Linux hv driver: prevent infinite retry loop in init_vp_index
CVE-2026-99251 Published on November 3, 2026
Drivers: hv: Avoid infinite retry loop in init_vp_index()
In the Linux kernel, the following vulnerability has been resolved:
Drivers: hv: Avoid infinite retry loop in init_vp_index()
There is a retry loop in init_vp_index() where the CPUs from a certain
node are stripped out if they have already been in the allocated cpumask
or not in HK_TYPE_MANAGED_IRQ housekeeping cpumask. If there is no
CPU left, the allocated cpumask is ignored and the process is retried
again. However, if the HK_TYPE_MANAGED_IRQ housekeeping cpumask turns
out not to contain any CPU in that particular node, that will become an
infinite retry loop. This particular problem was reported by sashiko
[1]. This should rarely happen, but we still need to guard against this.
Fix this infinite loop problem by also skipping NUMA node that has no
housekeeping CPU in the inner while loop of init_vp_index(). Also update
the early abort check to check for the absence of online housekeeping
CPUs instead of just the emptiness of the cpumask. As the outer for
loop will only be reached if the housekeeping cpumask has at least one
online CPU, a NUMA node with housekeeping CPUs will eventually be found.
Products Associated with CVE-2026-99251
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Affected Versions
Linux:- Version 6640b5df1a38801be6d0595c8cd2177d968d7ee0 and below b3993f6dc106ff416c7a613c631e1e0af451aed7 is affected.
- Version 6640b5df1a38801be6d0595c8cd2177d968d7ee0 and below f561392afb44a8a42c54c1cfd3f33dace0b50537 is affected.
- Version 6640b5df1a38801be6d0595c8cd2177d968d7ee0 and below 15dd3429f0e76ca071657e480cb7e6ff3a1af730 is affected.
- Version 6640b5df1a38801be6d0595c8cd2177d968d7ee0 and below 7141331f2d245efc07175802a6bf76badec871ed is affected.
- Version 6640b5df1a38801be6d0595c8cd2177d968d7ee0 and below 95fec47cdbf747b81ab22affd7252dda6050ad0c is affected.
- Version 6640b5df1a38801be6d0595c8cd2177d968d7ee0 and below 32ea0a33e3a0fb7c10c601b43e1b2f6c06a3f5fd is affected.
- Version 5.19 is affected.
- Before 5.19 is unaffected.
- Version 6.1.191, <= 6.1.* is unaffected.
- Version 6.6.161, <= 6.6.* is unaffected.
- Version 6.12.115, <= 6.12.* is unaffected.
- Version 6.18.59, <= 6.18.* is unaffected.
- Version 7.2.13, <= 7.2.* is unaffected.
- Version 7.3, <= * is unaffected.