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uprobes: Kill dup_mmap()->uprobe_mmap(), simplify uprobe_mmap/munmap
1. Kill dup_mmap()->uprobe_mmap(), it was only needed to calculate new_mm->uprobes_state.count removed by the previous patch. If the forking process has a pending uprobe (int3) in vma, it will be copied by copy_page_range(), note that it checks vma->anon_vma so "Don't copy ptes" is not possible after install_breakpoint() which does anon_vma_prepare(). 2. Remove is_swbp_at_addr() and "int count" in uprobe_mmap(). Again, this was needed for uprobes_state.count. As a side effect this fixes the bug pointed out by Srikar, this code lacked the necessary put_uprobe(). 3. uprobe_munmap() becomes a nop after the previous patch. Remove the meaningless code but do not remove the helper, we will need it. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
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647c42dfd4
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2 changed files with 3 additions and 30 deletions
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@ -1010,7 +1010,7 @@ int uprobe_mmap(struct vm_area_struct *vma)
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struct list_head tmp_list;
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struct uprobe *uprobe, *u;
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struct inode *inode;
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int ret, count;
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int ret;
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if (!atomic_read(&uprobe_events) || !valid_vma(vma, true))
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return 0;
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@ -1023,8 +1023,6 @@ int uprobe_mmap(struct vm_area_struct *vma)
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build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list);
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ret = 0;
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count = 0;
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list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
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if (!ret) {
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unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset);
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@ -1034,19 +1032,11 @@ int uprobe_mmap(struct vm_area_struct *vma)
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* We can race against uprobe_register(), see the
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* comment near uprobe_hash().
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*/
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if (ret == -EEXIST) {
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if (ret == -EEXIST)
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ret = 0;
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if (!is_swbp_at_addr(vma->vm_mm, vaddr))
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continue;
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}
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if (!ret)
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count++;
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}
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put_uprobe(uprobe);
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}
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mutex_unlock(uprobes_mmap_hash(inode));
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return ret;
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@ -1057,27 +1047,13 @@ int uprobe_mmap(struct vm_area_struct *vma)
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*/
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void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
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{
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struct list_head tmp_list;
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struct uprobe *uprobe, *u;
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struct inode *inode;
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if (!atomic_read(&uprobe_events) || !valid_vma(vma, false))
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return;
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if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */
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return;
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inode = vma->vm_file->f_mapping->host;
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if (!inode)
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return;
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mutex_lock(uprobes_mmap_hash(inode));
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build_probe_list(inode, vma, start, end, &tmp_list);
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list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
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put_uprobe(uprobe);
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}
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mutex_unlock(uprobes_mmap_hash(inode));
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/* TODO: unmapping uprobe(s) will need more work */
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}
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/* Slot allocation for XOL */
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@ -454,9 +454,6 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
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if (retval)
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goto out;
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if (file)
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uprobe_mmap(tmp);
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}
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/* a new mm has just been created */
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arch_dup_mmap(oldmm, mm);
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