In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix assertion of exclop condition when starting balance
Balance as exclusive state is compatible with paused balance and device
add, which makes some things more complicated. The assertion of valid
states when starting from paused balance needs to take into account two
more states, the combinations can be hit when there are several threads
racing to start balance and device add. This won't typically happen when
the commands are started from command line.
Scenario 1: With exclusive_operation state == BTRFS_EXCLOP_NONE.
Concurrently adding multiple devices to the same mount point and
btrfs_exclop_finish executed finishes before assertion in
btrfs_exclop_balance, exclusive_operation will changed to
BTRFS_EXCLOP_NONE state which lead to assertion failed:
fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD,
in fs/btrfs/ioctl.c:456
Call Trace:
<TASK>
btrfs_exclop_balance+0x13c/0x310
? memdup_user+0xab/0xc0
? PTR_ERR+0x17/0x20
btrfs_ioctl_add_dev+0x2ee/0x320
btrfs_ioctl+0x9d5/0x10d0
? btrfs_ioctl_encoded_write+0xb80/0xb80
__x64_sys_ioctl+0x197/0x210
do_syscall_64+0x3c/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Scenario 2: With exclusive_operation state == BTRFS_EXCLOP_BALANCE_PAUSED.
Concurrently adding multiple devices to the same mount point and
btrfs_exclop_balance executed finish before the latter thread execute
assertion in btrfs_exclop_balance, exclusive_operation will changed to
BTRFS_EXCLOP_BALANCE_PAUSED state which lead to assertion failed:
fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD ||
fs_info->exclusive_operation == BTRFS_EXCLOP_NONE,
fs/btrfs/ioctl.c:458
Call Trace:
<TASK>
btrfs_exclop_balance+0x240/0x410
? memdup_user+0xab/0xc0
? PTR_ERR+0x17/0x20
btrfs_ioctl_add_dev+0x2ee/0x320
btrfs_ioctl+0x9d5/0x10d0
? btrfs_ioctl_encoded_write+0xb80/0xb80
__x64_sys_ioctl+0x197/0x210
do_syscall_64+0x3c/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
An example of the failed assertion is below, which shows that the
paused balance is also needed to be checked.
root@syzkaller:/home/xsk# ./repro
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
[ 416.611428][ T7970] BTRFS info (device loop0): fs_info exclusive_operation: 0
Failed to add device /dev/vda, errno 14
[ 416.613973][ T7971] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.615456][ T7972] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.617528][ T7973] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.618359][ T7974] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.622589][ T7975] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.624034][ T7976] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.626420][ T7977] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.627643][ T7978] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.629006][ T7979] BTRFS info (device loop0): fs_info exclusive_operation: 3
[ 416.630298][ T7980] BTRFS info (device loop0): fs_info exclusive_operation: 3
Fai
---truncated---
btrfs: fix assertion of exclop condition when starting balance
Balance as exclusive state is compatible with paused balance and device
add, which makes some things more complicated. The assertion of valid
states when starting from paused balance needs to take into account two
more states, the combinations can be hit when there are several threads
racing to start balance and device add. This won't typically happen when
the commands are started from command line.
Scenario 1: With exclusive_operation state == BTRFS_EXCLOP_NONE.
Concurrently adding multiple devices to the same mount point and
btrfs_exclop_finish executed finishes before assertion in
btrfs_exclop_balance, exclusive_operation will changed to
BTRFS_EXCLOP_NONE state which lead to assertion failed:
fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD,
in fs/btrfs/ioctl.c:456
Call Trace:
<TASK>
btrfs_exclop_balance+0x13c/0x310
? memdup_user+0xab/0xc0
? PTR_ERR+0x17/0x20
btrfs_ioctl_add_dev+0x2ee/0x320
btrfs_ioctl+0x9d5/0x10d0
? btrfs_ioctl_encoded_write+0xb80/0xb80
__x64_sys_ioctl+0x197/0x210
do_syscall_64+0x3c/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Scenario 2: With exclusive_operation state == BTRFS_EXCLOP_BALANCE_PAUSED.
Concurrently adding multiple devices to the same mount point and
btrfs_exclop_balance executed finish before the latter thread execute
assertion in btrfs_exclop_balance, exclusive_operation will changed to
BTRFS_EXCLOP_BALANCE_PAUSED state which lead to assertion failed:
fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE ||
fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD ||
fs_info->exclusive_operation == BTRFS_EXCLOP_NONE,
fs/btrfs/ioctl.c:458
Call Trace:
<TASK>
btrfs_exclop_balance+0x240/0x410
? memdup_user+0xab/0xc0
? PTR_ERR+0x17/0x20
btrfs_ioctl_add_dev+0x2ee/0x320
btrfs_ioctl+0x9d5/0x10d0
? btrfs_ioctl_encoded_write+0xb80/0xb80
__x64_sys_ioctl+0x197/0x210
do_syscall_64+0x3c/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
An example of the failed assertion is below, which shows that the
paused balance is also needed to be checked.
root@syzkaller:/home/xsk# ./repro
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
Failed to add device /dev/vda, errno 14
[ 416.611428][ T7970] BTRFS info (device loop0): fs_info exclusive_operation: 0
Failed to add device /dev/vda, errno 14
[ 416.613973][ T7971] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.615456][ T7972] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.617528][ T7973] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.618359][ T7974] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.622589][ T7975] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.624034][ T7976] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.626420][ T7977] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.627643][ T7978] BTRFS info (device loop0): fs_info exclusive_operation: 3
Failed to add device /dev/vda, errno 14
[ 416.629006][ T7979] BTRFS info (device loop0): fs_info exclusive_operation: 3
[ 416.630298][ T7980] BTRFS info (device loop0): fs_info exclusive_operation: 3
Fai
---truncated---
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 24 Dec 2025 11:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: btrfs: fix assertion of exclop condition when starting balance Balance as exclusive state is compatible with paused balance and device add, which makes some things more complicated. The assertion of valid states when starting from paused balance needs to take into account two more states, the combinations can be hit when there are several threads racing to start balance and device add. This won't typically happen when the commands are started from command line. Scenario 1: With exclusive_operation state == BTRFS_EXCLOP_NONE. Concurrently adding multiple devices to the same mount point and btrfs_exclop_finish executed finishes before assertion in btrfs_exclop_balance, exclusive_operation will changed to BTRFS_EXCLOP_NONE state which lead to assertion failed: fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE || fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD, in fs/btrfs/ioctl.c:456 Call Trace: <TASK> btrfs_exclop_balance+0x13c/0x310 ? memdup_user+0xab/0xc0 ? PTR_ERR+0x17/0x20 btrfs_ioctl_add_dev+0x2ee/0x320 btrfs_ioctl+0x9d5/0x10d0 ? btrfs_ioctl_encoded_write+0xb80/0xb80 __x64_sys_ioctl+0x197/0x210 do_syscall_64+0x3c/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Scenario 2: With exclusive_operation state == BTRFS_EXCLOP_BALANCE_PAUSED. Concurrently adding multiple devices to the same mount point and btrfs_exclop_balance executed finish before the latter thread execute assertion in btrfs_exclop_balance, exclusive_operation will changed to BTRFS_EXCLOP_BALANCE_PAUSED state which lead to assertion failed: fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE || fs_info->exclusive_operation == BTRFS_EXCLOP_DEV_ADD || fs_info->exclusive_operation == BTRFS_EXCLOP_NONE, fs/btrfs/ioctl.c:458 Call Trace: <TASK> btrfs_exclop_balance+0x240/0x410 ? memdup_user+0xab/0xc0 ? PTR_ERR+0x17/0x20 btrfs_ioctl_add_dev+0x2ee/0x320 btrfs_ioctl+0x9d5/0x10d0 ? btrfs_ioctl_encoded_write+0xb80/0xb80 __x64_sys_ioctl+0x197/0x210 do_syscall_64+0x3c/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd An example of the failed assertion is below, which shows that the paused balance is also needed to be checked. root@syzkaller:/home/xsk# ./repro Failed to add device /dev/vda, errno 14 Failed to add device /dev/vda, errno 14 Failed to add device /dev/vda, errno 14 Failed to add device /dev/vda, errno 14 Failed to add device /dev/vda, errno 14 Failed to add device /dev/vda, errno 14 Failed to add device /dev/vda, errno 14 Failed to add device /dev/vda, errno 14 Failed to add device /dev/vda, errno 14 [ 416.611428][ T7970] BTRFS info (device loop0): fs_info exclusive_operation: 0 Failed to add device /dev/vda, errno 14 [ 416.613973][ T7971] BTRFS info (device loop0): fs_info exclusive_operation: 3 Failed to add device /dev/vda, errno 14 [ 416.615456][ T7972] BTRFS info (device loop0): fs_info exclusive_operation: 3 Failed to add device /dev/vda, errno 14 [ 416.617528][ T7973] BTRFS info (device loop0): fs_info exclusive_operation: 3 Failed to add device /dev/vda, errno 14 [ 416.618359][ T7974] BTRFS info (device loop0): fs_info exclusive_operation: 3 Failed to add device /dev/vda, errno 14 [ 416.622589][ T7975] BTRFS info (device loop0): fs_info exclusive_operation: 3 Failed to add device /dev/vda, errno 14 [ 416.624034][ T7976] BTRFS info (device loop0): fs_info exclusive_operation: 3 Failed to add device /dev/vda, errno 14 [ 416.626420][ T7977] BTRFS info (device loop0): fs_info exclusive_operation: 3 Failed to add device /dev/vda, errno 14 [ 416.627643][ T7978] BTRFS info (device loop0): fs_info exclusive_operation: 3 Failed to add device /dev/vda, errno 14 [ 416.629006][ T7979] BTRFS info (device loop0): fs_info exclusive_operation: 3 [ 416.630298][ T7980] BTRFS info (device loop0): fs_info exclusive_operation: 3 Fai ---truncated--- | |
| Title | btrfs: fix assertion of exclop condition when starting balance | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-12-24T10:55:37.699Z
Reserved: 2025-12-24T10:53:46.177Z
Link: CVE-2023-54002
Vulnrichment
No data.
NVD
Status : Received
Published: 2025-12-24T11:15:53.117
Modified: 2025-12-24T11:15:53.117
Link: CVE-2023-54002
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.