CVE-2026-90081
net/rds: use wq_has_sleeper() in rds_cong_map_updated()
Published Sep 17, 2026
CVSS n/a
EPSS < 1%
KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:
net/rds: use wq_has_sleeper() in rds_cong_map_updated()
rds_cong_map_updated() runs after a peer's congestion map has been
rewritten (by rds_tcp_cong_recv() and rds_ib_cong_recv(), or the
clear-all in the loopback and IB send-completion paths). It bumps
rds_cong_generation and then checks waitqueue_active() on
map->m_waitq and on rds_poll_waitq to decide whether anyone needs
waking. atomic_inc() carries no ordering and waitqueue_active() is a
plain load, so nothing orders the map and generation stores before
the wait queue reads. The waiters do the mirror image: rds_cong_wait()
adds itself to m_waitq and then tests the port bit, and rds_poll()
registers on rds_poll_waitq and then reads the generation. That is
the store-buffering pattern described above waitqueue_active() in
include/linux/wait.h - the updater can observe an empty wait queue
while the waiter still observes the port as congested, and no wake-up
is issued.
rds_cong_wait() is an interruptible sleep with no timeout, so a
sender blocked on a congested port stays blocked until the next
congestion update from that peer arrives or a signal is delivered.
A poll() waiter misses the map-updated notification the same way.
Use wq_has_sleeper(), which is waitqueue_active() preceded by the
required full barrier, as rds_tcp_state_change() already does for
the same pattern.
net/rds: use wq_has_sleeper() in rds_cong_map_updated()
rds_cong_map_updated() runs after a peer's congestion map has been
rewritten (by rds_tcp_cong_recv() and rds_ib_cong_recv(), or the
clear-all in the loopback and IB send-completion paths). It bumps
rds_cong_generation and then checks waitqueue_active() on
map->m_waitq and on rds_poll_waitq to decide whether anyone needs
waking. atomic_inc() carries no ordering and waitqueue_active() is a
plain load, so nothing orders the map and generation stores before
the wait queue reads. The waiters do the mirror image: rds_cong_wait()
adds itself to m_waitq and then tests the port bit, and rds_poll()
registers on rds_poll_waitq and then reads the generation. That is
the store-buffering pattern described above waitqueue_active() in
include/linux/wait.h - the updater can observe an empty wait queue
while the waiter still observes the port as congested, and no wake-up
is issued.
rds_cong_wait() is an interruptible sleep with no timeout, so a
sender blocked on a congested port stays blocked until the next
congestion update from that peer arrives or a signal is delivered.
A poll() waiter misses the map-updated notification the same way.
Use wq_has_sleeper(), which is waitqueue_active() preceded by the
required full barrier, as rds_tcp_state_change() already does for
the same pattern.
Affected Products
-
CVE record
-
NVD configurations
No data
-
Red Hat packages
No data
-
OpenCVE enrichment
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
| Vendor | Product | Versions | ||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux Kernel |
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| Linux | Linux Kernel |
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Remediation
Tracking
Advisories
| Source | ID | Title |
|---|---|---|
 Debian DLA |
DLA-4817-1 | linux-6.12 security update |
| Debian DLA |
DLA-4841-1 | linux security update |
 Debian DSA |
DSA-6528-1 | linux security update |
 Ubuntu USN |
USN-8961-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9019-1 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-9020-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9022-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9023-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9024-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9025-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-9026-1 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-9029-1 | Linux kernel (Raspberry Pi) vulnerabilities |
| Ubuntu USN |
USN-9039-1 | Linux kernel (Azure CVM) vulnerabilities |
| Ubuntu USN |
USN-9040-1 | Linux kernel (Low Latency NVIDIA) vulnerabilities |
| Ubuntu USN |
USN-9066-1 | Linux kernel (HWE) vulnerabilities |
| Ubuntu USN |
USN-9091-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Metrics
No CVSS v4.0
No CVSS v3.1
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.216% probability within 30 days)
Key SSVC decision points have not yet been added.
References
History
Sep 20, 2026 4:45 AM
Weaknesses updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-362 |
Sep 17, 2026 4:30 PM
Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net/rds: use wq_has_sleeper() in rds_cong_map_updated() rds_cong_map_updated() runs after a peer's congestion map has been rewritten (by rds_tcp_cong_recv() and rds_ib_cong_recv(), or the clear-all in the loopback and IB send-completion paths). It bumps rds_cong_generation and then checks waitqueue_active() on map->m_waitq and on rds_poll_waitq to decide whether anyone needs waking. atomic_inc() carries no ordering and waitqueue_active() is a plain load, so nothing orders the map and generation stores before the wait queue reads. The waiters do the mirror image: rds_cong_wait() adds itself to m_waitq and then tests the port bit, and rds_poll() registers on rds_poll_waitq and then reads the generation. That is the store-buffering pattern described above waitqueue_active() in include/linux/wait.h - the updater can observe an empty wait queue while the waiter still observes the port as congested, and no wake-up is issued. rds_cong_wait() is an interruptible sleep with no timeout, so a sender blocked on a congested port stays blocked until the next congestion update from that peer arrives or a signal is delivered. A poll() waiter misses the map-updated notification the same way. Use wq_has_sleeper(), which is waitqueue_active() preceded by the required full barrier, as rds_tcp_state_change() already does for the same pattern. | |
| Title | net/rds: use wq_has_sleeper() in rds_cong_map_updated() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Subscriptions
Weaknesses
