Re: [KVM] fdd90b978b: WARNING:suspicious_RCU_usage

From: David Woodhouse
Date: Tue Dec 22 2020 - 04:43:14 EST


On Tue, 2020-12-22 at 13:06 +0800, kernel test robot wrote:
>
> kern :warn : [ 86.138096] WARNING: suspicious RCU usage
> kern :warn : [ 86.142286] 5.10.0-rc5-gfdd90b978b4e #1 Tainted: G I
> kern :warn : [ 86.148879] -----------------------------
> kern :warn : [ 86.153110] include/linux/kvm_host.h:633 suspicious rcu_dereference_check() usage!
> kern :warn : [ 86.160992]
> other info that might help us debug this:
>
> kern :warn : [ 86.169413]
> rcu_scheduler_active = 2, debug_locks = 1
> kern :warn : [ 86.176231] no locks held by xen_shinfo_test/10611.
> kern :warn : [ 86.181328]
> stack backtrace:
> kern :warn : [ 86.185946] CPU: 2 PID: 10611 Comm: xen_shinfo_test Tainted: G I 5.10.0-rc5-gfdd90b978b4e #1
> kern :warn : [ 86.196092] Hardware name: /NUC6i7KYB, BIOS KYSKLi70.86A.0041.2016.0817.1130 08/17/2016
> kern :warn : [ 86.204517] Call Trace:
> kern :warn : [ 86.207122] dump_stack+0x8d/0xb5
> kern :warn : [ 86.210615] kvm_map_gfn+0xbb/0xc0
> kern :warn : [ 86.214127] kvm_xen_map_guest_page+0x5c/0x100
> kern :warn : [ 86.218787] kvm_xen_hvm_set_attr+0xf8/0x1c0
> kern :warn : [ 86.223275] kvm_arch_vm_ioctl+0xae9/0xc80


Thanks. FWIW all this mapping code was removed in the last version of
the series.

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