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405e1133d0
set_memory_nx() (and set_memory_x()) currently differ in behavior from all other set_memory_*() functions when encountering a virtual address space hole within the kernel address range: They stop processing at the hole, but nevertheless report success (making the caller believe the operation was carried out on the entire range). While observed to be a problem - triggering the CONFIG_DEBUG_WX warning - only with out of tree code, I suspect (but didn't check) that on x86-64 the CONFIG_DEBUG_PAGEALLOC logic in free_init_pages() would, when called from free_initmem(), have the same effect on the set_memory_nx() called from mark_rodata_ro(). This unexpected behavior is a result of change_page_attr_set_clr() special casing changes to only the NX bit, in that it passes "false" as the "checkalias" argument to __change_page_attr_set_clr(). Since this flag becomes the "primary" argument of both __change_page_attr() and __cpa_process_fault(), the latter would so far return success without adjusting cpa->numpages. Success to the higher level callers, however, means that whatever cpa->numpages currently holds is the count of successfully processed pages. The cases when __change_page_attr() calls __cpa_process_fault(), otoh, don't generally mean the entire range got processed (as can be seen from one of the two success return paths in __cpa_process_fault() already adjusting ->numpages). Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/56BB0AD402000078000D05BF@prv-mh.provo.novell.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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|---|---|---|
| .. | ||
| kmemcheck | ||
| amdtopology.c | ||
| debug_pagetables.c | ||
| dump_pagetables.c | ||
| extable.c | ||
| fault.c | ||
| gup.c | ||
| highmem_32.c | ||
| hugetlbpage.c | ||
| init_32.c | ||
| init_64.c | ||
| init.c | ||
| iomap_32.c | ||
| ioremap.c | ||
| kasan_init_64.c | ||
| kmmio.c | ||
| Makefile | ||
| mm_internal.h | ||
| mmap.c | ||
| mmio-mod.c | ||
| mpx.c | ||
| numa_32.c | ||
| numa_64.c | ||
| numa_emulation.c | ||
| numa_internal.h | ||
| numa.c | ||
| pageattr-test.c | ||
| pageattr.c | ||
| pat_internal.h | ||
| pat_rbtree.c | ||
| pat.c | ||
| pf_in.c | ||
| pf_in.h | ||
| pgtable_32.c | ||
| pgtable.c | ||
| physaddr.c | ||
| physaddr.h | ||
| setup_nx.c | ||
| srat.c | ||
| testmmiotrace.c | ||
| tlb.c | ||