When we try to visit the pagemap of a tagged userspace pointer, we find that the start_vaddr is not correct because of the tag. To fix it, we should untag the usespace pointers in pagemap_read(). Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx> --- fs/proc/task_mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 5066b0251ed8..ee0ac09e79fc 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1541,11 +1541,11 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, src = *ppos; svpfn = src / PM_ENTRY_BYTES; - start_vaddr = svpfn << PAGE_SHIFT; + start_vaddr = untagged_addr(svpfn << PAGE_SHIFT); end_vaddr = mm->task_size; /* watch out for wraparound */ - if (svpfn > mm->task_size >> PAGE_SHIFT) + if (start_vaddr > mm->task_size) start_vaddr = end_vaddr; /* -- 2.18.0
