CVE-2021-47217

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> x86/hyperv: Fix NULL deref in set_hv_tscchange_cb() if Hyper-V setup fails<br /> <br /> Check for a valid hv_vp_index array prior to derefencing hv_vp_index when<br /> setting Hyper-V&amp;#39;s TSC change callback. If Hyper-V setup failed in<br /> hyperv_init(), the kernel will still report that it&amp;#39;s running under<br /> Hyper-V, but will have silently disabled nearly all functionality.<br /> <br /> BUG: kernel NULL pointer dereference, address: 0000000000000010<br /> #PF: supervisor read access in kernel mode<br /> #PF: error_code(0x0000) - not-present page<br /> PGD 0 P4D 0<br /> Oops: 0000 [#1] SMP<br /> CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc2+ #75<br /> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015<br /> RIP: 0010:set_hv_tscchange_cb+0x15/0xa0<br /> Code: 04 82 8b 15 12 17 85 01 48 c1 e0 20 48 0d ee 00 01 00 f6 c6 08<br /> ...<br /> Call Trace:<br /> kvm_arch_init+0x17c/0x280<br /> kvm_init+0x31/0x330<br /> vmx_init+0xba/0x13a<br /> do_one_initcall+0x41/0x1c0<br /> kernel_init_freeable+0x1f2/0x23b<br /> kernel_init+0x16/0x120<br /> ret_from_fork+0x22/0x30