Greeting, FYI, we noticed the following commit (built with gcc-9): commit: 19b4a474364435a929b1e377a290636cba89cebd ("KVM: x86: declare Xen HVM shared info capability and add test case") url: https://github.com/0day-ci/linux/commits/David-Woodhouse/KVM-Add-minimal-support-for-Xen-HVM-guests/20210112-040054 in testcase: kernel-selftests version: kernel-selftests-x86_64-cb0debfe-1_20201231 with following parameters: group: kvm ucode: 0xe2 test-description: The kernel contains a set of "self tests" under the tools/testing/selftests/ directory. These are intended to be small unit tests to exercise individual code paths in the kernel. test-url: https://www.kernel.org/doc/Documentation/kselftest.txt on test machine: 8 threads Intel(R) Core(TM) i7-6770HQ CPU @ 2.60GHz with 32G memory caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): If you fix the issue, kindly add following tag Reported-by: kernel test robot [ 98.013319] WARNING: suspicious RCU usage [ 98.017738] 5.11.0-rc3-g19b4a4743644 #1 Tainted: G W I [ 98.024397] ----------------------------- [ 98.028742] include/linux/kvm_host.h:641 suspicious rcu_dereference_check() usage! [ 98.036741] [ 98.036741] other info that might help us debug this: [ 98.036741] [ 98.045216] [ 98.045216] rcu_scheduler_active = 2, debug_locks = 1 [ 98.052156] no locks held by xen_shinfo_test/10670. [ 98.057387] [ 98.057387] stack backtrace: [ 98.062104] CPU: 4 PID: 10670 Comm: xen_shinfo_test Tainted: G W I 5.11.0-rc3-g19b4a4743644 #1 [ 98.072421] Hardware name: /NUC6i7KYB, BIOS KYSKLi70.86A.0041.2016.0817.1130 08/17/2016 [ 98.080909] Call Trace: [ 98.083465] dump_stack (kbuild/src/consumer/lib/dump_stack.c:122) [ 98.086928] kvm_gfn_to_hva_cache_init (kbuild/src/consumer/include/linux/kvm_host.h:641 kbuild/src/consumer/include/linux/kvm_host.h:638 kbuild/src/consumer/include/linux/kvm_host.h:648 kbuild/src/consumer/arch/x86/kvm/../../../virt/kvm/kvm_main.c:2557) [ 98.091791] kvm_xen_hvm_set_attr (kbuild/src/consumer/arch/x86/kvm/xen.c:28 kbuild/src/consumer/arch/x86/kvm/xen.c:194) [ 98.096277] kvm_arch_vm_ioctl (kbuild/src/consumer/arch/x86/kvm/x86.c:5664) [ 98.100577] ? preempt_count_sub (kbuild/src/consumer/kernel/sched/core.c:4737 kbuild/src/consumer/kernel/sched/core.c:4734 kbuild/src/consumer/kernel/sched/core.c:4756) [ 98.104948] ? _raw_spin_unlock (kbuild/src/consumer/arch/x86/include/asm/preempt.h:102 kbuild/src/consumer/include/linux/spinlock_api_smp.h:152 kbuild/src/consumer/kernel/locking/spinlock.c:183) [ 98.109145] ? do_fault (kbuild/src/consumer/mm/memory.c:3998 kbuild/src/consumer/mm/memory.c:4014 kbuild/src/consumer/mm/memory.c:4147) [ 98.112910] kvm_vm_ioctl (kbuild/src/consumer/arch/x86/kvm/../../../virt/kvm/kvm_main.c:3977) [ 98.116783] ? find_held_lock (kbuild/src/consumer/kernel/locking/lockdep.c:4935) [ 98.120799] __x64_sys_ioctl (kbuild/src/consumer/fs/ioctl.c:49 kbuild/src/consumer/fs/ioctl.c:753 kbuild/src/consumer/fs/ioctl.c:739 kbuild/src/consumer/fs/ioctl.c:739) [ 98.124720] do_syscall_64 (kbuild/src/consumer/arch/x86/entry/common.c:46) [ 98.128455] entry_SYSCALL_64_after_hwframe (kbuild/src/consumer/arch/x86/entry/entry_64.S:127) [ 98.133804] RIP: 0033:0x7f2b026d9427 [ 98.137579] Code: 00 00 90 48 8b 05 69 aa 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 39 aa 0c 00 f7 d8 64 89 01 48 All code ======== 0: 00 00 add %al,(%rax) 2: 90 nop 3: 48 8b 05 69 aa 0c 00 mov 0xcaa69(%rip),%rax # 0xcaa73 a: 64 c7 00 26 00 00 00 movl $0x26,%fs:(%rax) 11: 48 c7 c0 ff ff ff ff mov $0xffffffffffffffff,%rax 18: c3 retq 19: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 20: 00 00 00 23: b8 10 00 00 00 mov $0x10,%eax 28: 0f 05 syscall 2a:* 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax <-- trapping instruction 30: 73 01 jae 0x33 32: c3 retq 33: 48 8b 0d 39 aa 0c 00 mov 0xcaa39(%rip),%rcx # 0xcaa73 3a: f7 d8 neg %eax 3c: 64 89 01 mov %eax,%fs:(%rcx) 3f: 48 rex.W Code starting with the faulting instruction =========================================== 0: 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax 6: 73 01 jae 0x9 8: c3 retq 9: 48 8b 0d 39 aa 0c 00 mov 0xcaa39(%rip),%rcx # 0xcaa49 10: f7 d8 neg %eax 12: 64 89 01 mov %eax,%fs:(%rcx) 15: 48 rex.W [ 98.157411] RSP: 002b:00007ffdab1fda68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 98.165374] RAX: ffffffffffffffda RBX: 000000004028aec9 RCX: 00007f2b026d9427 [ 98.172912] RDX: 00007ffdab1fdad0 RSI: 000000004028aec9 RDI: 0000000000000006 [ 98.180388] RBP: 0000000000000004 R08: 000000000040bf70 R09: 000000004028aec9 [ 98.187919] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000401840 [ 98.195359] R13: 00007ffdab1fdce0 R14: 0000000000000000 R15: 0000000000000000 [ 106.803873] gcc -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 -fno-stack-protector -fno-PIE -I../../../../tools/include -I../../../../tools/arch/x86/include -I../../../../usr/include/ -Iinclude -Ix86_64 -Iinclude/x86_64 -I.. -pthread -no-pie x86_64/cr4_cpuid_sync_test.c /usr/src/perf_selftests-x86_64-rhel-7.6-kselftests-19b4a474364435a929b1e377a290636cba89cebd/tools/testing/selftests/kvm/libkvm.a -o /usr/src/perf_selftests-x86_64-rhel-7.6-kselftests-19b4a474364435a929b1e377a290636cba89cebd/tools/testing/selftests/kvm/x86_64/cr4_cpuid_sync_test [ 106.803882] [ 121.988033] gcc -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 -fno-stack-protector -fno-PIE -I../../../../tools/include -I../../../../tools/arch/x86/include -I../../../../usr/include/ -Iinclude -Ix86_64 -Iinclude/x86_64 -I.. -pthread -no-pie x86_64/evmcs_test.c /usr/src/perf_selftests-x86_64-rhel-7.6-kselftests-19b4a474364435a929b1e377a290636cba89cebd/tools/testing/selftests/kvm/libkvm.a -o /usr/src/perf_selftests-x86_64-rhel-7.6-kselftests-19b4a474364435a929b1e377a290636cba89cebd/tools/testing/selftests/kvm/x86_64/evmcs_test [ 121.988042] [ 136.292354] gcc -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 -fno-stack-protector -fno-PIE -I../../../../tools/include -I../../../../tools/arch/x86/include -I../../../../usr/include/ -Iinclude -Ix86_64 -Iinclude/x86_64 -I.. -pthread -no-pie x86_64/hyperv_cpuid.c /usr/src/perf_selftests-x86_64-rhel-7.6-kselftests-19b4a474364435a929b1e377a290636cba89cebd/tools/testing/selftests/kvm/libkvm.a -o /usr/src/perf_selftests-x86_64-rhel-7.6-kselftests-19b4a474364435a929b1e377a290636cba89cebd/tools/testing/selftests/kvm/x86_64/hyperv_cpuid [ 136.292364] To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp install job.yaml # job file is attached in this email bin/lkp run job.yaml Thanks, Oliver Sang