Comment 12 for bug 1605843

Ping on the issue. I now also managed to trigger it while setting a very simple systemtap probe:

probe kernel.function("generic_fillattr") {
 printf("Uid in inode: %u gid: %u\n", $inode->i_uid->val, $inode->i_gid->val);
}

Running this resulted in:

[854807.910390] invalid opcode: 0000 [#1] SMP
[854807.911398] CPU: 6 PID: 1 Comm: systemd Tainted: G OE 4.4.0-31-generic #50-Ubuntu
[854807.911436] Hardware name: Dell Inc. Precision T1650/0X9M3X, BIOS A20 12/21/2015
[854807.911469] task: ffff88040be58000 ti: ffff88040be60000 task.ti: ffff88040be60000
[854807.911503] RIP: 0010:[<ffffffff818302a8>] [<ffffffff818302a8>] ftrace_stub+0x0/0x8
[854807.911544] RSP: 0018:ffff88040be63e50 EFLAGS: 00010246
[854807.911569] RAX: 0000000000000000 RBX: ffff880405bcf410 RCX: ffff88040378c6c0
[854807.911611] RDX: ffff88040d891b60 RSI: ffff88040be63ec0 RDI: ffff88014b51dd78
[854807.911632] RBP: ffff88040be63e60 R08: ffff88014b51dd78 R09: ffff88040be63e20
[854807.911672] R10: 00007fc4541498c0 R11: 0000000000000000 R12: ffff88040be63ec0
[854807.911703] R13: ffff88040be63ec0 R14: 0000000000000000 R15: 000055de063aff00
[854807.911736] FS: 00007fc4541498c0(0000) GS:ffff88041e380000(0000) knlGS:0000000000000000
[854807.911771] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[854807.911797] CR2: 00007f891558de00 CR3: 0000000405a4e000 CR4: 00000000001406e0
[854807.911828] Stack:
[854807.911839] ffffffff81211cd5 ffffffff81211da6 ffff88040be63e80 ffffffff81211fb6
[854807.911878] ffff880405bcf400 ffff880405bcf400 ffff88040be63eb0 ffffffff81211ff3
[854807.911917] 0000000000088000 00007ffc05f286b0 000000000000000a 00000000000007ff
[854807.911956] Call Trace:
[854807.911972] [<ffffffff81211cd5>] ? generic_fillattr+0x5/0xa0
[854807.911999] [<ffffffff81211da6>] ? vfs_getattr_nosec+0x36/0x40
[854807.912027] [<ffffffff81211fb6>] vfs_getattr+0x26/0x30
[854807.912052] [<ffffffff81211ff3>] vfs_fstat+0x33/0x60
[854807.912076] [<ffffffff812126f4>] SYSC_newfstat+0x24/0x60
[854807.912102] [<ffffffff8120c2cf>] ? do_sys_open+0x1bf/0x2a0
[854807.912129] [<ffffffff8121279e>] SyS_newfstat+0xe/0x10
[854807.912154] [<ffffffff8182db32>] entry_SYSCALL_64_fastpath+0x16/0x71
[854807.912183] Code: 8b 44 24 48 48 8b 7c 24 70 48 8b 74 24 68 48 8b 54 24 60 48 8b 4c 24 58 48 8b 44 24 50 48 8b 6c 24 20 48 81 c4 d0 00 00 00 e9 fd <ff> ff ff 80 00 00 00 00 9c 55 ff 74 24 18 55 48 89 e5 ff 74 24
[854807.912392] RIP [<ffffffff818302a8>] ftrace_stub+0x0/0x8
[854807.912420] RSP <ffff88040be63e50>