From dfe94d4086e40e92b1926bddcefa629b791e9b28 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Mon, 21 Dec 2020 22:55:41 -0800 Subject: x86/hyperv: Fix kexec panic/hang issues Currently the kexec kernel can panic or hang due to 2 causes: 1) hv_cpu_die() is not called upon kexec, so the hypervisor corrupts the old VP Assist Pages when the kexec kernel runs. The same issue is fixed for hibernation in commit 421f090c819d ("x86/hyperv: Suspend/resume the VP assist page for hibernation"). Now fix it for kexec. 2) hyperv_cleanup() is called too early. In the kexec path, the other CPUs are stopped in hv_machine_shutdown() -> native_machine_shutdown(), so between hv_kexec_handler() and native_machine_shutdown(), the other CPUs can still try to access the hypercall page and cause panic. The workaround "hv_hypercall_pg = NULL;" in hyperv_cleanup() is unreliabe. Move hyperv_cleanup() to a better place. Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20201222065541.24312-1-decui@microsoft.com Signed-off-by: Wei Liu --- drivers/hv/vmbus_drv.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'drivers/hv') diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 502f8cd95f6d..d491fdcee61f 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2550,7 +2550,6 @@ static void hv_kexec_handler(void) /* Make sure conn_state is set as hv_synic_cleanup checks for it */ mb(); cpuhp_remove_state(hyperv_cpuhp_online); - hyperv_cleanup(); }; static void hv_crash_handler(struct pt_regs *regs) @@ -2566,7 +2565,6 @@ static void hv_crash_handler(struct pt_regs *regs) cpu = smp_processor_id(); hv_stimer_cleanup(cpu); hv_synic_disable_regs(cpu); - hyperv_cleanup(); }; static int hv_synic_suspend(void) -- cgit v1.2.3-70-g09d2