2000_data2 = {
The patch below does not apply to the 5.10-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-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x ee5a977b4e771cc181f39d504426dbd31ed701cc
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122959-unawake-devious-8898@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ee5a977b4e771cc181f39d504426dbd31ed701cc Mon Sep 17 00:00:00 2001
From: Fedor Pchelkin <pchelkin(a)ispras.ru>
Date: Sat, 1 Nov 2025 19:04:28 +0300
Subject: [PATCH] ext4: fix string copying in parse_apply_sb_mount_options()
strscpy_pad() can't be used to copy a non-NUL-term string into a NUL-term
string of possibly bigger size. Commit 0efc5990bca5 ("string.h: Introduce
memtostr() and memtostr_pad()") provides additional information in that
regard. So if this happens, the following warning is observed:
strnlen: detected buffer overflow: 65 byte read of buffer size 64
WARNING: CPU: 0 PID: 28655 at lib/string_helpers.c:1032 __fortify_report+0x96/0xc0 lib/string_helpers.c:1032
Modules linked in:
CPU: 0 UID: 0 PID: 28655 Comm: syz-executor.3 Not tainted 6.12.54-syzkaller-00144-g5f0270f1ba00 #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__fortify_report+0x96/0xc0 lib/string_helpers.c:1032
Call Trace:
<TASK>
__fortify_panic+0x1f/0x30 lib/string_helpers.c:1039
strnlen include/linux/fortify-string.h:235 [inline]
sized_strscpy include/linux/fortify-string.h:309 [inline]
parse_apply_sb_mount_options fs/ext4/super.c:2504 [inline]
__ext4_fill_super fs/ext4/super.c:5261 [inline]
ext4_fill_super+0x3c35/0xad00 fs/ext4/super.c:5706
get_tree_bdev_flags+0x387/0x620 fs/super.c:1636
vfs_get_tree+0x93/0x380 fs/super.c:1814
do_new_mount fs/namespace.c:3553 [inline]
path_mount+0x6ae/0x1f70 fs/namespace.c:3880
do_mount fs/namespace.c:3893 [inline]
__do_sys_mount fs/namespace.c:4103 [inline]
__se_sys_mount fs/namespace.c:4080 [inline]
__x64_sys_mount+0x280/0x300 fs/namespace.c:4080
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x64/0x140 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Since userspace is expected to provide s_mount_opts field to be at most 63
characters long with the ending byte being NUL-term, use a 64-byte buffer
which matches the size of s_mount_opts, so that strscpy_pad() does its job
properly. Return with error if the user still managed to provide a
non-NUL-term string here.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 8ecb790ea8c3 ("ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()")
Cc: stable(a)vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin(a)ispras.ru>
Reviewed-by: Baokun Li <libaokun1(a)huawei.com>
Reviewed-by: Jan Kara <jack(a)suse.cz>
Message-ID: <20251101160430.222297-1-pchelkin(a)ispras.ru>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7de15249e826..d1ba894c0e0a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2476,7 +2476,7 @@ 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[65];
+ char s_mount_opts[64];
struct ext4_fs_context *s_ctx = NULL;
struct fs_context *fc = NULL;
int ret = -ENOMEM;
@@ -2484,7 +2484,8 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
if (!sbi->s_es->s_mount_opts[0])
return 0;
- strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts);
+ if (strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts) < 0)
+ return -E2BIG;
fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL);
if (!fc)
The patch below does not apply to the 5.10-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-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 6abfe107894af7e8ce3a2e120c619d81ee764ad5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122936-jaunt-sliding-0a13@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 6abfe107894af7e8ce3a2e120c619d81ee764ad5 Mon Sep 17 00:00:00 2001
From: Ye Bin <yebin10(a)huawei.com>
Date: Mon, 3 Nov 2025 09:01:23 +0800
Subject: [PATCH] jbd2: fix the inconsistency between checksum and data in
memory for journal sb
Copying the file system while it is mounted as read-only results in
a mount failure:
[~]# mkfs.ext4 -F /dev/sdc
[~]# mount /dev/sdc -o ro /mnt/test
[~]# dd if=/dev/sdc of=/dev/sda bs=1M
[~]# mount /dev/sda /mnt/test1
[ 1094.849826] JBD2: journal checksum error
[ 1094.850927] EXT4-fs (sda): Could not load journal inode
mount: mount /dev/sda on /mnt/test1 failed: Bad message
The process described above is just an abstracted way I came up with to
reproduce the issue. In the actual scenario, the file system was mounted
read-only and then copied while it was still mounted. It was found that
the mount operation failed. The user intended to verify the data or use
it as a backup, and this action was performed during a version upgrade.
Above issue may happen as follows:
ext4_fill_super
set_journal_csum_feature_set(sb)
if (ext4_has_metadata_csum(sb))
incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
if (test_opt(sb, JOURNAL_CHECKSUM)
jbd2_journal_set_features(sbi->s_journal, compat, 0, incompat);
lock_buffer(journal->j_sb_buffer);
sb->s_feature_incompat |= cpu_to_be32(incompat);
//The data in the journal sb was modified, but the checksum was not
updated, so the data remaining in memory has a mismatch between the
data and the checksum.
unlock_buffer(journal->j_sb_buffer);
In this case, the journal sb copied over is in a state where the checksum
and data are inconsistent, so mounting fails.
To solve the above issue, update the checksum in memory after modifying
the journal sb.
Fixes: 4fd5ea43bc11 ("jbd2: checksum journal superblock")
Signed-off-by: Ye Bin <yebin10(a)huawei.com>
Reviewed-by: Baokun Li <libaokun1(a)huawei.com>
Reviewed-by: Darrick J. Wong <djwong(a)kernel.org>
Reviewed-by: Jan Kara <jack(a)suse.cz>
Message-ID: <20251103010123.3753631-1-yebin(a)huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
Cc: stable(a)kernel.org
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 2fe1786a8f1b..c973162d5b31 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2354,6 +2354,12 @@ int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
sb->s_feature_compat |= cpu_to_be32(compat);
sb->s_feature_ro_compat |= cpu_to_be32(ro);
sb->s_feature_incompat |= cpu_to_be32(incompat);
+ /*
+ * Update the checksum now so that it is valid even for read-only
+ * filesystems where jbd2_write_superblock() doesn't get called.
+ */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ sb->s_checksum = jbd2_superblock_csum(sb);
unlock_buffer(journal->j_sb_buffer);
jbd2_journal_init_transaction_limits(journal);
@@ -2383,9 +2389,17 @@ void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
sb = journal->j_superblock;
+ lock_buffer(journal->j_sb_buffer);
sb->s_feature_compat &= ~cpu_to_be32(compat);
sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
sb->s_feature_incompat &= ~cpu_to_be32(incompat);
+ /*
+ * Update the checksum now so that it is valid even for read-only
+ * filesystems where jbd2_write_superblock() doesn't get called.
+ */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ sb->s_checksum = jbd2_superblock_csum(sb);
+ unlock_buffer(journal->j_sb_buffer);
jbd2_journal_init_transaction_limits(journal);
}
EXPORT_SYMBOL(jbd2_journal_clear_features);
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 6abfe107894af7e8ce3a2e120c619d81ee764ad5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122935-turban-sweep-c818@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 6abfe107894af7e8ce3a2e120c619d81ee764ad5 Mon Sep 17 00:00:00 2001
From: Ye Bin <yebin10(a)huawei.com>
Date: Mon, 3 Nov 2025 09:01:23 +0800
Subject: [PATCH] jbd2: fix the inconsistency between checksum and data in
memory for journal sb
Copying the file system while it is mounted as read-only results in
a mount failure:
[~]# mkfs.ext4 -F /dev/sdc
[~]# mount /dev/sdc -o ro /mnt/test
[~]# dd if=/dev/sdc of=/dev/sda bs=1M
[~]# mount /dev/sda /mnt/test1
[ 1094.849826] JBD2: journal checksum error
[ 1094.850927] EXT4-fs (sda): Could not load journal inode
mount: mount /dev/sda on /mnt/test1 failed: Bad message
The process described above is just an abstracted way I came up with to
reproduce the issue. In the actual scenario, the file system was mounted
read-only and then copied while it was still mounted. It was found that
the mount operation failed. The user intended to verify the data or use
it as a backup, and this action was performed during a version upgrade.
Above issue may happen as follows:
ext4_fill_super
set_journal_csum_feature_set(sb)
if (ext4_has_metadata_csum(sb))
incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
if (test_opt(sb, JOURNAL_CHECKSUM)
jbd2_journal_set_features(sbi->s_journal, compat, 0, incompat);
lock_buffer(journal->j_sb_buffer);
sb->s_feature_incompat |= cpu_to_be32(incompat);
//The data in the journal sb was modified, but the checksum was not
updated, so the data remaining in memory has a mismatch between the
data and the checksum.
unlock_buffer(journal->j_sb_buffer);
In this case, the journal sb copied over is in a state where the checksum
and data are inconsistent, so mounting fails.
To solve the above issue, update the checksum in memory after modifying
the journal sb.
Fixes: 4fd5ea43bc11 ("jbd2: checksum journal superblock")
Signed-off-by: Ye Bin <yebin10(a)huawei.com>
Reviewed-by: Baokun Li <libaokun1(a)huawei.com>
Reviewed-by: Darrick J. Wong <djwong(a)kernel.org>
Reviewed-by: Jan Kara <jack(a)suse.cz>
Message-ID: <20251103010123.3753631-1-yebin(a)huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
Cc: stable(a)kernel.org
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 2fe1786a8f1b..c973162d5b31 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2354,6 +2354,12 @@ int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
sb->s_feature_compat |= cpu_to_be32(compat);
sb->s_feature_ro_compat |= cpu_to_be32(ro);
sb->s_feature_incompat |= cpu_to_be32(incompat);
+ /*
+ * Update the checksum now so that it is valid even for read-only
+ * filesystems where jbd2_write_superblock() doesn't get called.
+ */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ sb->s_checksum = jbd2_superblock_csum(sb);
unlock_buffer(journal->j_sb_buffer);
jbd2_journal_init_transaction_limits(journal);
@@ -2383,9 +2389,17 @@ void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
sb = journal->j_superblock;
+ lock_buffer(journal->j_sb_buffer);
sb->s_feature_compat &= ~cpu_to_be32(compat);
sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
sb->s_feature_incompat &= ~cpu_to_be32(incompat);
+ /*
+ * Update the checksum now so that it is valid even for read-only
+ * filesystems where jbd2_write_superblock() doesn't get called.
+ */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ sb->s_checksum = jbd2_superblock_csum(sb);
+ unlock_buffer(journal->j_sb_buffer);
jbd2_journal_init_transaction_limits(journal);
}
EXPORT_SYMBOL(jbd2_journal_clear_features);
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 ee5a977b4e771cc181f39d504426dbd31ed701cc
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122957-crevice-busily-7e0e@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ee5a977b4e771cc181f39d504426dbd31ed701cc Mon Sep 17 00:00:00 2001
From: Fedor Pchelkin <pchelkin(a)ispras.ru>
Date: Sat, 1 Nov 2025 19:04:28 +0300
Subject: [PATCH] ext4: fix string copying in parse_apply_sb_mount_options()
strscpy_pad() can't be used to copy a non-NUL-term string into a NUL-term
string of possibly bigger size. Commit 0efc5990bca5 ("string.h: Introduce
memtostr() and memtostr_pad()") provides additional information in that
regard. So if this happens, the following warning is observed:
strnlen: detected buffer overflow: 65 byte read of buffer size 64
WARNING: CPU: 0 PID: 28655 at lib/string_helpers.c:1032 __fortify_report+0x96/0xc0 lib/string_helpers.c:1032
Modules linked in:
CPU: 0 UID: 0 PID: 28655 Comm: syz-executor.3 Not tainted 6.12.54-syzkaller-00144-g5f0270f1ba00 #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__fortify_report+0x96/0xc0 lib/string_helpers.c:1032
Call Trace:
<TASK>
__fortify_panic+0x1f/0x30 lib/string_helpers.c:1039
strnlen include/linux/fortify-string.h:235 [inline]
sized_strscpy include/linux/fortify-string.h:309 [inline]
parse_apply_sb_mount_options fs/ext4/super.c:2504 [inline]
__ext4_fill_super fs/ext4/super.c:5261 [inline]
ext4_fill_super+0x3c35/0xad00 fs/ext4/super.c:5706
get_tree_bdev_flags+0x387/0x620 fs/super.c:1636
vfs_get_tree+0x93/0x380 fs/super.c:1814
do_new_mount fs/namespace.c:3553 [inline]
path_mount+0x6ae/0x1f70 fs/namespace.c:3880
do_mount fs/namespace.c:3893 [inline]
__do_sys_mount fs/namespace.c:4103 [inline]
__se_sys_mount fs/namespace.c:4080 [inline]
__x64_sys_mount+0x280/0x300 fs/namespace.c:4080
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x64/0x140 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Since userspace is expected to provide s_mount_opts field to be at most 63
characters long with the ending byte being NUL-term, use a 64-byte buffer
which matches the size of s_mount_opts, so that strscpy_pad() does its job
properly. Return with error if the user still managed to provide a
non-NUL-term string here.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 8ecb790ea8c3 ("ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()")
Cc: stable(a)vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin(a)ispras.ru>
Reviewed-by: Baokun Li <libaokun1(a)huawei.com>
Reviewed-by: Jan Kara <jack(a)suse.cz>
Message-ID: <20251101160430.222297-1-pchelkin(a)ispras.ru>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7de15249e826..d1ba894c0e0a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2476,7 +2476,7 @@ 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[65];
+ char s_mount_opts[64];
struct ext4_fs_context *s_ctx = NULL;
struct fs_context *fc = NULL;
int ret = -ENOMEM;
@@ -2484,7 +2484,8 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
if (!sbi->s_es->s_mount_opts[0])
return 0;
- strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts);
+ if (strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts) < 0)
+ return -E2BIG;
fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL);
if (!fc)
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 ee5a977b4e771cc181f39d504426dbd31ed701cc
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122956-dropkick-outlast-5a49@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ee5a977b4e771cc181f39d504426dbd31ed701cc Mon Sep 17 00:00:00 2001
From: Fedor Pchelkin <pchelkin(a)ispras.ru>
Date: Sat, 1 Nov 2025 19:04:28 +0300
Subject: [PATCH] ext4: fix string copying in parse_apply_sb_mount_options()
strscpy_pad() can't be used to copy a non-NUL-term string into a NUL-term
string of possibly bigger size. Commit 0efc5990bca5 ("string.h: Introduce
memtostr() and memtostr_pad()") provides additional information in that
regard. So if this happens, the following warning is observed:
strnlen: detected buffer overflow: 65 byte read of buffer size 64
WARNING: CPU: 0 PID: 28655 at lib/string_helpers.c:1032 __fortify_report+0x96/0xc0 lib/string_helpers.c:1032
Modules linked in:
CPU: 0 UID: 0 PID: 28655 Comm: syz-executor.3 Not tainted 6.12.54-syzkaller-00144-g5f0270f1ba00 #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__fortify_report+0x96/0xc0 lib/string_helpers.c:1032
Call Trace:
<TASK>
__fortify_panic+0x1f/0x30 lib/string_helpers.c:1039
strnlen include/linux/fortify-string.h:235 [inline]
sized_strscpy include/linux/fortify-string.h:309 [inline]
parse_apply_sb_mount_options fs/ext4/super.c:2504 [inline]
__ext4_fill_super fs/ext4/super.c:5261 [inline]
ext4_fill_super+0x3c35/0xad00 fs/ext4/super.c:5706
get_tree_bdev_flags+0x387/0x620 fs/super.c:1636
vfs_get_tree+0x93/0x380 fs/super.c:1814
do_new_mount fs/namespace.c:3553 [inline]
path_mount+0x6ae/0x1f70 fs/namespace.c:3880
do_mount fs/namespace.c:3893 [inline]
__do_sys_mount fs/namespace.c:4103 [inline]
__se_sys_mount fs/namespace.c:4080 [inline]
__x64_sys_mount+0x280/0x300 fs/namespace.c:4080
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x64/0x140 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Since userspace is expected to provide s_mount_opts field to be at most 63
characters long with the ending byte being NUL-term, use a 64-byte buffer
which matches the size of s_mount_opts, so that strscpy_pad() does its job
properly. Return with error if the user still managed to provide a
non-NUL-term string here.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 8ecb790ea8c3 ("ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()")
Cc: stable(a)vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin(a)ispras.ru>
Reviewed-by: Baokun Li <libaokun1(a)huawei.com>
Reviewed-by: Jan Kara <jack(a)suse.cz>
Message-ID: <20251101160430.222297-1-pchelkin(a)ispras.ru>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7de15249e826..d1ba894c0e0a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2476,7 +2476,7 @@ 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[65];
+ char s_mount_opts[64];
struct ext4_fs_context *s_ctx = NULL;
struct fs_context *fc = NULL;
int ret = -ENOMEM;
@@ -2484,7 +2484,8 @@ static int parse_apply_sb_mount_options(struct super_block *sb,
if (!sbi->s_es->s_mount_opts[0])
return 0;
- strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts);
+ if (strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts) < 0)
+ return -E2BIG;
fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL);
if (!fc)
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 6abfe107894af7e8ce3a2e120c619d81ee764ad5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122934-exclude-sevenfold-d418@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 6abfe107894af7e8ce3a2e120c619d81ee764ad5 Mon Sep 17 00:00:00 2001
From: Ye Bin <yebin10(a)huawei.com>
Date: Mon, 3 Nov 2025 09:01:23 +0800
Subject: [PATCH] jbd2: fix the inconsistency between checksum and data in
memory for journal sb
Copying the file system while it is mounted as read-only results in
a mount failure:
[~]# mkfs.ext4 -F /dev/sdc
[~]# mount /dev/sdc -o ro /mnt/test
[~]# dd if=/dev/sdc of=/dev/sda bs=1M
[~]# mount /dev/sda /mnt/test1
[ 1094.849826] JBD2: journal checksum error
[ 1094.850927] EXT4-fs (sda): Could not load journal inode
mount: mount /dev/sda on /mnt/test1 failed: Bad message
The process described above is just an abstracted way I came up with to
reproduce the issue. In the actual scenario, the file system was mounted
read-only and then copied while it was still mounted. It was found that
the mount operation failed. The user intended to verify the data or use
it as a backup, and this action was performed during a version upgrade.
Above issue may happen as follows:
ext4_fill_super
set_journal_csum_feature_set(sb)
if (ext4_has_metadata_csum(sb))
incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
if (test_opt(sb, JOURNAL_CHECKSUM)
jbd2_journal_set_features(sbi->s_journal, compat, 0, incompat);
lock_buffer(journal->j_sb_buffer);
sb->s_feature_incompat |= cpu_to_be32(incompat);
//The data in the journal sb was modified, but the checksum was not
updated, so the data remaining in memory has a mismatch between the
data and the checksum.
unlock_buffer(journal->j_sb_buffer);
In this case, the journal sb copied over is in a state where the checksum
and data are inconsistent, so mounting fails.
To solve the above issue, update the checksum in memory after modifying
the journal sb.
Fixes: 4fd5ea43bc11 ("jbd2: checksum journal superblock")
Signed-off-by: Ye Bin <yebin10(a)huawei.com>
Reviewed-by: Baokun Li <libaokun1(a)huawei.com>
Reviewed-by: Darrick J. Wong <djwong(a)kernel.org>
Reviewed-by: Jan Kara <jack(a)suse.cz>
Message-ID: <20251103010123.3753631-1-yebin(a)huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
Cc: stable(a)kernel.org
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 2fe1786a8f1b..c973162d5b31 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2354,6 +2354,12 @@ int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
sb->s_feature_compat |= cpu_to_be32(compat);
sb->s_feature_ro_compat |= cpu_to_be32(ro);
sb->s_feature_incompat |= cpu_to_be32(incompat);
+ /*
+ * Update the checksum now so that it is valid even for read-only
+ * filesystems where jbd2_write_superblock() doesn't get called.
+ */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ sb->s_checksum = jbd2_superblock_csum(sb);
unlock_buffer(journal->j_sb_buffer);
jbd2_journal_init_transaction_limits(journal);
@@ -2383,9 +2389,17 @@ void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
sb = journal->j_superblock;
+ lock_buffer(journal->j_sb_buffer);
sb->s_feature_compat &= ~cpu_to_be32(compat);
sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
sb->s_feature_incompat &= ~cpu_to_be32(incompat);
+ /*
+ * Update the checksum now so that it is valid even for read-only
+ * filesystems where jbd2_write_superblock() doesn't get called.
+ */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ sb->s_checksum = jbd2_superblock_csum(sb);
+ unlock_buffer(journal->j_sb_buffer);
jbd2_journal_init_transaction_limits(journal);
}
EXPORT_SYMBOL(jbd2_journal_clear_features);