Messages in this thread | | | Date | Wed, 28 Aug 2019 17:51:10 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [patch 1/2] x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable() |
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On Wed, 28 Aug 2019, Dave Hansen wrote: > On 8/28/19 7:24 AM, Thomas Gleixner wrote: > > From: Song Liu <songliubraving@fb.com> > > > > pti_clone_pmds() assumes that the supplied address is either: > > > > - properly PUD/PMD aligned > > or > > - the address is actually mapped which means that independent > > of the mapping level (PUD/PMD/PTE) the next higher mapping > > exist. > > > > If that's not the case the unaligned address can be incremented by PUD or > > PMD size wrongly. All callers supply mapped and/or aligned addresses, but > > for robustness sake, it's better to handle that case proper and to emit a > > warning. > > Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> > > Song, did you ever root-cause the performance regression? I thought > there were still some mysteries there.
See Peter's series to rework the ftrace code patching ...
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