On 03/14/2018 10:29 PM, Oleg Nesterov wrote: > On 03/13, Ravi Bangoria wrote: >> +static bool sdt_valid_vma(struct trace_uprobe *tu, struct vm_area_struct *vma) >> +{ >> + unsigned long vaddr = vma_offset_to_vaddr(vma, tu->ref_ctr_offset); >> + >> + return tu->ref_ctr_offset && >> + vma->vm_file && >> + file_inode(vma->vm_file) == tu->inode && >> + vma->vm_flags & VM_WRITE && >> + vma->vm_start <= vaddr && >> + vma->vm_end > vaddr; >> +} > Perhaps in this case a simple > > ref_ctr_offset < vma->vm_end - vma->vm_start > > check without vma_offset_to_vaddr() makes more sense, but I won't insist. > Hmm... I'm not quite sure. Will rethink and get back to you. > >> +static void sdt_increment_ref_ctr(struct trace_uprobe *tu) >> +{ >> + struct uprobe_map_info *info; >> + struct vm_area_struct *vma; >> + unsigned long vaddr; >> + >> + uprobe_start_dup_mmap(); >> + info = uprobe_build_map_info(tu->inode->i_mapping, >> + tu->ref_ctr_offset, false); > Hmm. This doesn't look right. > > If you need to find all mappings (and avoid the races with fork/dup_mmap) you > need to take this semaphore for writing, uprobe_start_dup_mmap() can't help. Oops. Yes. Will change it. Thanks for the review :) Ravi -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html