| Date | Wed, 22 Nov 2017 06:35:27 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH v2 01/18] x86/entry/64: Fix entry_SYSCALL_64_after_hwframe IRQ tracing |
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* Andy Lutomirski <luto@kernel.org> wrote:
> When I added entry_SYSCALL_64_after_hwframe, I left TRACE_IRQS_OFF > before it. This means that users of entry_SYSCALL_64_after_hwframe > were responsible for invoking TRACE_IRQS_OFF, and the one and only > user (added in the same commit) got it wrong. > > I think this would manifest as a warning if a Xen PV guest with > CONFIG_DEBUG_LOCKDEP=y were used with context tracking. (The > context tracking bit is to cause lockdep to get invoked before we > turn IRQs back on.) I haven't tested that for real yet because I > can't get a kernel configured like that to boot at all on Xen PV. > I've reported it upstream. The problem seems to be that Xen PV is > missing early #UD handling, is hitting some WARN, and we rely on
JFYI, seems the changelog got truncated at this point - I simply removed that partial sentence as I suppose those details will be explained in the Xen fix anyway.
> Move TRACE_IRQS_OFF below the label.
Thanks,
Ingo
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