From: James Morse <james.morse@xxxxxxx> Subject: fs/proc/task_mmu.c: make the task_mmu walk_page_range() limit in clear_refs_write() obvious Trying to walk all of virtual memory requires architecture specific knowledge. On x86_64, addresses must be sign extended from bit 48, whereas on arm64 the top VA_BITS of address space have their own set of page tables. clear_refs_write() calls walk_page_range() on the range 0 to ~0UL, it provides a test_walk() callback that only expects to be walking over VMAs. Currently walk_pmd_range() will skip memory regions that don't have a VMA, reporting them as a hole. As this call only expects to walk user address space, make it walk 0 to 'highest_vm_end'. Link: http://lkml.kernel.org/r/1472655792-22439-1-git-send-email-james.morse@xxxxxxx Signed-off-by: James Morse <james.morse@xxxxxxx> Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/task_mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN fs/proc/task_mmu.c~mm-proc-make-the-task_mmu-walk_page_range-limit-in-clear_refs_write-obvious fs/proc/task_mmu.c --- a/fs/proc/task_mmu.c~mm-proc-make-the-task_mmu-walk_page_range-limit-in-clear_refs_write-obvious +++ a/fs/proc/task_mmu.c @@ -1070,7 +1070,7 @@ static ssize_t clear_refs_write(struct f } mmu_notifier_invalidate_range_start(mm, 0, -1); } - walk_page_range(0, ~0UL, &clear_refs_walk); + walk_page_range(0, mm->highest_vm_end, &clear_refs_walk); if (type == CLEAR_REFS_SOFT_DIRTY) mmu_notifier_invalidate_range_end(mm, 0, -1); flush_tlb_mm(mm); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
