From: James Morse Date: Sat, 10 Sep 2016 10:34:14 +0000 (+1000) Subject: fs/proc/task_mmu.c: make the task_mmu walk_page_range() limit in clear_refs_write... X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=13f5e25729d972e4aeacb7a626605d419fc2fed5;p=deliverable%2Flinux.git 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@arm.com Signed-off-by: James Morse Acked-by: Naoya Horiguchi Signed-off-by: Andrew Morton --- diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 187d84ef9de9..1026b7862896 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1068,7 +1068,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, } 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);