CVE-2026-97603

idpf: disable DIM work before freeing q_vectors

Published Sep 25, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

idpf: disable DIM work before freeing q_vectors

idpf never drains the Tx/Rx DIM works before freeing the memory they
live in. tx_dim and rx_dim are embedded in struct idpf_q_vector, they
are queued from the NAPI poll via net_dim(), and idpf_vport_intr_rel()
ends with kfree(rsrc->q_vectors). Nothing in the driver cancels them.

idpf_tx_dim_work() and idpf_rx_dim_work() then run on freed memory:
idpf_vport_intr_write_itr() writes the ITR register through
q_vector->intr_reg.tx_itr / rx_itr, void __iomem pointers loaded out of
the freed q_vector. No configuration is needed to get there --
IDPF_ITR_IS_DYNAMIC() is defined as (itr_mode) and idpf_vport_alloc()
initialises both modes to IDPF_ITR_DYNAMIC.

Draining after idpf_vport_intr_napi_dis_all() is not enough on its own.
idpf_net_dim() is called from inside the
"if (napi_complete_done(napi, work_done))" branch of the poll, and
napi_complete_done() has already cleared NAPIF_STATE_SCHED by then.
napi_disable_locked() waits only while (val & (NAPIF_STATE_SCHED |
NAPIF_STATE_NPSVC)), so napi_disable() can return while the poll tail is
still queueing the work, and a plain cancel_work_sync() would be
re-armed behind the drain.

Use disable_work_sync(): schedule_work() on a work with a non-zero
disable count is dropped by clear_pending_if_disabled() before
__queue_work() is reached.

Move idpf_init_dim() to idpf_vport_intr_alloc() so the works are
initialised on every path that can reach the drain -- the three
"goto intr_deinit" sites between idpf_vport_intr_init() and
idpf_vport_intr_ena() get there without the enable side having run.
Nothing re-enables them: rsrc->q_vectors is freed on every exit from
idpf_vport_open() and on every idpf_vport_stop(), so the count dies with
the object.

It is a race, not a deterministic failure -- net_dim() only schedules
once DIM_NEVENTS events have accumulated and the profile index changes.
A KASAN ifup/ifdown loop under load is the way to see it.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4850-1 linux-6.12 security update
Debian DSA Debian DSA DSA-6568-1 linux security update
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-362
CWE-416
Type Values Removed Values Added
Weaknesses CWE-825
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-362
CWE-416
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: idpf: disable DIM work before freeing q_vectors idpf never drains the Tx/Rx DIM works before freeing the memory they live in. tx_dim and rx_dim are embedded in struct idpf_q_vector, they are queued from the NAPI poll via net_dim(), and idpf_vport_intr_rel() ends with kfree(rsrc->q_vectors). Nothing in the driver cancels them. idpf_tx_dim_work() and idpf_rx_dim_work() then run on freed memory: idpf_vport_intr_write_itr() writes the ITR register through q_vector->intr_reg.tx_itr / rx_itr, void __iomem pointers loaded out of the freed q_vector. No configuration is needed to get there -- IDPF_ITR_IS_DYNAMIC() is defined as (itr_mode) and idpf_vport_alloc() initialises both modes to IDPF_ITR_DYNAMIC. Draining after idpf_vport_intr_napi_dis_all() is not enough on its own. idpf_net_dim() is called from inside the "if (napi_complete_done(napi, work_done))" branch of the poll, and napi_complete_done() has already cleared NAPIF_STATE_SCHED by then. napi_disable_locked() waits only while (val & (NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC)), so napi_disable() can return while the poll tail is still queueing the work, and a plain cancel_work_sync() would be re-armed behind the drain. Use disable_work_sync(): schedule_work() on a work with a non-zero disable count is dropped by clear_pending_if_disabled() before __queue_work() is reached. Move idpf_init_dim() to idpf_vport_intr_alloc() so the works are initialised on every path that can reach the drain -- the three "goto intr_deinit" sites between idpf_vport_intr_init() and idpf_vport_intr_ena() get there without the enable side having run. Nothing re-enables them: rsrc->q_vectors is freed on every exit from idpf_vport_open() and on every idpf_vport_stop(), so the count dies with the object. It is a race, not a deterministic failure -- net_dim() only schedules once DIM_NEVENTS events have accumulated and the profile index changes. A KASAN ifup/ifdown loop under load is the way to see it.
Title idpf: disable DIM work before freeing q_vectors
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 9:10 AM
Reserved
Sep 24, 2026, 4:01 PM
Status
Received
Published
Sep 25, 2026, 11:17 AM
Modified
Oct 19, 2026, 10:17 AM
Severity
Moderate
Public date
Sep 25, 2026, 12:00 AM