FKIE_CVE-2026-80866
Vulnerability from fkie_nvd - Published: 2026-09-04 17:16 - Updated: 2026-10-15 11:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
tipc: avoid busy looping in tipc_exit_net()
Blamed commit introduced a busy-wait loop in tipc_exit_net()
to wait for pending UDP bearer cleanup works to complete:
while (atomic_read(&tn->wq_count))
cond_resched();
This loop can busy-wait for a long time if cond_resched() is a NOP. This
typically happens if the netns exit is executed by a high priority task,
or under kernels configured without preemption (CONFIG_PREEMPT_NONE). In
such cases, it wastes CPU cycles and can lead to soft lockups.
Fix this by replacing the busy loop with wait_var_event(), allowing the
thread to sleep properly until the work queue count reaches zero.
Accordingly, update cleanup_bearer() to use atomic_dec_and_test() and
wake_up_var() to wake up the waiter when the count drops to zero.
This uses the global wait queue hash table, avoiding the need to bloat
struct tipc_net with a wait_queue_head_t. The atomic_dec_and_test()
provides the necessary memory barrier to ensure the wakeup is not missed.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/tipc/core.c",
"net/tipc/udp_media.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "7672973957e3e20780afe5937a9fec70b72bc060",
"status": "affected",
"version": "04c26faa51d1e2fe71cf13c45791f5174c37f986",
"versionType": "git"
},
{
"lessThan": "522d1d950b9e3b68190a6de7534827c8dccedb73",
"status": "affected",
"version": "04c26faa51d1e2fe71cf13c45791f5174c37f986",
"versionType": "git"
},
{
"lessThan": "c1481c94e74c955e0448ddf46b8615a44d840c1e",
"status": "affected",
"version": "04c26faa51d1e2fe71cf13c45791f5174c37f986",
"versionType": "git"
},
{
"status": "affected",
"version": "d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa",
"versionType": "git"
},
{
"status": "affected",
"version": "5195ec5e365a2a9331bfeb585b613a6e94f98dba",
"versionType": "git"
},
{
"status": "affected",
"version": "b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d",
"versionType": "git"
},
{
"lessThan": "5.5",
"status": "affected",
"version": "5.4.124",
"versionType": "semver"
},
{
"lessThan": "5.11",
"status": "affected",
"version": "5.10.42",
"versionType": "semver"
},
{
"lessThan": "5.13",
"status": "affected",
"version": "5.12.9",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/tipc/core.c",
"net/tipc/udp_media.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.13"
},
{
"lessThan": "5.13",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: avoid busy looping in tipc_exit_net()\n\nBlamed commit introduced a busy-wait loop in tipc_exit_net()\nto wait for pending UDP bearer cleanup works to complete:\n\n while (atomic_read(\u0026tn-\u003ewq_count))\n cond_resched();\n\nThis loop can busy-wait for a long time if cond_resched() is a NOP. This\ntypically happens if the netns exit is executed by a high priority task,\nor under kernels configured without preemption (CONFIG_PREEMPT_NONE). In\nsuch cases, it wastes CPU cycles and can lead to soft lockups.\n\nFix this by replacing the busy loop with wait_var_event(), allowing the\nthread to sleep properly until the work queue count reaches zero.\n\nAccordingly, update cleanup_bearer() to use atomic_dec_and_test() and\nwake_up_var() to wake up the waiter when the count drops to zero.\n\nThis uses the global wait queue hash table, avoiding the need to bloat\nstruct tipc_net with a wait_queue_head_t. The atomic_dec_and_test()\nprovides the necessary memory barrier to ensure the wakeup is not missed."
}
],
"id": "CVE-2026-80866",
"lastModified": "2026-10-15T11:17:52.417",
"metrics": {},
"published": "2026-09-04T17:16:58.390",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/522d1d950b9e3b68190a6de7534827c8dccedb73"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7672973957e3e20780afe5937a9fec70b72bc060"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c1481c94e74c955e0448ddf46b8615a44d840c1e"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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