>>> On 21.02.18 at 17:53, <[email protected]> wrote: > * Jan Beulich <[email protected]> wrote: > >> Using just the leaf page table entry flags would cause a false warning >> in case _PAGE_RW is clear or _PAGE_NX is set in a higher level entry. >> Hand through both the current entry's flags as well as the accumulated >> effective value (the latter as pgprotval_t instead of pgprot_t, as it's >> not an actual entry's value). >> >> This in particular eliminates the false W+X warning when running under >> Xen, as commit 2cc42bac1c ("x86-64/Xen: eliminate W+X mappings") has to >> make the necessary adjustment in L2 rather than L1 (the reason is >> explained there). I.e. _PAGE_RW is clear there in L1, but _PAGE_NX is >> set in L2. >> >> Signed-off-by: Jan Beulich <[email protected]> >> Reviewed-by: Juergen Gross <[email protected]> >> --- >> v2: Re-base onto tip tree. Add Xen related paragraph to description. >> --- >> arch/x86/mm/dump_pagetables.c | 92 > ++++++++++++++++++++++++++---------------- >> 1 file changed, 57 insertions(+), 35 deletions(-) > > There's a build failure with CONFIG_KASAN=y enabled: > > arch/x86/mm/dump_pagetables.c: In function ‘kasan_page_table’: > arch/x86/mm/dump_pagetables.c:365:3: error: too few arguments to function > ‘note_page’ > arch/x86/mm/dump_pagetables.c:238:13: note: declared here
Oh, I see. Question though is what to pass as the extra argument: Do I need to pass in the caller's effective rights, or should I take kasan_page_table()'s checking against kasan_zero_p?d as an indication that the effective permission is zero here? I'm sorry for this probably trivial question, but I know nothing about how KASAN works. Jan
