In the Linux kernel, the following vulnerability has been resolved:
driver core: fix potential deadlock in __driver_attach
In __driver_attach function, There are also AA deadlock problem,
like the commit b232b02bf3c2 ("driver core: fix deadlock in
__device_attach").
stack like commit b232b02bf3c2 ("driver core: fix deadlock in
__device_attach").
list below:
In __driver_attach function, The lock holding logic is as follows:
...
__driver_attach
if (driver_allows_async_probing(drv))
device_lock(dev) // get lock dev
async_schedule_dev(__driver_attach_async_helper, dev); // func
async_schedule_node
async_schedule_node_domain(func)
entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
/* when fail or work limit, sync to execute func, but
__driver_attach_async_helper will get lock dev as
will, which will lead to A-A deadlock. */
if (!entry || atomic_read(&entry_count) > MAX_WORK) {
func;
else
queue_work_node(node, system_unbound_wq, &entry->work)
device_unlock(dev)
As above show, when it is allowed to do async probes, because of
out of memory or work limit, async work is not be allowed, to do
sync execute instead. it will lead to A-A deadlock because of
__driver_attach_async_helper getting lock dev.
Reproduce:
and it can be reproduce by make the condition
(if (!entry || atomic_read(&entry_count) > MAX_WORK)) untenable, like
below:
[ 370.785650] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables
this message.
[ 370.787154] task:swapper/0 state:D stack: 0 pid: 1 ppid:
0 flags:0x00004000
[ 370.788865] Call Trace:
[ 370.789374]
[ 370.789841] __schedule+0x482/0x1050
[ 370.790613] schedule+0x92/0x1a0
[ 370.791290] schedule_preempt_disabled+0x2c/0x50
[ 370.792256] __mutex_lock.isra.0+0x757/0xec0
[ 370.793158] __mutex_lock_slowpath+0x1f/0x30
[ 370.794079] mutex_lock+0x50/0x60
[ 370.794795] __device_driver_lock+0x2f/0x70
[ 370.795677] ? driver_probe_device+0xd0/0xd0
[ 370.796576] __driver_attach_async_helper+0x1d/0xd0
[ 370.797318] ? driver_probe_device+0xd0/0xd0
[ 370.797957] async_schedule_node_domain+0xa5/0xc0
[ 370.798652] async_schedule_node+0x19/0x30
[ 370.799243] __driver_attach+0x246/0x290
[ 370.799828] ? driver_allows_async_probing+0xa0/0xa0
[ 370.800548] bus_for_each_dev+0x9d/0x130
[ 370.801132] driver_attach+0x22/0x30
[ 370.801666] bus_add_driver+0x290/0x340
[ 370.802246] driver_register+0x88/0x140
[ 370.802817] ? virtio_scsi_init+0x116/0x116
[ 370.803425] scsi_register_driver+0x1a/0x30
[ 370.804057] init_sd+0x184/0x226
[ 370.804533] do_one_initcall+0x71/0x3a0
[ 370.805107] kernel_init_freeable+0x39a/0x43a
[ 370.805759] ? rest_init+0x150/0x150
[ 370.806283] kernel_init+0x26/0x230
[ 370.806799] ret_from_fork+0x1f/0x30
To fix the deadlock, move the async_schedule_dev outside device_lock,
as we can see, in async_schedule_node_domain, the parameter of
queue_work_node is system_unbound_wq, so it can accept concurrent
operations. which will also not change the code logic, and will
not lead to deadlock.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-25). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it