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KVM: Fix lockdep false negative during host resume
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I saw the below splatting after the host suspended and resumed.

   WARNING: CPU: 0 PID: 2943 at kvm/arch/x86/kvm/../../../virt/kvm/kvm_main.c:5531 kvm_resume+0x2c/0x30 [kvm]
   CPU: 0 PID: 2943 Comm: step_after_susp Tainted: G        W IOE     5.17.0-rc3+ #4
   RIP: 0010:kvm_resume+0x2c/0x30 [kvm]
   Call Trace:
    <TASK>
    syscore_resume+0x90/0x340
    suspend_devices_and_enter+0xaee/0xe90
    pm_suspend.cold+0x36b/0x3c2
    state_store+0x82/0xf0
    kernfs_fop_write_iter+0x1b6/0x260
    new_sync_write+0x258/0x370
    vfs_write+0x33f/0x510
    ksys_write+0xc9/0x160
    do_syscall_64+0x3b/0xc0
    entry_SYSCALL_64_after_hwframe+0x44/0xae

lockdep_is_held() can return -1 when lockdep is disabled which triggers
this warning. Let's use lockdep_assert_not_held() which can detect
incorrect calls while holding a lock and it also avoids false negatives
when lockdep is disabled.

Signed-off-by: Wanpeng Li <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
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Wanpeng Li authored and bonzini committed Feb 17, 2022
1 parent 127770a commit 4cb9a99
Showing 1 changed file with 1 addition and 3 deletions.
4 changes: 1 addition & 3 deletions virt/kvm/kvm_main.c
Original file line number Diff line number Diff line change
Expand Up @@ -5528,9 +5528,7 @@ static int kvm_suspend(void)
static void kvm_resume(void)
{
if (kvm_usage_count) {
#ifdef CONFIG_LOCKDEP
WARN_ON(lockdep_is_held(&kvm_count_lock));
#endif
lockdep_assert_not_held(&kvm_count_lock);
hardware_enable_nolock(NULL);
}
}
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