Messages in this thread | | | From | Andy Lutomirski <> | Date | Tue, 8 Dec 2020 20:10:17 -0800 | Subject | Re: [PATCH v3 1/4] x86/membarrier: Get rid of a dubious optimization |
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On Thu, Dec 3, 2020 at 9:07 PM Andy Lutomirski <luto@kernel.org> wrote: > > sync_core_before_usermode() had an incorrect optimization. If we're > in an IRQ, we can get to usermode without IRET -- we just have to > schedule to a different task in the same mm and do SYSRET. > Fortunately, there were no callers of sync_core_before_usermode() > that could have had in_irq() or in_nmi() equal to true, because it's > only ever called from the scheduler. > > While we're at it, clarify a related comment. >
Fixes: ac1ab12a3e6e ("lockin/x86: Implement sync_core_before_usermode()")
> Cc: stable@vger.kernel.org > Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> > Signed-off-by: Andy Lutomirski <luto@kernel.org>
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