In the Linux kernel, the following vulnerability has been resolved:
net: decrease cached dst counters in dst_release
Upstream fix ac888d58869b ("net: do not delay dstentriesadd() in dstrelease()") moved decrementing the dst count from dstdestroy to dstrelease to avoid accessing already freed data in case of netns dismantle. However in case CONFIGDST_CACHE is enabled and OvS+tunnels are used, this fix is incomplete as the same issue will be seen for cached dsts:
Unable to handle kernel paging request at virtual address ffff5aabf6b5c000 Call trace: percpucounteraddbatch+0x3c/0x160 (P) dstrelease+0xec/0x108 dstcachedestroy+0x68/0xd8 dstdestroy+0x13c/0x168 dstdestroyrcu+0x1c/0xb0 rcudobatch+0x18c/0x7d0 rcucore+0x174/0x378 rcucoresi+0x18/0x30
Fix this by invalidating the cache, and thus decrementing cached dst counters, in dst_release too.