| From | Andy Lutomirski <> | Date | Tue, 29 Sep 2015 10:25:52 -0700 | Subject | Re: [PATCH 3.14 79/84] x86/nmi/64: Switch stacks on userspace NMI entry |
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On Tue, Sep 29, 2015 at 8:19 AM, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > 3.14-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Andy Lutomirski <luto@kernel.org> > > commit 9b6e6a8334d56354853f9c255d1395c2ba570e0a upstream. > > Returning to userspace is tricky: IRET can fail, and ESPFIX can > rearrange the stack prior to IRET.
Just a heads up: under very strange circumstances (most likely requires booting with paravirt-noreplace, which is hopefully only used by Sasha), this causes a regression that's fixed by 83c133cf11fb0e68a51681447e372489f052d40e. I'm not 100% sure that the regression is observable at all, because the same strange configuration may also hit the bug fixed by fc57a7c68020dcf954428869eafd934c0ab1536f before the regression can trigger.
Anyway, you've been warned. I wouldn't worry too much about it, though.
--Andy
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