On Wed, Aug 23, 2017 at 10:58:42AM -0600, Tycho Andersen wrote: > Hi Mark, > > On Mon, Aug 14, 2017 at 05:50:47PM +0100, Mark Rutland wrote: > > That said, is there any reason not to use flush_tlb_kernel_range() > > directly? > > So it turns out that there is a difference between __flush_tlb_one() and > flush_tlb_kernel_range() on x86: flush_tlb_kernel_range() flushes all the TLBs > via on_each_cpu(), where as __flush_tlb_one() only flushes the local TLB (which > I think is enough here). That sounds suspicious; I don't think that __flush_tlb_one() is sufficient. If you only do local TLB maintenance, then the page is left accessible to other CPUs via the (stale) kernel mappings. i.e. the page isn't exclusively mapped by userspace. Thanks, Mark. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
