From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>, Peter Xu <peterx@redhat.com>
Cc: Nikunj A Dadhania <nikunj@amd.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
vasant.hegde@amd.com, brijesh.singh@amd.com
Subject: Re: [PATCH v2] KVM: x86: Check for rmaps allocation
Date: Fri, 7 Jan 2022 18:04:09 +0100 [thread overview]
Message-ID: <f070a443-9763-a62f-38ef-3398fa942465@redhat.com> (raw)
In-Reply-To: <Ydhx1qguxVZxOGfo@google.com>
On 1/7/22 18:01, Sean Christopherson wrote:
> On Wed, Jan 05, 2022, Peter Xu wrote:
>> On Wed, Jan 05, 2022 at 09:33:37AM +0530, Nikunj A Dadhania wrote:
>>> With TDP MMU being the default now, access to mmu_rmaps_stat debugfs
>>> file causes following oops:
>>>
>>> BUG: kernel NULL pointer dereference, address: 0000000000000000
>>> PGD 0 P4D 0
>>> Oops: 0000 [#1] PREEMPT SMP NOPTI
>>> CPU: 7 PID: 3185 Comm: cat Not tainted 5.16.0-rc4+ #204
>>> RIP: 0010:pte_list_count+0x6/0x40
>>> Call Trace:
>>> <TASK>
>>> ? kvm_mmu_rmaps_stat_show+0x15e/0x320
>>> seq_read_iter+0x126/0x4b0
>>> ? aa_file_perm+0x124/0x490
>>> seq_read+0xf5/0x140
>>> full_proxy_read+0x5c/0x80
>>> vfs_read+0x9f/0x1a0
>>> ksys_read+0x67/0xe0
>>> __x64_sys_read+0x19/0x20
>>> do_syscall_64+0x3b/0xc0
>>> entry_SYSCALL_64_after_hwframe+0x44/0xae
>>> RIP: 0033:0x7fca6fc13912
>>>
>>> Return early when rmaps are not present.
>>>
>>> Reported-by: Vasant Hegde <vasant.hegde@amd.com>
>>> Tested-by: Vasant Hegde <vasant.hegde@amd.com>
>>> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
>>> ---
>
> Reviewed-by: Sean Christopherson <seanjc@google.com>
>
Queued, thanks.
Paolo
next prev parent reply other threads:[~2022-01-07 17:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-05 4:03 Nikunj A Dadhania
2022-01-05 9:07 ` Peter Xu
2022-01-07 17:01 ` Sean Christopherson
2022-01-07 17:03 ` Paolo Bonzini
2022-01-07 17:04 ` Paolo Bonzini [this message]
2022-01-07 17:08 ` Paolo Bonzini
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