Bug 2427125 (CVE-2025-68762)

Summary: CVE-2025-68762 kernel: net: netpoll: initialize work queue before error checks
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A kernel warning vulnerability was found in the Linux kernel's netpoll subsystem. When netconsole setup fails on devices with the IFF_DISABLE_NETPOLL flag, the cleanup path calls cancel_work_sync() on an uninitialized work queue. This triggers a kernel warning at workqueue.c due to attempting to flush an uninitialized work structure.
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Description OSIDB Bzimport 2026-01-05 10:02:57 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: netpoll: initialize work queue before error checks

Prevent a kernel warning when netconsole setup fails on devices with
IFF_DISABLE_NETPOLL flag. The warning (at kernel/workqueue.c:4242 in
__flush_work) occurs because the cleanup path tries to cancel an
uninitialized work queue.

When __netpoll_setup() encounters a device with IFF_DISABLE_NETPOLL,
it fails early and calls skb_pool_flush() for cleanup. This function
calls cancel_work_sync(&np->refill_wq), but refill_wq hasn't been
initialized yet, triggering the warning.

Move INIT_WORK() to the beginning of __netpoll_setup(), ensuring the
work queue is properly initialized before any potential failure points.
This allows the cleanup path to safely cancel the work queue regardless
of where the setup fails.
Comment 1 Vipul Nair 2026-01-05 10:26:37 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026010551-CVE-2025-68762-8b05@gregkh/T