Re: system locks up with CONFIG_SLS=Y; 5.17.0-rc

From: Dave Hansen
Date: Wed Mar 16 2022 - 15:03:17 EST


On 3/16/22 11:45, Jamie Heilman wrote:

> int3: 0000 [#1] PREEMPT SMP PTI
> CPU: 0 PID: 2435 Comm: qemu-system-x86 Not tainted 5.17.0-rc8-sls #1
> Hardware name: Dell Inc. Precision WorkStation T3400 /0TP412, BIOS A14 04/30/2012
> RIP: 0010:setc+0x5/0x8 [kvm]
> Code: 00 00 0f 1f 00 0f b6 05 43 24 06 00 c3 cc 0f 1f 80 00 00 00 00 0f 90 c0 c3 cc 0f 1f 00 0f 91 c0 c3 cc 0f 1f 00 0f 92 c0 c3 cc <0f> 1f 00 0f 93 c0 c3 cc 0f 1f 00 0f 94 c0 c3 cc 0f 1f 00 0f 95 c0
> RSP: 0018:ffffc90000a1fc68 EFLAGS: 00000283
> RAX: 0000000000000281 RBX: 0000000000000006 RCX: 0000000000000005
> RDX: ffffffffa01a4024 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffff88810ef76900 R08: 0000000000000000 R09: 0000000000000000
> R10: ffff88810ee54000 R11: 0000000000000000 R12: ffffffffa01d5720
> R13: 0000000000000000 R14: 0000000000000000 R15: ffff88810ef76900
> FS: 00007f23ecd79640(0000) GS:ffff888233c00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000000 CR3: 0000000108df8000 CR4: 00000000000426f0
> Call Trace:
> <TASK>
> ? x86_emulate_insn+0x76b/0xe00 [kvm]

Ooh, fun!

This hit one of the new int3's in "ASM_RET" in "setc" in
arch/x86/kvm/emulate.c:

FOP_SETCC(setc)

Did the extra 'int3' screw up some presumed jump offset or something?