Vegard Nossum <[email protected]> writes:
> On 5/10/20 10:09 AM, Vegard Nossum wrote:
>
> I spoke a few minutes too soon. Just hit this, if anybody wants to have
> a look:
>
> [ 6402.786418] ------------[ cut here ]------------
> [ 6402.787769] WARNING: CPU: 0 PID: 13802 at arch/x86/kernel/traps.c:811
> do_debug+0x16c/0x210
> [ 6402.820353] Call Trace:
> [ 6402.821043] <#DB>
> [ 6402.821622] debug+0x37/0x70
> [ 6402.822449] RIP: 0010:arch_stack_walk_user+0x79/0x110
That's a cute way to trigger that WARN_ON in the #DB handler.
> [ 6402.816468] DR0: 0000000000000001 DR1: 0000000040006070 DR2:
> 00007ffff7ffd000
> [ 6402.818406] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
> 0000000003b3062a
#DB recursion
[ 6402.832288] RDX: 0000000040006073
27: 48 8b 1a mov (%rdx),%rbx
Breakpoint on user space stack, #DB triggers and the low level ASM
irqflags tracepoint has stacktrace enabled which unwinds into the user
stack and triggers #DB again.
Bah. I know why I want to ban all that tracing muck from low level entry code.
> It might not be related to the patch set, mind.
It's unrelated.
Thanks,
tglx
