CVE-2025-22053 in Linux
Summary
by MITRE • 04/16/2025
In the Linux kernel, the following vulnerability has been resolved:
net: ibmveth: make veth_pool_store stop hanging
v2: - Created a single error handling unlock and exit in veth_pool_store - Greatly expanded commit message with previous explanatory-only text
Summary: Use rtnl_mutex to synchronize veth_pool_store with itself, ibmveth_close and ibmveth_open, preventing multiple calls in a row to napi_disable.
Background: Two (or more) threads could call veth_pool_store through writing to /sys/devices/vio/30000002/pool*/*. You can do this easily with a little shell script. This causes a hang.
I configured LOCKDEP, compiled ibmveth.c with DEBUG, and built a new kernel. I ran this test again and saw:
Setting pool0/active to 0 Setting pool1/active to 1 [ 73.911067][ T4365] ibmveth 30000002 eth0: close starting
Setting pool1/active to 1 Setting pool1/active to 0 [ 73.911367][ T4366] ibmveth 30000002 eth0: close starting
[ 73.916056][ T4365] ibmveth 30000002 eth0: close complete
[ 73.916064][ T4365] ibmveth 30000002 eth0: open starting
[ 110.808564][ T712] systemd-journald[712]: Sent WATCHDOG=1 notification.
[ 230.808495][ T712] systemd-journald[712]: Sent WATCHDOG=1 notification.
[ 243.683786][ T123] INFO: task stress.sh:4365 blocked for more than 122 seconds.
[ 243.683827][ T123] Not tainted 6.14.0-01103-g2df0c02dab82-dirty #8
[ 243.683833][ T123] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 243.683838][ T123] task:stress.sh state:D stack:28096 pid:4365 tgid:4365 ppid:4364 task_flags:0x400040 flags:0x00042000
[ 243.683852][ T123] Call Trace:
[ 243.683857][ T123] [c00000000c38f690] [0000000000000001] 0x1 (unreliable)
[ 243.683868][ T123] [c00000000c38f840] [c00000000001f908] __switch_to+0x318/0x4e0
[ 243.683878][ T123] [c00000000c38f8a0] [c000000001549a70] __schedule+0x500/0x12a0
[ 243.683888][ T123] [c00000000c38f9a0] [c00000000154a878] schedule+0x68/0x210
[ 243.683896][ T123] [c00000000c38f9d0] [c00000000154ac80] schedule_preempt_disabled+0x30/0x50
[ 243.683904][ T123] [c00000000c38fa00] [c00000000154dbb0] __mutex_lock+0x730/0x10f0
[ 243.683913][ T123] [c00000000c38fb10] [c000000001154d40] napi_enable+0x30/0x60
[ 243.683921][ T123] [c00000000c38fb40] [c000000000f4ae94] ibmveth_open+0x68/0x5dc
[ 243.683928][ T123] [c00000000c38fbe0] [c000000000f4aa20] veth_pool_store+0x220/0x270
[ 243.683936][ T123] [c00000000c38fc70] [c000000000826278] sysfs_kf_write+0x68/0xb0
[ 243.683944][ T123] [c00000000c38fcb0] [c0000000008240b8] kernfs_fop_write_iter+0x198/0x2d0
[ 243.683951][ T123] [c00000000c38fd00] [c00000000071b9ac] vfs_write+0x34c/0x650
[ 243.683958][ T123] [c00000000c38fdc0] [c00000000071bea8] ksys_write+0x88/0x150
[ 243.683966][ T123] [c00000000c38fe10] [c0000000000317f4] system_call_exception+0x124/0x340
[ 243.683973][ T123] [c00000000c38fe50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
... [ 243.684087][ T123] Showing all locks held in the system:
[ 243.684095][ T123] 1 lock held by khungtaskd/123:
[ 243.684099][ T123] #0: c00000000278e370 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x50/0x248
[ 243.684114][ T123] 4 locks held by stress.sh/4365:
[ 243.684119][ T123] #0: c00000003a4cd3f8 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x88/0x150
[ 243.684132][ T123] #1: c000000041aea888 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x154/0x2d0
[ 243.684143][ T123] #2: c0000000366fb9a8 (kn->active#64){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x160/0x2d0
[ 243.684155][ T123] #3: c000000035ff4cb8 (&dev->lock){+.+.}-{3:3}, at: napi_enable+0x30/0x60
[ 243.684166][ T123] 5 locks held by stress.sh/4366:
[ 243.684170][ T123] #0: c00000003a4cd3f8 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x88/0x150
[ 243.
---truncated---
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Analysis
by VulDB Data Team • 02/15/2026
The vulnerability CVE-2025-22053 resides within the Linux kernel's ibmveth driver, which manages IBM PowerVM virtual Ethernet adapters. This issue manifests as a potential deadlock condition occurring during concurrent access to the virtual Ethernet pool configuration via sysfs interfaces. The root cause lies in insufficient synchronization mechanisms when multiple threads attempt to modify the pool state simultaneously through writes to /sys/devices/vio/30000002/pool/ paths. The flaw enables a race condition where threads can become indefinitely blocked, resulting in system hang conditions that severely impact availability and operational stability.
The technical implementation of this vulnerability stems from the absence of proper mutual exclusion when handling the veth_pool_store function, which processes writes to the pool configuration files. Without adequate synchronization, concurrent execution paths can lead to interleaved operations that cause the kernel to enter a deadlock state. The debugging output reveals a clear call trace showing that a thread blocked attempting to acquire a mutex while trying to re-enable NAPI (Network API) after a close operation, indicating that the synchronization mechanism failed to prevent concurrent access to critical sections. The system logs demonstrate that multiple threads attempting to modify the pool state through different sysfs interfaces cause the kernel to hang, with one thread waiting indefinitely for a lock held by another thread in a conflicting sequence.
The operational impact of this vulnerability extends beyond simple system unresponsiveness to potentially severe service disruption in virtualized environments. When systems employing IBM PowerVM virtualization experience this deadlock, network operations become completely blocked, affecting all network-dependent services and applications. The vulnerability particularly affects systems using the ibmveth driver in high-concurrency scenarios where multiple processes or threads attempt to configure virtual Ethernet pools simultaneously. The hang condition can persist for extended periods, as evidenced by the 122-second timeout before the kernel's hung task detection mechanism intervenes, potentially causing cascading failures in dependent services and applications.
The mitigation strategy for CVE-2025-22053 involves implementing proper locking mechanisms to synchronize access to the veth_pool_store function with other related operations such as ibmveth_close and ibmveth_open. The fix employs the rtnl_mutex, a well-established kernel synchronization primitive used for network device configuration operations, to ensure that only one thread can execute critical sections at any given time. This approach aligns with the Common Weakness Enumeration (CWE) category CWE-362, which addresses concurrent execution issues and race conditions in multi-threaded environments. Additionally, this solution corresponds to ATT&CK technique T1499.004, which deals with network denial of service through resource exhaustion or locking mechanisms, as the vulnerability can be exploited to cause system unresponsiveness through improper resource handling. The implementation of proper mutex locking prevents the interleaved execution that leads to the deadlock condition, ensuring that the network interface can be safely configured without risking system hang or service disruption.