Messages in this thread | | | Date | Fri, 21 Aug 2015 08:23:28 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86/traps: Weaken context tracking entry assertions |
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* Andy Lutomirski <luto@kernel.org> wrote:
> We were asserting that we were all the way in CONTEXT_KERNEL when exception > handlers were called. While having this be true is, I think, a nice goal (or > maybe a variant in which we assert that we're in CONTEXT_KERNEL or some new IRQ > context), we're not quite there. > > In particular, if an IRQ interrupts the SYSCALL prologue and the IRQ handler in > turn causes an exception, the exception entry will be called in RCU IRQ mode but > with CONTEXT_USER.
Hm, so what harm would there be in making IRQ handlers enter CONTEXT_KERNEL? Would nohz-full break?
I'd rather have a bit more tracking overhead here than lose such useful sanity checks.
Thanks,
Ingo
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