On Mon, Apr 29, 2019 at 12:13 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
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> On Mon, Apr 29, 2019, 12:02 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
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>> If nmi were to break it, it would be a cpu bug.
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> Side note: we *already* depend on sti shadow working in other parts of the kernel, namely sti->iret.
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Where? STI; IRET would be nuts.
Before:
commit 4214a16b02971c60960afd675d03544e109e0d75
Author: Andy Lutomirski <luto@xxxxxxxxxx>
Date: Thu Apr 2 17:12:12 2015 -0700
x86/asm/entry/64/compat: Use SYSRETL to return from compat mode SYSENTER
we did sti; sysxit, but, when we discussed this, I don't recall anyone
speaking up in favor of the safely of the old code.
Not to mention that the crash we'll get if we get an NMI and a
rescheduling interrupt in this path will be very, very hard to debug.
