FYI, we noticed the following commit: commit: f5caf621ee357279e759c0911daf6d55c7d36f03 ("x86/asm: Fix inline asm call constraints for Clang") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master in testcase: trinity with following parameters: runtime: 300s test-description: Trinity is a linux system call fuzz tester. test-url: http://codemonkey.org.uk/projects/trinity/ on test machine: qemu-system-x86_64 -enable-kvm -m 420M caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +-----------------------------------------+------------+------------+ | | 0d0970eef3 | f5caf621ee | +-----------------------------------------+------------+------------+ | boot_successes | 9 | 4 | | boot_failures | 0 | 4 | | PANIC:double_fault | 0 | 4 | | Kernel_panic-not_syncing:Machine_halted | 0 | 4 | +-----------------------------------------+------------+------------+ [ 7.757440] udevtrigger (130) used greatest stack depth: 12344 bytes left [ 8.262143] procd: - ubus - [ 9.279484] procd: - init - Please press Enter to activate this console. [ 9.349553] find (656) used greatest stack depth: 12296 bytes left [ 10.584905] PANIC: double fault, error_code: 0x0 [ 10.585372] CPU: 0 PID: 917 Comm: netifd Not tainted 4.14.0-rc1-00015-gf5caf62 #2 [ 10.586062] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 10.586978] task: ffff8800141a8000 task.stack: ffffc90000274000 [ 10.587519] RIP: 0010:compat_sock_ioctl+0xfea/0x103e [ 10.587974] RSP: 0000:0000000000277d78 EFLAGS: 00010283 [ 10.588448] RAX: 0000000000277d78 RBX: 0000000000008933 RCX: ffff8800141a8000 [ 10.589103] RDX: 0000000000000020 RSI: 00000000fffbea00 RDI: 00000000fffbea50 [ 10.589757] RBP: ffffc90000277e18 R08: fffbea50fffbea34 R09: ffffffff814a68c9 [ 10.590407] R10: ffffff9c00000002 R11: 00000000fffbea50 R12: 0000000000000000 [ 10.591056] R13: ffff880012c8c880 R14: 00000000fffbea50 R15: 00000000fffbea00 [ 10.591708] FS: 0000000000000000(0000) GS:ffff880019a00000(0063) knlGS:00000000f7fab9a0 [ 10.592446] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 10.592973] CR2: 0000000000277d68 CR3: 000000001807f000 CR4: 00000000000006b0 [ 10.593623] Call Trace: [ 10.593858] Code: 02 0f ff 65 48 8b 04 25 80 d1 00 00 48 8b 80 28 25 00 00 48 83 e8 20 49 39 c7 77 34 89 e0 4c 89 f7 4c 89 fe ba 20 00 00 00 89 c4 b3 52 05 00 85 c0 74 22 eb 1a 4c 89 fa 89 de 4c 89 ef e8 c6 [ 10.595705] Kernel panic - not syncing: Machine halted. [ 10.596181] CPU: 0 PID: 917 Comm: netifd Not tainted 4.14.0-rc1-00015-gf5caf62 #2 [ 10.596868] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 10.597786] Call Trace: [ 10.598017] <#DF> [ 10.598216] dump_stack+0x8f/0xc4 [ 10.598527] panic+0xda/0x22f [ 10.598811] df_debug+0x30/0x30 [ 10.599104] do_double_fault+0x9b/0xaf [ 10.599456] double_fault+0x22/0x30 [ 10.599791] RIP: 0010:compat_sock_ioctl+0xfea/0x103e [ 10.600247] RSP: 0000:0000000000277d78 EFLAGS: 00010283 [ 10.600733] RAX: 0000000000277d78 RBX: 0000000000008933 RCX: ffff8800141a8000 [ 10.601381] RDX: 0000000000000020 RSI: 00000000fffbea00 RDI: 00000000fffbea50 [ 10.602036] RBP: ffffc90000277e18 R08: fffbea50fffbea34 R09: ffffffff814a68c9 [ 10.602700] R10: ffffff9c00000002 R11: 00000000fffbea50 R12: 0000000000000000 [ 10.603349] R13: ffff880012c8c880 R14: 00000000fffbea50 R15: 00000000fffbea00 [ 10.604002] ? dev_ioctl+0x2d7/0x5e3 [ 10.604336] WARNING: kernel stack regs at ffff880019a05f58 in netifd:917 has bad 'bp' value ffffc90000277e18 [ 10.604337] unwind stack type:0 next_sp:0000000000277d78 mask:0x10 graph_idx:0 [ 10.604339] ffff880019a05d48: ffff880019a05e28 (0xffff880019a05e28) [ 10.604340] ffff880019a05d50: ffffffff8100ce27 (show_trace_log_lvl+0x203/0x2a7) [ 10.604342] ffff880019a05d58: ffffffff81473d28 (compat_sock_ioctl+0xfea/0x103e) 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