CVE-2026-98070

Status: UPDATED  |  Advisory ID: CVE-2026-98070

Key Details

Affected Products, Subsystems & Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

net/rds: acquire RDS_IN_XMIT in rds_tcp_reset_callbacks()

rds_tcp_reset_callbacks() quiesces the transmit path by setting the

path state to RDS_CONN_RESETTING and then waiting for RDS_IN_XMIT to

be sampled clear before swapping the underlying socket and calling

rds_send_path_reset().

Sampling the bit clear is not the same as owning it: rds_send_xmit()

can re-acquire RDS_IN_XMIT right after the wait_event() returns. Its

state recheck after taking the lock is a store-buffering pattern (the

resetter writes the state and reads the bit, the sender writes the

bit and reads the state) and acquire_in_xmit() is only an acquire

operation, so on weakly ordered architectures both sides can miss

each other's write and the transmit path then runs concurrently with

rds_send_path_reset() rewriting cp_xmit_* state - which is exactly

what the comment above rds_send_path_reset() tells its callers to

prevent.

Take the lock instead, hold it across the socket swap and

rds_send_path_reset(), and release it with a wake-up at the end. The

lock-ordering constraint documented above the wait still holds: the

lock is acquired before lock_sock(), so a sender inside tcp_sendmsg()

can never be waited on while we hold the socket lock.

Two details of the old code go away with the same change:

- t_sock is now read only after the lock is acquired. The old code

cached it before waiting; the teardown in rds_conn_shutdown()

releases that socket and clears t_sock, so a pointer cached before

the wait can be stale by the time the accept path resumes. Reading

it under RDS_IN_XMIT is what makes the exclusion complete once the

teardown owns the same lock, which the next patch arranges; until

then the teardown still only samples the bit, and the two paths

remain as exposed to each other as they are today.

- The old !osock early path called rds_send_path_reset() with no

serialization at all. It now runs under the lock like the normal

path. The conditional RDS_CONN_RESETTING transition of the

previous patch happens before the socket check either way: a path

found without a socket is either still connecting (its reconnect

worker blocked on t_conn_path_lock) and legitimately goes

RESETTING -> UP on the new socket, or it has been torn down

meanwhile and is dropped.

The in-function comment describing the old wait-based quiesce is

rewritten to describe the lock-based one, and the stale block comment

above the function (which still described a return value and an

incomplete list of t_sock writers) is refreshed to name all four

writers - the connect, accept, teardown and swap paths - and what

serializes each of them. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References