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authorSean Christopherson <seanjc@google.com>2021-11-04 18:22:38 +0000
committerWei Liu <wei.liu@kernel.org>2021-11-15 12:37:08 +0000
commitdaf972118c517b91f74ff1731417feb4270625a4 (patch)
tree621cc7939acb20f966290467e901957fa67303a7 /arch/x86/hyperv
parent8a7eb2d476c6823cd44d8c25a6230a52417d7ef8 (diff)
x86/hyperv: Fix NULL deref in set_hv_tscchange_cb() if Hyper-V setup fails
Check for a valid hv_vp_index array prior to derefencing hv_vp_index when setting Hyper-V's TSC change callback. If Hyper-V setup failed in hyperv_init(), the kernel will still report that it's running under Hyper-V, but will have silently disabled nearly all functionality. BUG: kernel NULL pointer dereference, address: 0000000000000010 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc2+ #75 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:set_hv_tscchange_cb+0x15/0xa0 Code: <8b> 04 82 8b 15 12 17 85 01 48 c1 e0 20 48 0d ee 00 01 00 f6 c6 08 ... Call Trace: kvm_arch_init+0x17c/0x280 kvm_init+0x31/0x330 vmx_init+0xba/0x13a do_one_initcall+0x41/0x1c0 kernel_init_freeable+0x1f2/0x23b kernel_init+0x16/0x120 ret_from_fork+0x22/0x30 Fixes: 93286261de1b ("x86/hyperv: Reenlightenment notifications support") Cc: stable@vger.kernel.org Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Link: https://lore.kernel.org/r/20211104182239.1302956-2-seanjc@google.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'arch/x86/hyperv')
-rw-r--r--arch/x86/hyperv/hv_init.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 24f4a06ac46a..7d252a58fbe4 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -177,6 +177,9 @@ void set_hv_tscchange_cb(void (*cb)(void))
return;
}
+ if (!hv_vp_index)
+ return;
+
hv_reenlightenment_cb = cb;
/* Make sure callback is registered before we write to MSRs */