From: Gaurav Kohli Date: Sat, 26 Nov 2022 06:14:51 +0000 (-0800) Subject: x86/hyperv: Remove unregister syscore call from Hyper-V cleanup X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=32c97d980e2eef25465d453f2956a9ca68926a3c;p=linux.git x86/hyperv: Remove unregister syscore call from Hyper-V cleanup Hyper-V cleanup code comes under panic path where preemption and irq is already disabled. So calling of unregister_syscore_ops might schedule out the thread even for the case where mutex lock is free. hyperv_cleanup unregister_syscore_ops mutex_lock(&syscore_ops_lock) might_sleep Here might_sleep might schedule out this thread, where voluntary preemption config is on and this thread will never comes back. And also this was added earlier to maintain the symmetry which is not required as this can comes during crash shutdown path only. To prevent the same, removing unregister_syscore_ops function call. Signed-off-by: Gaurav Kohli Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1669443291-2575-1-git-send-email-gauravkohli@linux.microsoft.com Signed-off-by: Wei Liu --- diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index a823fde1ad7f3..41ef036ebb7ba 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -537,8 +537,6 @@ void hyperv_cleanup(void) union hv_x64_msr_hypercall_contents hypercall_msr; union hv_reference_tsc_msr tsc_msr; - unregister_syscore_ops(&hv_syscore_ops); - /* Reset our OS id */ wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0); hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);