Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [patch V4 part 4 02/24] x86/int3: Avoid atomic instrumentation | Date | Thu, 14 May 2020 14:51:32 +0200 |
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Peter Zijlstra <peterz@infradead.org> writes: > On Wed, May 13, 2020 at 09:57:52PM -0700, Andy Lutomirski wrote: >> On Tue, May 5, 2020 at 7:15 AM Thomas Gleixner <tglx@linutronix.de> wrote: >> > >> > From: Peter Zijlstra <peterz@infradead.org> >> > >> > Use arch_atomic_*() and READ_ONCE_NOCHECK() to ensure nothing untoward >> > creeps in and ruins things. >> > >> > That is; this is the INT3 text poke handler, strictly limit the code >> > that runs in it, lest it inadvertenly hits yet another INT3. >> >> >> Acked-by: Andy Lutomirski <luto@kernel.org> >> >> Does objtool catch this error? > > It does not. I'll put it on the (endless) todo list..
Well, at least it detects when that code calls out into something which is not in the non-instrumentable section.
As long as instrumentation respects the rules that this section is taboo, this should not happen. Emphasis on *should*.
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