Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 21 May 2014 14:59:38 -0700 | Subject | Re: [RFC] x86_64: A real proposal for iret-less return to kernel |
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On Wed, May 21, 2014 at 2:55 PM, Borislav Petkov <bp@alien8.de> wrote: > On Wed, May 21, 2014 at 02:52:55PM -0700, Andy Lutomirski wrote: >> Why is it a problem if user_mode_vm(regs)? Conversely, why is sending >> a signal a remotely reasonable thing to do if !user_mode_vm(regs)? > > Let me quote Jiri: > > (1) task sends signal to itself > (2) it acquires sighand->siglock so that it's able to queue the signal > (3) MCE triggers
...and !user_mode_vm(regs), and hence we're IN_KERNEL, and we should presumably just panic instead of trying to send a signal.
I missed the IN_KERNEL thing because I didn't realize that ->cs was copied to struct mce.
--Andy
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