Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 29 Apr 2019 12:24:23 -0700 | Subject | Re: [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation |
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On Mon, Apr 29, 2019 at 12:13 PM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > > > On Mon, Apr 29, 2019, 12:02 Linus Torvalds <torvalds@linux-foundation.org> wrote: >> >> >> >> If nmi were to break it, it would be a cpu bug. > > > Side note: we *already* depend on sti shadow working in other parts of the kernel, namely sti->iret. >
Where? STI; IRET would be nuts.
Before:
commit 4214a16b02971c60960afd675d03544e109e0d75 Author: Andy Lutomirski <luto@kernel.org> 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.
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