CVE-2026-80997

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

net: ipa: fix stalled modem TX queue after runtime resume

ipa_start_xmit() unconditionally stops the TX queue before calling

pm_runtime_get(), relying on the wake scheduled by runtime resume

(ipa_modem_wake_queue_work()) to restart it once power is ACTIVE.

But that work is queued from within the runtime resume callback,

before the device's power state reaches RPM_ACTIVE, so it can run

while the device is still RPM_RESUMING. The wake is then consumed

too early: the transmit it restarts stops the queue again,

pm_runtime_get() returns -EINPROGRESS without arranging any future

wake (deferred_resume exists only for RPM_SUSPENDING), and after the

resume completes nothing is left to wake the queue. Transmit stalls

permanently: packets pile up in the qdisc behind the stopped queue,

the device runtime-suspends, and since the netdev registers no

ndo_tx_timeout the watchdog never fires. Observed on SM7635

(Fairphone 6) as the cellular data path going permanently deaf

within hours, RX included, since nothing resumes the suspended

endpoints.

Close the window by making the wake work wait for the resume to

complete (pm_runtime_get_sync()) before waking the queue. Every

queue stop is then guaranteed a later wake that happens while power

is ACTIVE; a transmit racing a new suspend/resume cycle re-schedules

the work. If the device could not be resumed, wake the queue anyway

so pending packets are dropped by the transmit path rather than

stranded.

The STARTED power flag used to narrow this window: a wake running

before the transmit path's stop suppressed that stop, but only once,

as the flag was cleared by the first stop it absorbed. Removing the

flag made a single transmit during an in-flight resume sufficient to

strand the queue, which is the form observed.

With an accelerated reproducer (autosuspend delay shortened to 5 ms,

~20 packets/s of TX), an unpatched kernel stalled three times in

230 s / 4380 packets; with this patch the same test ran 3601 s /

70298 packets without a stall.