From: JiaHong Su <s11242586@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [BUG] KVM: hung task during vCPU destruction in kvm_clear_async_pf_completion_queue()
Date: Sat, 10 Jan 2026 03:45:36 +0800 [thread overview]
Message-ID: <69615ae2.050a0220.47ba6.c4aa@mx.google.com> (raw)
Hello,
I found the following issue using Syzkaller on:
HEAD commit: 9ace475 Linux 6.19-rc4
Kernel config: https://gist.github.com/AxelHowe/7fb5b3917d2f4a18c1d8cefbfd5846ef
A hung task warning is reported during KVM vCPU destruction.
INFO: task repro:9778 blocked for more than 143 seconds.
Not tainted 6.19.0-rc4 #8
Blocked by coredump.
Call Trace:
__schedule
schedule
schedule_timeout
__wait_for_common
__flush_work
cancel_work_sync
kvm_clear_async_pf_completion_queue
kvm_arch_vcpu_destroy
kvm_destroy_vcpus
kvm_arch_destroy_vm
kvm_put_kvm
kvm_vcpu_release
__fput
task_work_run
do_exit
do_group_exit
get_signal
arch_do_signal_or_restart
entry_SYSCALL_64_after_hwframe
The teardown path blocks in cancel_work_sync() while clearing the async
page fault completion queue. The wait exceeds the hung task timeout and
does not appear to make forward progress in this exit/coredump context.
C reproducer, full dmesg output are available at:
https://gist.github.com/AxelHowe/f09bce07178d13a2ee095f30eef8327e
Thanks,
JiaHong Su
reply other threads:[~2026-01-09 19:45 UTC|newest]
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