Messages in this thread | | | Date | Sun, 10 May 2020 10:17:22 -0400 | From | Sasha Levin <> | Subject | Re: [PATCH v10 00/18] Enable FSGSBASE instructions |
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On Sun, May 10, 2020 at 12:15:34PM +0200, Thomas Gleixner wrote: >Vegard Nossum <vegard.nossum@oracle.com> 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 for testing Vegard!
-- Thanks, Sasha
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