FYI, we noticed the following commit (built with gcc-6): commit: 5f3cb7eb7ce2d895658c6251fbaa4b59d93d941d ("x86/entry/64: Create a percpu SYSCALL entry trampoline") https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git x86/entry_stack in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -smp 2 -m 512M caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +-------------------------------------------------------+------------+------------+ | | c4b515521d | 5f3cb7eb7c | +-------------------------------------------------------+------------+------------+ | boot_successes | 10 | 0 | | boot_failures | 4 | 14 | | WARNING:possible_circular_locking_dependency_detected | 4 | 6 | | WARNING:suspicious_RCU_usage | 0 | 14 | | arch/x86/kernel/traps.c:#entry_code_didn't_wake_RCU | 0 | 14 | | RIP:rcu_eqs_exit | 0 | 14 | | WARNING:at_kernel/rcu/tree.c:#rcu_eqs_exit | 0 | 14 | | WARNING:at_kernel/sched/cputime.c:#get_vtime_delta | 0 | 14 | | RIP:get_vtime_delta | 0 | 14 | +-------------------------------------------------------+------------+------------+ [ 11.683695] WARNING: suspicious RCU usage [ 11.684103] 4.14.0-12905-g5f3cb7e #2 Not tainted [ 11.684572] ----------------------------- [ 11.684976] arch/x86/kernel/traps.c:289 entry code didn't wake RCU! [ 11.685785] [ 11.685785] other info that might help us debug this: [ 11.685785] [ 11.686579] [ 11.686579] RCU used illegally from idle CPU! [ 11.686579] rcu_scheduler_active = 2, debug_locks = 1 [ 11.687646] RCU used illegally from extended quiescent state! [ 11.688228] no locks held by init/1. [ 11.688587] [ 11.688587] stack backtrace: [ 11.689025] CPU: 1 PID: 1 Comm: init Not tainted 4.14.0-12905-g5f3cb7e #2 [ 11.689697] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 11.690515] Call Trace: [ 11.690776] dump_stack+0xa9/0xf7 [ 11.691116] do_error_trap+0x5a/0x117 [ 11.691495] ? trace_hardirqs_off_caller+0x3b/0x9d [ 11.691975] ? irq_trace+0x2e/0x32 [ 11.692330] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 11.692798] ? time_hardirqs_off+0x12/0x2d [ 11.693222] ? trace_hardirqs_off_caller+0x3b/0x9d [ 11.693704] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 11.694176] ? restore_regs_and_return_to_kernel+0x32/0x32 [ 11.694730] invalid_op+0x1f/0x40 [ 11.695074] RIP: 0010:rcu_eqs_exit+0x45/0x9a [ 11.695778] RSP: 0018:ffffc900000fff10 EFLAGS: 00010086 [ 11.696484] RAX: 000000000000001d RBX: 0000000000000001 RCX: ffff88000029a040 [ 11.697183] RDX: 0000001d0029a040 RSI: ffffffff810ec321 RDI: ffffffff810ea8e9 [ 11.697888] RBP: 0000000000000001 R08: 0000000424d37a7e R09: 0000000000000001 [ 11.698591] R10: 000000000000037f R11: ffff88000029a040 R12: ffff88000029a040 [ 11.699309] R13: 0000000000000000 R14: 0000560473939524 R15: 0000000000001000 [ 11.700013] ? vprintk_func+0x9d/0xa5 [ 11.700392] ? console_unlock+0x4da/0x5cd [ 11.700801] __context_tracking_exit+0x4d/0x1c0 [ 11.701265] enter_from_user_mode+0x55/0x5a [ 11.701689] do_syscall_64+0x23/0x96 [ 11.702052] entry_SYSCALL64_slow_path+0x25/0x25 [ 11.702522] RIP: 0033:0x7ff2ed2e9e7a [ 11.702882] RSP: 002b:00007fffaa6c90a8 EFLAGS: 00000246 ORIG_RAX: 000000000000000c [ 11.703632] RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007ff2ed2e9e7a [ 11.704339] RDX: 0000000000000000 RSI: 00007ff2ed2ee720 RDI: 0000000000000000 [ 11.705039] RBP: 00000000078afbfd R08: 00007fffaa6c9369 R09: 00007fffaa768000 [ 11.705746] R10: 000000000000037f R11: 0000000000000246 R12: 00007fffaa6c9379 [ 11.706456] R13: 0000000000000000 R14: 0000560473939524 R15: 0000000000001000 [ 11.707176] WARNING: CPU: 1 PID: 1 at kernel/rcu/tree.c:962 rcu_eqs_exit+0x45/0x9a [ 11.708231] Modules linked in: [ 11.708547] CPU: 1 PID: 1 Comm: init Not tainted 4.14.0-12905-g5f3cb7e #2 [ 11.709216] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 11.710034] task: ffff88000029a040 task.stack: ffffc900000fc000 [ 11.710629] RIP: 0010:rcu_eqs_exit+0x45/0x9a [ 11.711166] RSP: 0018:ffffc900000fff10 EFLAGS: 00010086 [ 11.711702] RAX: 000000000000001d RBX: 0000000000000001 RCX: ffff88000029a040 [ 11.712406] RDX: 0000001d0029a040 RSI: ffffffff810ec321 RDI: ffffffff810ea8e9 [ 11.713101] RBP: 0000000000000001 R08: 0000000424d37a7e R09: 0000000000000001 [ 11.713805] R10: 000000000000037f R11: ffff88000029a040 R12: ffff88000029a040 [ 11.714534] R13: 0000000000000000 R14: 0000560473939524 R15: 0000000000001000 [ 11.715237] FS: 0000000000000000(0000) GS:ffff88001c400000(0000) knlGS:0000000000000000 [ 11.716026] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 11.716599] CR2: 00007ff2ed2edf3c CR3: 000000000fc24000 CR4: 00000000000006a0 [ 11.717307] Call Trace: [ 11.717569] __context_tracking_exit+0x4d/0x1c0 [ 11.718025] enter_from_user_mode+0x55/0x5a [ 11.718452] do_syscall_64+0x23/0x96 [ 11.718817] entry_SYSCALL64_slow_path+0x25/0x25 [ 11.719283] RIP: 0033:0x7ff2ed2e9e7a [ 11.719645] RSP: 002b:00007fffaa6c90a8 EFLAGS: 00000246 ORIG_RAX: 000000000000000c [ 11.720394] RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007ff2ed2e9e7a [ 11.721092] RDX: 0000000000000000 RSI: 00007ff2ed2ee720 RDI: 0000000000000000 [ 11.721798] RBP: 00000000078afbfd R08: 00007fffaa6c9369 R09: 00007fffaa768000 [ 11.722508] R10: 000000000000037f R11: 0000000000000246 R12: 00007fffaa6c9379 [ 11.723209] R13: 0000000000000000 R14: 0000560473939524 R15: 0000000000001000 [ 11.723911] Code: 01 00 00 00 75 27 83 b8 c4 00 00 00 00 74 1e 80 3d 99 2a 24 01 00 75 15 48 c7 c7 f7 b2 f3 81 c6 05 89 2a 24 01 01 e8 35 ca f9 ff <0f> ff 48 c7 c0 40 0f 1d 00 65 48 03 05 8a cb f0 7e 48 8b 10 48 [ 11.725883] ---[ end trace acb57807445c80ab ]--- To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, Xiaolong