Messages in this thread |  | | Date | Thu, 31 Oct 2013 19:22:18 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 12/13] tracing/uprobes: Add more fetch functions |
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On 10/29, Namhyung Kim wrote: > > +static void __user *get_user_vaddr(unsigned long addr, struct trace_uprobe *tu) > +{ > + unsigned long pgoff = addr >> PAGE_SHIFT; > + struct vm_area_struct *vma; > + struct address_space *mapping; > + unsigned long vaddr = 0; > + > + if (tu == NULL) { > + /* A NULL tu means that we already got the vaddr */ > + return (void __force __user *) addr; > + } > + > + mapping = tu->inode->i_mapping; > + > + mutex_lock(&mapping->i_mmap_mutex); > + vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { > + if (vma->vm_mm != current->mm) > + continue; > + if (!(vma->vm_flags & VM_READ)) > + continue; > + > + vaddr = offset_to_vaddr(vma, addr); > + break; > + } > + mutex_unlock(&mapping->i_mmap_mutex); > + > + WARN_ON_ONCE(vaddr == 0);
Hmm. But unless I missed something this "addr" passed as an argument can be wrong? And if nothing else this or another thread can unmap the vma?
Oleg.
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