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| author |   Wanpeng Li <wanpengli@tencent.com> | 2020-03-02 15:15:36 +0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2020-03-02 17:06:52 +0100 |
| commit | 9a11997e757bcf716c1b199ea7bd1abbadc4b357 (patch) | |
| tree | fa619acfe3650463b0842abdc2cd807c2295b845 /arch/x86/kvm/x86.c | |
| parent | KVM: VMX: check descriptor table exits on instruction emulation (diff) | |
| download | linux-dev-9a11997e757bcf716c1b199ea7bd1abbadc4b357.tar.xz linux-dev-9a11997e757bcf716c1b199ea7bd1abbadc4b357.zip | |
KVM: X86: Fix dereference null cpufreq policy
Naresh Kamboju reported:
Linux version 5.6.0-rc4 (oe-user@oe-host) (gcc version
(GCC)) #1 SMP Sun Mar 1 22:59:08 UTC 2020
kvm: no hardware support
BUG: kernel NULL pointer dereference, address: 000000000000028c
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP NOPTI
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc4 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
04/01/2014
RIP: 0010:kobject_put+0x12/0x1c0
Call Trace:
cpufreq_cpu_put+0x15/0x20
kvm_arch_init+0x1f6/0x2b0
kvm_init+0x31/0x290
? svm_check_processor_compat+0xd/0xd
? svm_check_processor_compat+0xd/0xd
svm_init+0x21/0x23
do_one_initcall+0x61/0x2f0
? rdinit_setup+0x30/0x30
? rcu_read_lock_sched_held+0x4f/0x80
kernel_init_freeable+0x219/0x279
? rest_init+0x250/0x250
kernel_init+0xe/0x110
ret_from_fork+0x27/0x50
Modules linked in:
CR2: 000000000000028c
---[ end trace 239abf40c55c409b ]---
RIP: 0010:kobject_put+0x12/0x1c0
cpufreq policy which is get by cpufreq_cpu_get() can be NULL if it is failure,
this patch takes care of it.
Fixes: aaec7c03de (KVM: x86: avoid useless copy of cpufreq policy)
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kvm/x86.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5de200663f51..3156e25b0774 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7195,10 +7195,12 @@ static void kvm_timer_init(void) cpu = get_cpu(); policy = cpufreq_cpu_get(cpu); - if (policy && policy->cpuinfo.max_freq) - max_tsc_khz = policy->cpuinfo.max_freq; + if (policy) { + if (policy->cpuinfo.max_freq) + max_tsc_khz = policy->cpuinfo.max_freq; + cpufreq_cpu_put(policy); + } put_cpu(); - cpufreq_cpu_put(policy); #endif cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); |