wanpeng li c9dfd3fb08 KVM: nVMX: Hold KVM's srcu lock when syncing vmcs12->shadow ... For the duration of mapping eVMCS, it derefences ->memslots without holding ->srcu or ->slots_lock when accessing hv assist page. This patch fixes it by moving nested_sync_vmcs12_to_shadow to prepare_guest_switch, where the SRCU is already taken. It can be reproduced by running kvm's evmcs_test selftest. ============================= warning: suspicious rcu usage 5.6.0-rc1+ #53 tainted: g w ioe ----------------------------- ./include/linux/kvm_host.h:623 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by evmcs_test/8507: #0: ffff9ddd156d00d0 (&vcpu->mutex){+.+.}, at: kvm_vcpu_ioctl+0x85/0x680 [kvm] stack backtrace: cpu: 6 pid: 8507 comm: evmcs_test tainted: g w ioe 5.6.0-rc1+ #53 hardware name: dell inc. optiplex 7040/0jctf8, bios 1.4.9 09/12/2016 call trace: dump_stack+0x68/0x9b kvm_read_guest_cached+0x11d/0x150 [kvm] kvm_hv_get_assist_page+0x33/0x40 [kvm] nested_enlightened_vmentry+0x2c/0x60 [kvm_intel] nested_vmx_handle_enlightened_vmptrld.part.52+0x32/0x1c0 [kvm_intel] nested_sync_vmcs12_to_shadow+0x439/0x680 [kvm_intel] vmx_vcpu_run+0x67a/0xe60 [kvm_intel] vcpu_enter_guest+0x35e/0x1bc0 [kvm] kvm_arch_vcpu_ioctl_run+0x40b/0x670 [kvm] kvm_vcpu_ioctl+0x370/0x680 [kvm] ksys_ioctl+0x235/0x850 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x77/0x780 entry_syscall_64_after_hwframe+0x49/0xbe Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2020-02-21 18:05:03 +01:00
..
boot	Kbuild updates for v5.6 (2nd)	2020-02-09 16:05:50 -08:00
configs
crypto
entry	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
events
hyperv	x86/hyperv: Suspend/resume the hypercall page for hibernation	2020-02-01 09:41:16 +01:00
ia32
include	kvm/emulate: fix a -Werror=cast-function-type	2020-02-20 18:13:45 +01:00
kernel	A set of fixes for X86:	2020-02-09 12:11:12 -08:00
kvm	KVM: nVMX: Hold KVM's srcu lock when syncing vmcs12->shadow	2020-02-21 18:05:03 +01:00
lib	Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2020-01-31 11:05:33 -08:00
math-emu
mm	x86: mm: avoid allocating struct mm_struct on the stack	2020-02-04 03:05:25 +00:00
net
oprofile
pci	pci-v5.6-changes	2020-01-31 14:48:54 -08:00
platform	A single fix for a EFI boot regression on X86 which was caused by the	2020-02-09 11:54:50 -08:00
power
purgatory
ras
realmode	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
tools	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
um
video
xen	A set of fixes for X86:	2020-02-09 12:11:12 -08:00
.gitignore
Kbuild
Kconfig	asm-generic/tlb: rename HAVE_RCU_TABLE_FREE	2020-02-04 03:05:26 +00:00
Kconfig.cpu
Kconfig.debug	x86: mm: convert dump_pagetables to use walk_page_range	2020-02-04 03:05:25 +00:00
Makefile
Makefile_32.cpu
Makefile.um